PMID: 42569619

Gene: MYBPC3

HGNC ID: 7551

Case1: 42 year old Male

DiseaseAssertion: History of acromegaly

FamilyInfo: N/A

ParentalTesting: No parental testing done

CasePresentingHPOs: “elevated levels of growth hormone, and IGF-1”

CaseHPOFreeText: Genetic analysis revealed a heterozygous nonsense variant in MYBPC3

CaseNotHPOs: N/A

CaseNotHPOFreeText: Cardiac MRI revealed normal dimensions of thoracic aorta, no evidence of stenosis or aneurysms

CasePreviousTesting: An oral glucose tolerance test was performed, growth hormone failed to suppress below 0.88

Genotyping Method: Echocardiography used to confirm enlarged left atrium, increased septal thickness, mild mitral and tricuspid regurgitation

Variant: NM_000256.3 c.3408C>G MANE select

ClinVar: 851340

CAID: CA380313523

gnomAD: chr11-47332896

https://www.ncbi.nlm.nih.gov/clinvar/variation/851340/?term=%22c.3408C%3EG%22%5BVARNAME%5D+AND+%22MYBPC3%22%5BGENE%5D

PMID:30565988

Gene:TNNT2

HGNC ID:11949

Case#:A 65-year-old woman with severe hypertrophic cardiomyopathy

DiseaseAssertion:Severe hypertrophic cardiomyopathy

FamilyInfo:no information reported

ParentalTesting:no parental testing reported

CasePresentingHPOs:HP:0001639

CaseHPOFreeText: gene panel testing that identified a single variant

CaseNotHPOs: not found

CaseNotHPOFreeText: not found

CasePreviousTesting: gene panel testing that identified a single variant

Genotyping Method:clinical gene panel testing

FunctionalAnalysis: rapid insertion of TNNT2 gene variants into induced pluripotent stem cell-differentiated cardiomyocytes (iPSC-CMs) for functional annotation of the variants for (E251D)(Figure B)

Variant:c.753G>T (p.Glu251Asp)

ClinVar:not found

CAID:CA090003

gnomAD:not found

AdditionalInfo:not reported

Case#: 1. Patient II-4 43 years

DiseaseAssertion: Hypertrophic cardiomyopathy and left ventricular noncompaction

FamilyInfo: Several family members have heart disease. One relative died from cardiac arrest at age 50.

ParentalTesting: NR

CasePresentingHPOs: NR

CaseHPOFreeText: The patient had thickened heart muscle, abnormal heartbeats, and extra ridges and deep spaces in the heart muscle.

CaseNotHPOs: NR

CaseNotHPOFreeText: NR

CasePreviousTesting: ECG, heart monitoring, heart ultrasound, and genetic testing

Genotyping Method: Next- generation sequencing and sanger sequencing

FunctionalAnalysis: computer testing suggested the ACTC1 gene change could weaken the protein

Variant: NM_005159.4:c.62C>T

Clinvar: 410264

CAID: CA16614451

gnomAD: NR

AdditionalInfo: His heart pumping ability was 55%. This article reported changes in his heart muscle cells.

Case#: 2 Patient II-5 46 years old

DiseaseAssertion: HCM and LVNC

FamilyInfo: Several family members have heart disease. One relative died from cardiac arrest at age 50.

ParentalTesting: NR

CasePresentingHPOs: NR

CaseHPOFreeText: The patient had thickened and enlarged heart muscle, abnormal heartbeats, and deep spaces in his heart muscle. He als had temporary episodes of reduced blood flow to the brain.

CaseNotHPOs: NR

CaseNotHPOFreeText: NR

CasePreviousTesting: ECG, heart monitoring, heart ultrasound, heart MRI, heart biopsy and genetic testing

Genotyping Method: NGS and sanger sequencing

FunctionalAnalysis:computer testing suggested the ACTC1 gene change could weaken the protein.

Variant: NM_005159.4:c.62C>T

Clinvar: 410264

CAID: CA16614451

gnomAD: NR

AdditionalInfo: His heart pumping ability was 30%. He received a defibrillator and was considered for a heat transplant. He also had a second gene change in TTN.

Case#: 3 Patient II-1 10 years

DiseaseAssertion: left ventricular noncompaction

FamilyInfo: Several family members have heart disease. One relative died from cardiac arrest at age 50.

ParentalTesting: NR

CasePresentingHPOs: NR

CaseHPOFreeText: The patient had extra ridges and deep spaces in his heart muscle. His ECG also showed changes in his heart's electrical activity.

CaseNotHPOs: NR

CaseNotHPOFreeText: Normal heart muscle thickness and normal heart pumping ability.

CasePreviousTesting: ECG, heart monitoring, heart ultrasound, heart biopsy and genetic testing

Genotyping Method: NGS and sanger sequencing

FunctionalAnalysis:computer testing suggested the ACTC1 gene change could weaken the protein.

Variant: NM_005159.4:c.62C>T

Clinvar: 410264

CAID: CA16614451

gnomAD: NR

AdditionalInfo: His heart pumping ability was 63%.He received medication and remained stable during follow up.

Case#: 4 Patient III-2 14 years

DiseaseAssertion: HCM and LVNC

FamilyInfo: Several family members have heart disease. One relative died from cardiac arrest at age 50.

ParentalTesting: NR

CasePresentingHPOs: NR

CaseHPOFreeText: The patient had thickened heart muscle extra ridges and deep spaces in his heart, and episodes of fast or abnormal hearbeats.

CaseNotHPOs: NR

CaseNotHPOFreeText: Heart MRI did not show sign of heart muscle scarring

CasePreviousTesting: ECG, heart monitoring, heart ultrasound, heart biopsy and genetic testing

Genotyping Method: NGS and sanger sequencing

FunctionalAnalysis:computer testing suggested the ACTC1 gene change could weaken the protein.

Variant: NM_005159.4:c.62C>T

Clinvar: 410264

CAID: CA16614451

gnomAD: NR

AdditionalInfo: His heart pumping ability was 60%.He received medication and remained stable during follow up.

Case:Male, born at 39 weeks of gestation, evaluated during infancy-age 6.

DiseaseAssertion:Arthrogryposis multiplex congenita (AMC). The patient also had Shone's complex with coarctation of the aorta. Cardiomyopathy not reported.

Familyinfo:The patient was the first child of unrelated parents. No family history of arthrogryposis multiplex congenita was reported.

ParentalTesting:The ACTC1 c.650A>C (p.Lys217Thr) variant was identified as de novo. Neither parent was reported to carry the variant.

CasePresentingHPOs:Limited range of motion in wrists, Limited range of motion in fingers, Limited range of motion in thumbs, Hip contractures, Knee contractures, Bilateral clubfeet, Clenched hands, Hypotonia, Lower extremity weakness,

CaseHPOFreeText:The patient was born at 39 weeks of gestation. At birth, he had limited range of motion in the wrists, fingers, thumbs, hips, and knees, along with bilateral clubfeet. Echocardiography revealed Shone's complex, including coarctation of the aorta, which required surgical repair. At age 1, he had clenched hands with deep single palmar creases, overlapping toes, and hypoplastic fifth toenails. He also had truncal hypotonia, mild lower extremity weakness, and delayed gross motor milestones. At age 3, moderate wrist contractures, thumb-in-palm deformities, and mild bilateral hip contractures were observed. He began walking independently at age 4. At age 5, he underwent additional heart surgery and pacemaker insertion.

CaseNotHPOs:Scoliosis: not identified on spine X-rays, cognitive difficulties: not reported

CaseNOTHPOFreeText:The patient did not have reported cognitive difficulties. Spine X-rays did not reveal scoliosis.

CasePreviousTesting:Genome sequencing was performed to identify genetic variants associated with the patient's clinical presentation. Echocardiography was used to identify Shone's complex and coarctation of the aorta.

GenotypingMethod:Genome sequencing. Plasmid sequences used for the functional experiments were verified by Sanger sequencing.

FunctionalAnalysis:In vitro functional studies were performed using MC3T3-E1 preosteoblastic cells. The p.Lys217Thr variant did not demonstrate a clear effect on ACTC1 protein expression or localization compared with wild-type ACTC1. The authors reported no apparent reduction in protein levels or impaired actin filament organization.

Variant:NM_005159.5 (ACTC1): c.650A>C; p.Lys217Thr.

ClinVar:not reported

CAID:not reported

gnomAD:not reported

AdditionalInfo:The variant was identified as de novo and classified as likely pathogenic using ACMG criteria (PS2, PM1, PM2, PP2, PP3). Although functional testing did not demonstrate a clear effect on ACTC1 protein expression or localization, the authors considered the variant likely pathogenic based on the genetic and clinical evidence.

PMID: 42458772 Gene: ACTC1 HGNCID: 143

Case:Female, born at 34 weeks of gestation, 5 years old at the first detailed examination, 8 years old during a later clinical description.

DiseaseAssertion:Arthrogryposis multiplex congenita (AMC). Cardiomyopathy not reported.

Familyinfo:The patient was the first child of unrelated parents. Her mother and one maternal aunt were born with bilateral clubfeet and later developed scoliosis. The mother also had a history of cleft palate. Neither the mother nor the patient had a reported history of cardiac problems.

ParentalTesting:The patient's mother carried the same heterozygous ACTC1 c.325G>A (p.Glu109Lys) variant. The variant was therefore inherited from the mother. CasePresentingHPOs:Bilateral clubfeet, scoliosis, cleft palate, neck webbing, camptodactyly, joint contractures.

CaseHPOFreeText:The patient was born by cesarean section at 34 weeks of gestation. Bilateral clubfeet, cleft palate, neck webbing, and spinal deformity were noted. At age 5, she had severe scoliosis measuring 120 degrees and severe short stature. At age 8, mild camptodactyly of both hands and mild contractures of the neck, left hip, both knees, and feet were observed. She had no significant mobility or cognitive difficulties and was independent in self-care activities.

CaseNotHPOs:No reported cardiac problems, no significant cognitive difficulties, no significant mobility difficulties.

CaseNOTHPOFreeText:The patient had no reported cardiac phenotype despite carrying an ACTC1 variant. Her mother also had no history of cardiac problems.

CasePreviousTesting:Genome sequencing was performed to identify genetic variants associated with the patient's clinical presentation.

GenotypingMethod:Genome sequencing. Plasmid sequencing was also verified by Sanger sequencing for the experimental functional studies.

FunctionalAnalysis:In vitro functional studies were performed using MC3T3-E1 preosteoblastic cells. The p.Glu109Lys variant caused decreased ACTC1 protein levels and impaired actin filament assembly. Immunofluorescence and Western blotting were used to evaluate protein expression and actin filament organization.

Variant:NM_005159.5 (ACTC1): c.325G>A; p.Glu109Lys.

ClinVar:not reported

CAID:not reported

gnomAD:not found

AdditionalInfo:The variant was inherited from the patient's mother, who also had bilateral clubfeet, scoliosis, and a history of cleft palate. The authors classified the variant as likely pathogenic using ACMG criteria (PM1, PM2, PP1, PP2, PP3). The functional studies demonstrated reduced ACTC1 protein levels and impaired actin filament assembly.

PMID:41969674

Gene:TNNT2

HGNC ID:11949

Case#:male, 41, DCM

DiseaseAssertion:dilated cardiomyopathy

FamilyInfo:The proband reported that his mother died suddenly at approximately 35 years of age (specific cause unknown). Other family members were healthy with no history of cardiac disease. Written informed consent was obtained from all participants.

ParentalTesting:no parental testing reported. Sanger sequencing of available family members (daughter, half-brother, maternal uncle and maternal aunt) confirmed that none carried the variant, supporting its de novo origin

CasePresentingHPOs:HP:0002875, HP:0001644, HP:4000141, HP:6000313

CaseHPOFreeText: ECG showed sinus bradycardia, occasional atrial premature beats, delayed atrioventricular conduction, left atrial enlargement, left ventricular high voltage, incomplete right bundle branch block, and ST-T changes (Figure 1C). CMR revealed late gadolinium enhancement (LGE) in the basal to mid-septal and anterolateral segments of the left ventricle (Figure 1D).

CaseNotHPOs:HP:0000822, HP:0003077

CaseNotHPOFreeText:He denied a history of hyperlipidemia, hypertension, or substance abuse.

CasePreviousTesting:No reports of previous testing

Genotyping Method:whole-exome sequencing and Sanger sequencing

FunctionalAnalysis:not reported

Variant:c.547C>T p.Arg183Trp

ClinVar:43628

CAID:CA004294

gnomAD:Overall allele frequency: 0.000001239

AdditionalInfo:not reported

Case2: Full term male

DiseaseAssertion: poor feeding, respiratory distress, and cyanosis

FamilyInfo: Healthy non‐consanguineous parents. Positive for HCM on the mother's side: the maternal grandfather died from HCM at the age of 52 years, and a brother of the maternal grandfather was also affected. The parents and siblings of the patient showed no abnormalities on cardiological examination.

ParentalTesting:

CasePresentingHPOs: HP:0001714, HP:0011623, HP:0010438

CaseHPOFreeText: On cardiac catheterisation, both ventricles were found to be hypertrophic. There was mild shunting at the level of the foramen ovale. The pressures in the right ventricle and pulmonary artery were pathologically high, while the pressures in the left atrium and ventricle were normal (though with high A waves). There was a total left to right shunt of 43% of the pulmonary circulation, partly caused by a low muscular ventricular septal defect.

CaseNotHPOs: NR

CaseNotHPOFreeText: NR

CasePreviousTesting: NR

Genotyping Method: NR

FunctionalAnalysis: NR

Variant: NM_001242672.3(TTC34):c.2827C>T (p.Arg943Trp)

ClinVar: 3329883

CAID: NR

gnomAD: 1-2573220-G-A

AdditionalInfo: NR

Case1: gestational age 40 weeks female

DiseaseAssertion: Poor feeding, cyanosis, and difficulty with breathing.

FamilyInfo: Healthy non‐consanguineous parents. Echocardiographic in the mother and sister were normal. Father had mild dilatation of the left atrium with an abnormal flow pattern in the mitral valve, otherwise healthy.

ParentalTesting: c.2373_2374insG mutation found in the mother

CasePresentingHPOs:HP:0025169,

CaseHPOFreeText: hypertrophic non‐obstructive cardiomyopathy with poor left and right ventricular systolic function. The left ventricular end diastolic diameter measured 17.3 mm (99% of normal), end systolic diameter 12.9 mm (116% of normal), and left ventricular posterior wall 3.6 mm (111% of normal). The intraventricular septum measured 11.8 mm (288% of normal). The shortening fraction of the left ventricle was decreased to 25%. Multiple abnormal small communications with a minimal flow between a coronary artery and the right ventricle were observed in the apical portion of the interventricular septum. There were no structural congenital heart defects.

CaseNotHPOs: NR

CaseNotHPOFreeText: NR

CasePreviousTesting: NR

Genotyping Method:

FunctionalAnalysis: NR

Variant: NM_006073.4(TRDN):c.1624+1G>A

ClinVar:2152664

CAID: CA147231745

gnomAD:NR

AdditionalInfo:NR

PMID: 16679492

Gene: MYBPC3

HGNC ID:7551

Case3: Male, 44,57,17, 2 Native American, European, Guaranda, Zaruma, Ibarra

DiseaseAssertion: asymmetric septal hypertrophy, dynamic left ventricular outflow tract obstruction, HCM, fatigue and presyncope

FamilyInfo: family history included parental hypertension and cancer, Relatives had cardiovascular conditions, including a paternal uncle with myocardial infarction at 58, another with a heart murmur, and a grandmother with hypertension

ParentalTesting: Family history of first degree relatives with myocardial infarction

CasePresentingHPOs: HP: 000256.3, HP: 033118.3, HP:000540.2 “Gene encodes the cardiac isoform of myosin-binding, Gene encodes an enzyme that is expressed in adult skeletal muscle, gene encodes a ryanodine receptor found in skeletal muscle”

CaseHPOFreeText: N/A

CaseNotHPOs: HP: 004168.3, HP: 000384.2, HP: 020433.4

CaseNotHPOFreeText: “Mutations in gene are linked to Leigh syndrome, mutations to gene are linked to diseases affecting plasma cholesterol, gene encodes a protein to mediate cross talk between cell surface and intracellular ion channels”

CasePreviousTesting: TruSight Cardio panel for inherited cardiac disorders

Genotyping Method: Next-generation sequencing (NGS)

FunctionalAnalysis: N/A

Variant: NM_000256.3 c.772G>A MANE select

ClinVar: 42792

CAID: CA015823

gnomAD: 0.00003

https://www.ncbi.nlm.nih.gov/clinvar/variation/42792/?term=%22p.Glu258Lys%22%5BVARNAME%5D+AND+%22MYBPC3%22%5BGENE%5D

PMID: 41647802

Gene: MYBPC3

HGNC ID: 7551

Case2: 12 year old Male, 9 month old Female

Disease Assertion:Double atrial and right ventricular hypertrophy, intermittent chest pain and left ventricular hypertrophy

FamilyInfo: No family history of sudden cardiac death, HCM, or coronary artery disease, granduncle had HCM history and died at 67

ParentalTesting: Heterozygous mutation myosin binding protein C gene(MYBPC3) is confirmed in mother

CasePresentingHPOs: “enlarged left and right atria, double ventricular hypertrophy, interventricular septal thickness”

CaseHPOFreeText: N/A

CaseNotHPOs: N/A

CaseNotHPOFreeText: N/A

CasePreviousTesting: TruSight Cardio panel for inherited cardiac disorders

Genotyping Method: Sanger sequencing

FunctionalAnalysis: N/A

Variant: TNN c.50171G>T, NM_000256.3 c.2459G>A MANE select

ClinVar: 8617

CAID: CA012326

gnomAD: chr11-47337534

https://reg.clinicalgenome.org/redmine/projects/registry/genboree_registry/by_caid?caid=CA012326&

PMID: 41726140

Gene: MYBPC3

HGNC ID: 7551

PMID: 41561115

Gene: MYBPC3

HGNC ID: 7551

Case1: 40-year-old Chinese male

DiseaseAssertion: exertional dyspnea for one year and substernal chest pain for one week.

FamilyInfo: Father experienced sudden cardiac death (SCD) at the age of 41. Targeted region capture and second-generation high throughput sequencing were performed on the proband’s cousin, cousin sister, and sister. Results demonstrated that all family members carried the MYBPC3 c.1827dupC variant. Pedigree in Fig. 3

ParentalTesting: NR

CasePresentingHPOs: HP:0025169, HP:0025168, HP:0031675, HP:0001714,

CaseHPOFreeText: harsh systolic ejection murmur at the left sternal border (3rd–4th intercostal spaces), accentuated by Valsalva maneuver. Echocardiography revealed the following key findings: severe asymmetric septal hypertrophy, characterized by an interventricular septal thickness (IVsd) at end-diastole of 25–30 mm and a left ventricular posterior wall dimensions (LVPWd) of 21 mm, with a preserved left ventricular ejection fraction (LVEF) of 59%

CaseNotHPOs: NR

CaseNotHPOFreeText: NR

CasePreviousTesting: target-region capture sequencing and second-generation high throughput sequencing were performed to analyze all exons and their Flanking regions. Rare and known variants were validated using Sanger sequencing and cascade screening was carried out for all available relatives

Genotyping Method: target-region capture sequencing and second-generation high throughput sequencing, Sanger sequencing and cascade screening.

FunctionalAnalysis:NR

Variant: NM_000256.3:c.1827dupC, NM_004415.4:c.1324T>C

ClinVar:NR

CAID:UnregisteredVariant

gnomAD:NR

Case2: 16-year-old male patient

DiseaseAssertion: monomorphic VT

FamilyInfo:NR

ParentalTesting:NR

CasePresentingHPOs:HP:0031676, HP:0033118, HP:0032643

CaseHPOFreeText: Moderately decreased right ventricular (RV) function and moderate RV dilation. moderate myocyte hypertrophy with mild to moderate interstitial fibrosis and rare adipose tissue. Cervical, mediastinal, abdominal, and pelvic FDG-avid lymphadenopathy. myocyte hypertrophy with patchy interstitial fibrosis.

CaseNotHPOs: NR

CaseNotHPOFreeText:NR

CasePreviousTesting:NR

Genotyping Method:NR

FunctionalAnalysis:NR

Variant: NM_001005242.3:c.148_151del

ClinVar: 45028

CAID: CA011079

gnomAD:NR

AdditionalInfo:NR

Case3: 39-year-old man

DiseaseAssertion: seronegative rheumatoid arthritis

FamilyInfo: Father was diagnosed with hypertrophic cardiomyopathy

ParentalTesting: Genetic testing revealed a pathogenic MYBPC3 variant in the patient and his father (c.655G>C [p.Val219Leu])

CasePresentingHPOs: HP:5210340, HP:0006682, HP:0031971

CaseHPOFreeText: Rccentric septal hypertrophy with a maximal wall thickness of 1.7 cm, no evidence of outflow tract obstruction, and an LV EF of 65% to 70%. Rare premature ventricular complexes. Mild mediastinal lymphadenopathy, pulmonary sarcoidosis

CaseNotHPOs: NR

CaseNotHPOFreeText: NR

CasePreviousTesting: NR

Genotyping Method: NR

FunctionalAnalysis: NR

Variant: NM_006252.4(PRKAA2):c.148_151del (p.Gln50fs)

ClinVar:4891957

CAID:NR

gnomAD:NR

AdditionalInfo:NR

PMID:42233912

Gene:MYBPC3, FLNC, PKP2

HGNC ID:7551, 9024, 3756

Case1: 59-year-old male

DiseaseAssertion: frequent premature ventricular contractions

FamilyInfo:Significant for dilated cardiomyopathy with multiple sudden cardiac deaths. His sister’s initial genetic testing panel was negative for pathogenic variants at that time

ParentalTesting:NR

CasePresentingHPOs: HP:0006682, HP:0025169, HP:0004751, HP:5210340

CaseHPOFreeText: Transthoracic echocardiogram (TTE) demonstrated a left ventricular (LV) ejection fraction (EF) of 20%-25% and an LV diastolic diameter of 6.6 cm. revealed bulky mediastinal adenopathy. A transbronchial biopsy of lung parenchyma showed noncaseating granulomas, and ultimately the patient was found to have pulmonary sarcoidosis.

CaseNotHPOs: NR

CaseNotHPOFreeText: NR

CasePreviousTesting:NR

Genotyping Method: NR

FunctionalAnalysis: NR

Variant:NM_001458.5(FLNC):c.4737+5G>A

ClinVar: 934656

CAID: CA1139660256

gnomAD: NR

AdditionalInfo: NR

PMID:17347475

Gene:MYOZ2

HGNC ID:1330

Case#: Pedigree I-1; 74-year-old Korean male; admitted for dyspnea (NYHA III), palpitations, and bilateral pitting leg edema over several months

DiseaseAssertion: Idiopathic restrictive cardiomyopathy (RCM) with biatrial enlargement, in a family with MYBPC3-related cardiomyopathy

FamilyInfo: Family history of heart disease with two affected daughters (II-2 and II-4), both heterozygous for the same variant and both diagnosed with HCM. Unaffected granddaughter (III-3) tested negative. Both daughters showed asymmetric septal hypertrophy on TTE (18 mm and 17 mm) with mildly dilated LA; daughter II-2 had grade I diastolic dysfunction and mild exertional chest discomfort. CMR confirmed reverse septal curvature hypertrophy consistent with HCM in both daughters, with no LGE in either.⁠

ParentalTesting: Not performed; the proband is the index case in generation I; his parents were not evaluated. Phase established only through the daughters and granddaughter.

CasePresentingHPOs:HP:0002094; HP:0001962; HP:0001677; HP:0001635; HP:0001639; HP:0001698

CaseHPOFreeText: Exertional dyspnea NYHA class III, palpitations, and bilateral leg pitting edema for several months; dyspnea refractory to heart failure medication, with pulmonary venous congestion. ECG and Holter: atrial fibrillation with rare premature ventricular complexes. TTE: RCM with biatrial enlargement and small pericardial effusion. CMR: normal LV chamber size, borderline diffuse LV hypertrophy, very large atria, extensive transmural LGE in the apical wall and mid-myocardial patchy LGE in the ventricular septum. Coronary angiogram normal; no secondary cause of RCM found.⁠

CaseNotHPOs: HP:0000822; HP:0000819; HP:0001658; HP:0001678

CaseNotHPOFreeText: Coronary angiogram normal, so no obstructive coronary disease. No secondary cause of RCM identified; no inflammatory, infiltrative, or systemic disease found. No AV block; the rhythm disturbance was atrial fibrillation.

CasePreviousTesting: Whole exome sequencing (Agilent SureSelect XT Human All Exon v5, Illumina HiSeq2500, GATK. Sanger sequencing of family members showed only the MYBPC3 variant tracked with disease; the other four (KALRN c.1702C>T, KCNH2 c.442C>T, SKI c.30T>G, TTN c.54293T>C) did not correlate with phenotype.⁠

Genotyping Method: WES in the proband, with annotation via dbNSFP and Ensembl VEP; Sanger sequencing confirmed the MYBPC3 frameshift in the proband (I-1), daughters II-2 and II-4, and its absence in granddaughter III-3 (Fig. 3B).⁠

FunctionalAnalysis: None performed. CMR showed extensive LGE in the apical LV, and the authors propose that advanced myocardial fibrosis in end-stage HCM can provoke myocardial atrophy, explaining the relatively normal LV chamber size with a predominantly restrictive phenotype hypothesis.⁠

Variant: MYBPC3 NM_000256.3:c.3313_3314insGG (p.Ala1105Glyfs*85); heterozygous frameshift insertion; absent from gnomAD and the Korean Reference Genome Database.

ClinVar: 1473634

CAID: Not reported.

Gene:MYBPC3

HGNC: HGNC: 7551

PMID: 33803538

gnomAD: Absent per the authors' check of gnomAD as of 8 November 2020, and absent from KRGDB.

AdditionalInfo: Authors conclude the MYBPC3 frameshift is the pathogenic variant, with the same allele producing RCM in the proband and HCM in both daughters; an example of pleiotropy and variable expressivity within one family. The frameshift has previously been reported in Korean HCM. Poor-prognosis features in RCM cited by the authors: male sex, age over 70, high NYHA class, and LA dimension >60 mm.

Case#: P16, 17 year old male

DiseaseAssertion: left ventricular noncompaction cardiomyopathy

FamilyInfo: His mother, sister, and grandfather on his mothers side also had LVNC

ParentalTesting: NR

CasePresentingHPOs: NR

CaseHPOFreeText: The patient had an abnormal structure in the left side of his heart. His heart ultrasound showed extra muscle ridges and deep spaces in the heart muscle.

CaseNotHPOs: NR

CaseNotHPOFreeText: The study did not report fainting, heart rhythm problems, blood clots, or heart failure for this patient.

CasePreviousTesting: Heart ultrasound, ECG, heart MRI, blood tests, and genetic testing.

Genotyping Method: Next generation sequencing followed by Sanger sequencing to confirm this gene change

FunctionalAnalysis: NR

Variant: NM_005159.5:c.329>T

Clinvar: 2137647

CAID: CA391631478

gnomAD: Exact frequency not provided

AdditionalInfo: The patient's heart pumping ability was 70 %on ultrasound. Researchers classified his ACTC1 variant as a variant of uncertain significance meaning they were not sure whether it causes diseases.

Case#: 33 year-old female; first cardiologic evaluation at age 24 (LV wall thickness 13 mm); re-evaluated at 33 after recurrent palpitations

DiseaseAssertion: Noonan syndrome (PTPN11) with sarcomeric hypertrophic cardiomyopathy (MYBPC3); non-obstructive HCM, mild phenotype

FamilyInfo: Father carries the MYBPC3 c.1790G>A variant and has HCM; the PTPN11 variant was absent in both parents, consistent with de novo. Both parents and the proband's brothers underwent full cardiologic evaluation, no cardiovascular disease in the other family members. Parents declined genetic testing of the underage siblings. Grandparents (I-1, I-2) and II-2, II-3 have unknown phenotypes (pedigree Fig. 2).

ParentalTesting: Both parents genotyped for the two proband variants (Table 1). Father heterozygous for MYBPC3 c.1790G>A; neither parent carries PTPN11 c.1510A>G, supporting de novo status. Phase between the two variants therefore established as in trans (different genes).

CasePresentingHPOs: HP:0001639; HP:0001962; HP:0004322; HP:0000271; HP:0001647; HP:0000508

CaseHPOFreeText: Regular psychophysical development. First echo at 24 showed mild increase in LV wall thickness (13 mm). At 33, presented with several episodes of palpitations; exam showed mild facial dysmorphisms (wide mouth, sloping forehead, prominent nasal bridge, prominent nose, low-set ears), short stature, and a systolic heart murmur. Echo: asymmetric LV hypertrophy, maximum wall thickness 16 mm at the anterior interventricular septum, mild mitral regurgitation, non-obstructive. No other cardiovascular signs.

CaseNotHPOs: HP:0001635; HP:0001650; HP:0001642; HP:0001250

CaseNotHPOFreeText: No heart failure, no LV outflow obstruction, no pulmonary stenosis, no other congenital heart defect. No intellectual disability; psychophysical development was regular. No other signs of cardiovascular disease on examination.

CasePreviousTesting: NGS panel of 325 cardiomyopathy-associated genes (Supplementary Table S1); MAF threshold 5%; variants validated by Sanger sequencing; cascade testing restricted to the two proband variants.

Genotyping Method: NGS targeted panel (Maxwell 16 DNA extraction, Agilent Alyssa analysis, Illumina Variant Interpreter, in-house pipeline) with Sanger validation; parental Sanger genotyping for the same two variants.

FunctionalAnalysis: None performed by the authors. They cite prior HeLa cell work showing the MYBPC3 c.1790G>A change causes exon 18 inclusion in the transcript and an almost undetectable 248 bp product.

Variant 1: PTPN11 NM_002834.3:c.1510A>G (p.Met504Val); heterozygous missense; de novo; classified pathogenic, explains Noonan syndrome

ClinVar: Not stated in the paper; verify the current record before submitting.

CAID: N/A

gnomAD: Not reported in the paper; I have not checked gnomAD for this variant.

Variant 2: MYBPC3 NM_000256.3:c.1790G>A (p.Arg597Gln); heterozygous missense; exon 18, last nucleotide of the exon, affecting a highly conserved residue and causing a splicing variation; inherited from the father

ClinVar: Not stated in the paper; authors note it is classified pathogenic/likely pathogenic for HCM in several genetic databases.

CAID: N/A

gnomAD: N/A

PMID: 32824488

Gene: MYBPC3

AdditionalInfo: Authors describe this as the first reported young adult with HCM and mild NS carrying variants in both PTPN11 and MYBPC3. Note the terminology problem: the abstract calls them "compound heterozygous," but the variants are in different genes on different chromosomes, so this is digenic (double heterozygosity), not compound heterozygosity. The authors argue the mild phenotype contrasts with the usual expectation that multiple sarcomeric hits worsen the disease, and that red flags justified the broad panel.

Case#:a 40-year-old woman with a history of hypokinetic-dilative cardiomyopathy and heterozygous for TNNT2 gene mutation

DiseaseAssertion:hypokinetic-dilative cardiomyopathy

FamilyInfo: her family appreciated the clear communication, and as her condition improved without further complications, she expressed gratitude for the care provided.

ParentalTesting:n/r

CasePresentingHPOs:HP:0001644, HP:0002094, HP:0002094, HP:0001695,

CaseHPOFreeText:Progressive dyspnea and fatigue began in January 2017. In February 2018, the patient had cardiac arrest due to ventricular fibrillation at 26 weeks’ gestation, followed by emergency caesarean section. She carried a heterozygous TNNT2 variant (c.547C>T, p.Arg183Trp)

CaseNotHPOs: HP:0031972, HP:0031972

CaseNotHPOFreeText:Coronary angiography showed no significant stenosis.

CasePreviousTesting:Testing method and scope

GenotypingMethod:n/a

FunctionalAnalysis:not reported

Variant: c.547C>T p.Arg183Trp)

Clinvar:not known

CAID:CA391630526

gnomAD:n/r

AdditionalInfo:n/r

PMID : 40008267

Gene: TNNT2

HGNC ID: 11949

PMID: 29367541

Gene: TNNT2

HGNC ID: 11949

Case#: 64-year-old male, non-smoker, first admitted June 2014; Russian family; died 2019 at age 69

DiseaseAssertion: MYBPC3-related cardiomyopathy with a predominantly restrictive phenotype in combination with left ventricular noncompaction (LVNC) and cardiac sarcoidosis

FamilyInfo: Son (39) and daughter (35) both heterozygous for the same variant and both have non-obstructive asymmetric HCM, with no LVNC on cardiac CT; both essentially asymptomatic on beta-blocker monotherapy. Five-year SCD risk 4.82% (son) and 2.07% (daughter); ICD implanted in the son, no shocks in three years. Authors mention another family of theirs with a father who died suddenly young and children with HCM and LVNC.

ParentalTesting: Not performed; the proband is the index case; his parents were not evaluated. Transmission to both children confirmed by Sanger.

CasePresentingHPOs:HP:0001639

CaseNotHPOs: N/A

CasePreviousTesting: N/A

Genotyping Method: Next-generation sequencing panel; variants confirmed by Sanger.

FunctionalAnalysis: N/A

Variant 1: MYBPC3 NM_000256.3:c.278delA; heterozygous frameshift

Variant 2: KCNJ5 c.464G>A; heterozygous missense

ClinVar: N/A

CAID:N/A

gnomAD: N/A

Gene:MYBPC3

PMID:36011256

PMID:39905734

Gene:TNNT2

HGNC ID:11949

Case#: a 50‐year‐old male who was clinically diagnosed with isolated CS and prescribed with prednisolone without much effect, and subsequent genetic analysis revealed pathogenic variants in LMNA and TNNT2, representative genes for cardiomyopathy.

DiseaseAssertion:Dilated cardiomyopathy

FamilyInfo: not reported

ParentalTesting: He had no family history of heart disease or sudden death

CasePresentingHPOs:HP:0002094,HP:0005110,HP:0025169, HP:0005110

CaseHPOFreeText:Progressive cardiac conduction disease: first-degree AV block with left axis deviation on an earlier ECG progressed to high-grade and then complete AV block. At age 50, the patient also had mild dyspnoea on exertion (New York Class ll) and atrial fibrillation. The authors later stated that it was dilated cardiomyopathy.

CaseNotHPOs:HP:0033608,HP:0002716

CaseNotHPOFreeText:CT showed no enlarged lymph nodes, pulmonary nodules, or other organ abnormalities

CasePreviousTesting: whole‐exome sequencing analysis to evaluate the risk of inherited cardiomyopathies and identified two missense variants in TNNT2 (chr1:201364335(hg38), NM_001001430.3, c.422G>A, p.Arg141Gln) and LMNA (chr1:156136096(hg38), NM_170707.4, c.1132A>C, p.Lys378Gln) (Figure 3). Sanger sequencing analysis identified a heterozygous single‐base substitution (c.1132A>C) in the LMNA gene and c.422G>A in the TNNT2 gene (red arrows).

Genotyping Method:Whole-exome sequencing (WES) identified the variants; Sanger sequencing of the TNNT2 and LMNA variants is shown in Figure 3.

FunctionalAnalysis:Not reported

Variant:TNNT2: NM_001001430.3:c.422G>A (p.Arg141Gln),LMNA: NM_170707.4:c.1132A>C (p.Lys378Gln)

ClinVar:43637

CAID:CA004540

gnomAD:not reported

AdditionalInfo:not reported

PMID: 42112275

Gene: MYBPC3

HGNC ID: 7551

Case2: 40 year old Male, 37 year old Female

DiseaseAssertion: HCM, basal septal hypertrophy, dilated phase HCM

FamilyInfo: Family was notable for end stage HCM in father and in younger brother, family history was notable for HCM in grandmother and sudden cardiac death(SDC) due to HCM in mother

ParentalTesting: No parental testing done

CasePresentingHPOs: “Inguinal Hernia surgery, exertional dyspnea”

CaseHPOFreeText: Transthoracic echocardiography unveiled hypertrophy of the interventricular septum and left ventricular anterior wall, systolic anterior motion of the mitral valve

CaseNotHPOs: N/A

CaseNotHPOFreeText: ECG demonstrated a sinus rhythm at 58 bpm with complete right bundle branch block, heart failure progressively worsened

CasePreviousTesting: Cardiac magnetic resonance reveals ring like late gadolinium enhancement(LGE) as a imaging phenotype

Genotyping Method: Cardiac magnetic resonance

FunctionalAnalysis: N/A

Variant: NM_000257.4 c.2302G>A, NM_000256.3 c.2459G>A MANE select

ClinVar: 8617

CAID: CA012326

gnomAD: chr11-47337534

https://reg.clinicalgenome.org/redmine/projects/registry/genboree_registry/by_canonicalid?canonicalid=CA012326

Case1: 48 year old male

DiseaseAssertion: . Two missense variants in MYBPC3 (NM_000256.3): c.2533C>G in exon 26 (C6 domain) were identified and, classified as a variant of uncertain significance (VUS, score 2), and c.1696T>A in exon 18 (C4 domain), a VUS with a score of 5.

FamilyInfo: There was no family history of cardiomyopathy or SCD.

ParentalTesting: NR

CasePresentingHPOs: HP:0004751, HP:0006682, HP:0001712

CaseHPOFreeText: 38 year old man, suffering from contractions, and one short run of non-sustained ventricular tachycardia lasting four beats. Asymmetric septal hypertrophy with a maximum thickness of 19 mm. In addition, marked biatrial enlargement was evident, with a left atrial volume index of 79 mL/m² and right atrial area of 25 cm². Importantly, extensive diffuse late gadolinium enhancement (LGE) was detected in the basal and mid-septal and anterior segments, involving 17% of the myocardial mass

CaseNotHPOs: NR

CasePreviousTesting: genetic testing was performed using the Health in Code HCM panel, which includes the following 18 genes: ACTC1, DES, FHL1, FHOD3, GLA, LAMP2, MYBPC3, MYH7, MYL2, MYL3, PRKAG2, PTPN11, TNNC1, TNNI3, TNNT2, TPM1, TRIM63, and TTR.

Genotyping Method: Health in Code HCM panel

FunctionalAnalysis:

Variant: NM_000256.3:c.2533C>G, NM_000256.3:c.1696T>A

ClinVarID:180973, 915724

CAID:CA380324353, CA012504

gnomAD:

AdditionalInfo:NR

PMID: 28815794

Gene: TNNT2

HGNC ID: 11949

Case#: Pedigree III:2; male; HCM diagnosed clinically at age 39 (1998); heart transplant after progression to end-stage heart failure

DiseaseAssertion: Hypertrophic cardiomyopathy (HCM), progressed to end-stage heart failure with systolic dysfunction

FamilyInfo: No family history of heart disease reported at diagnosis; no known consanguinity. Parents deceased and unavailable for testing. 12 relatives genotyped: one brother (III:3) homozygous, seven first- and second-degree relatives heterozygous. All heterozygotes have normal ECG, normal echo, and no cardiac symptoms. Three children of generation IV (IV:7, IV:8, IV:9) still awaiting results.⁠

ParentalTesting: Not performed; both parents deceased. Absence of consanguinity stated but not genetically confirmed; parental phase therefore inferred rather than tested.

CasePresentingHPOs: HP:0001639; HP:0002094 (Dyspnea); HP:0001658; HP:0001678

CaseHPOFreeText: Exertional dyspnea at age 39 with systolic murmur; IVS 26 mm, posterior wall >16 mm, LVOT peak velocity 2.8 m/s. Pacemaker 1999, extracted 2010 for infection. 2013 circumflex occlusion treated with stent (cholesterol 6.8 mmol/L, LDL 4.6 mmol/L; former smoker). Septum 27 mm, moderate systolic dysfunction, NSVT on Holter → ICD. 2014 AF with severe dyspnea; on beta-blocker, ACE inhibitor, and aldosterone antagonist. 2016 VO₂max 14 mL/kg/min; LVEDP 24 mmHg rising to 38 with exercise, pulmonary pressure 56/27 rising to 70/… systolic. Biopsy: moderate interstitial fibrosis, focal hypertrophy and atrophy, no infiltrative disease.

CaseNotHPOs: HP:0000822; HP:0000819

CaseNotHPOFreeText: BP normal throughout, no hypertension. No storage or infiltrative disease on biopsy. Spirometry normal. Narrow QRS, so CRT not indicated.

CasePreviousTesting: 84-gene cardiomyopathy NGS panel (MYBPC3 100% coverage); MLPA confirmed true homozygosity rather than hemizygous deletion; Sanger cascade in 12 relatives.

Genotyping Method: NGS panel followed by MLPA confirmation of homozygosity; Sanger for family cascade.

FunctionalAnalysis: None performed. Biopsy showed interstitial fibrosis with hypertrophy and atrophy, no infiltrative disease. Dominant-negative mechanism proposed, untested.

Variant: MYBPC3 NM_000256.3:c.2618C>A (p.Pro873His); homozygous missense; C7 domain. (Paper writes "c.2618 G>A" once, C>A is correct.)

ClinVar: Not stated; conflicting interpretations noted in the literature. Pepper please verifiy for me!

CAID: N/A

gnomAD: AF 0.00006781 (14/206,446; 13/97,288 European non-Finnish) per the authors.

AdditionalInfo: ACMG Class 2 (likely pathogenic) heterozygous. Authors argue homozygosity drove progression to end-stage failure; alternative triggers considered, prior myocarditis (1989) and the 2013 infarct; but judged insufficient to explain severity.

PMID: 29663722 Gene: MYBPC3 HGNC: HGNC:7551

PMID:20973921

Gene:TNNT2

HGNC ID:11949

Case#:A 70‐year‐old woman, previously healthy with a left ventricular ejection fraction presented with DCM

DiseaseAssertion:dilated cardiomyopathy and a 4-month history of progressive heart failure

FamilyInfo:"Family history was negative for IDC or heart failure (Figure 3), although an uncle (II‐3) reportedly had an enlarged heart, and three other relatives (II‐1, II‐2, and III‐4) had cardiac related deaths confirmed by death certificate. The proband’s father (II‐1) died of myocardial failure and pulmonary edema; her mother (II‐2) died of pulmonary embolism; and her sister (III‐4) died suddenly of coronary artery disease in her 60s. Her daughter, the proband’s niece (IV‐3), had a history of palpitations and lower extremity swelling, intermittent numbness, and blanching of the fingers at age 49. Her echocardiogram was normal. Her ECG showed nonspecific ST‐T wave changes and left anterior hemiblock."

ParentalTesting:no parental testing reported because both parents were deceased. The two offsprings that were reported were tested and carried both variants.

CasePresentingHPOs:HP:0001644, HP:0001635, HP:0002875, HP:0012378

CaseHPOFreeText:symptoms of progressive dyspnea on exertion and fatigue that began 2–3 months prior to her presentation. Also, she had an unrelenting progression of symptoms and was hospitalized with advanced NYHA Class IV heart failure 6 weeks later. Lastly, she received a heart transplant.

CaseNotHPOs:not reported

CaseNotHPOFreeText:no myocarditis or infiltrative process and no histological evidence of hemochromatosis,

CasePreviousTesting:Oligonucleotide hybridization‐based DNA sequencing was conducted in the proband for a panel of 19 DCM genes ( Table 1 )

Genotyping Method:Oligonucleotide hybridization‐based DNA sequencing and genomic DNA was extracted from whole blood and was sequenced in our laboratory in both directions to detect and/or confirm nucleotide variants in TNNT2 in the proband and the proband’s relatives using an Applied Biosystems 3130XL capillary sequencer

FunctionalAnalysis:R139H (Figure 4): Functional studies in porcine cardiac skinned fibers reconstituted with the mutant R139H troponin T protein showed decreased Ca2+ sensitivity at pH 7, characteristic of DCM.

Variant:416G>A (R139H) in exon 10 and 690–6G>A in intron 13.

ClinVar:not found

CAID:CA004513

gnomAD:not found

AdditionalInfo:not reported

case1: male, 40 weeks,

DiseaseAssertion: sudden-onset acute heart failure

FamilyInfo: Both parents suspected of being heterozygous carriers of a pathogenic MYBPC3 variant

ParentalTesting: Both parents were identified as heterozygous carriers of a pathogenic MYBPC3 variant

CasePresentingHPOs: HP: 0001639, HP: 0001631, HP: 0001635

“Hypertrophic cardiomyopathy, atrial septal defect, acute heart failure”

CaseHPOFreeText: Absence of significant interstitial fibrosis, extensive myocardial disarray and contraction band necrosis

CaseNotHPOs: N/A

CaseNotHPOFreeText: normal fetal growth and anatomy reported

CasePreviousTesting: Targeted gene panel for pathogenic variants in MYBPC3

Genotyping Method: Whole-exome sequencing (WES)

FunctionalAnalysis: N/A

Variant: NM_000256.3:c.2905+1G>A

Case6: 48 year old male

DiseaseAssertion: Carried the MYBPC3 E619K mutation

FamilyInfo:Three unaffected children were examined (IV:1, IV:2 and IV:3), all with normal echocardiography without signs of hypertrophy or dilatation. Both affected individuals as well as a 26-year-old unaffected daughter (M29, IV:3) carried the MYBPC3 E619K mutation

ParentalTesting:NR

CasePresentingHPOs: HP:0034307, HP:0012666, HP:0011713, HP:0001635

CaseHPOFreeText: Onset of symptoms in their third decade; the index case required heart transplantation 3 years after the onset of symptoms. Has onset at the age of 37. Has left ventricular end diastolic diameter (in mm and indexed by body surface area (cm/m2)) with the value of 79 mm and 3.2 cm/m2. They have a 20% of left ventricular ejection fraction. ECG as left bundle branch block. Clinical status as DCM/ congestive heart failure. CAG as normal.

CaseNotHPOs:NR

CaseNotHPOFreeText:NR

CasePreviousTesting:NR

Genotyping Method:Genetically screened, also using GenBank with PCR by amplifying the coding region

FunctionalAnalysis:NR

Variant: NM_000256.3:c.1855G>A

ClinVar:161303

CAID:CA011336

gnomAD: gnomAD v2: 11:47362731 C / T gnomAD v3: 11:47341180 C / T gnomAD v4: chr11-47341180-C-T

AdditionalInfo:NR

Case5: 65 year-old male

DiseaseAssertion: carried a known TNNT2 K247R mutation as well as two novel intronic variants in MYH7 (IVS39+7C>A) and MYBPC3 (IVS25+13T>A)

FamilyInfo: None of his five siblings were affected, judged by their clinical presentation, nor was there any history of cardiac disease or sudden death in the family.

ParentalTesting:NR

CasePresentingHPOs:HP:0003677, HP:0012828, HP:0001635, HP:0005110, HP:0034307, HP:0012666,

CaseHPOFreeText: had late-onset at age 47 IDC, with a slow progression to severe heart failure and subsequently HTX. He also suffered from atrial fibrillation in the later stages of his disease. Had left ventricular end diastolic diameter (in mm and indexed by body surface area (cm/m2)) with a value of 68mm and 3.4cm/m2. As well with 30% of left ventricular ejection fraction. His ECG is normal, clinical status is heart transplantation from the age of 56. CAG is normal.

CaseNotHPOs:NR

CaseNotHPOFreeText:NR

CasePreviousTesting:NR

Genotyping Method:Genetically screened, also using GenBank with PCR by amplifying the coding region

FunctionalAnalysis: The variant could thus possibly result in the synthesis of a limited amount of the slightly modified β-myosin. The functional significance of this is not easily established, but it suggests that the variant may be a disease modifier.

Variant:NM_001276345.2:c.869A>G

ClinVar:4881578

CAID:CA344201883

gnomAD:NR

AdditionalInfo: MYH7 (IVS39+7C>A) increased the likelihood of a cryptic donor splice site to 70%, possibly resulting in the synthesis of mRNA coding for a β-myosin with a C terminus of –VGLE instead of –GLNEE. As the variant is located in the last exon, the faulty spliced mRNA is probably not degraded but results in the synthesis of a modified protein.

Case4: 47 year old male

DiseaseAssertion: Carried the MYBPC3 R326Q mutation

FamilyInfo:His father had onset of symptoms at 77 years of age and is stable on medication. Two asymptomatic young children (M21, III:1 and :2) had no signs of hypertrophy or dilatation on echocardiography and normal ECG.

ParentalTesting: NR

CasePresentingHPOs: HP:0011713, HP:0034307, HP:0012665, HP:0001635

CaseHPOFreeText: Had onset of symptoms at 42 years, LBBB on ECG and required cardiac resynchronization therapy. Has left ventricular end diastolic diameter (in mm and indexed by body surface area (cm/m2) of 81 mm and 3.6 cm/m2. A left ventricular ejection fraction as 20%. ECG as left bundle branch block. Clinical status as DCM/ congestive heart failure. CAG as normal. As well with cardiac resynchronization therapy.

CaseNotHPOs: HP:0011675

CaseNotHPOFreeText: No arrhythmia

CasePreviousTesting:NR

Genotyping Method:Genetically screened, also using GenBank with PCR by amplifying the coding region

FunctionalAnalysis: It results in the replacement of a conserved charged arginine with neutral glutamine at residue 326 in the phosphorylatable MyBPC motif of cMyBPC. This charge change is likely to cause functional impairment.

Variant:NM_000256.3:c.977G>A

ClinVar:42813

CAID:CA016212

gnomAD: gnomAD v2: 11:47367871 C / T gnomAD v3: 11:47346320 C / T gnomAD v4: chr11-47346320-C-T

AdditionalInfo:NR

Case 3: A 64 year old female

DiseaseAssertion: The case carried the novel MYH7 K637E mutation

FamilyInfo: Her mother died of a suspected but unconfirmed cardiac cause; thus, this was regarded as a non-FDC case. Two healthy sisters declined participation in the study.

ParentalTesting:NR

CasePresentingHPOs: HP:0003674, HP:0034307, HP:0002372, HP:0011675, HP:0005110

CaseHPOFreeText: Slowly from onset of symptoms at the age of 42 years, and received HTX in her sixth decade. Has left ventricular end diastolic diameter (in mm and indexed by body surface area (cm/m2)), 81mm and then 4.2m2. LVEF as 15%, ECG as normal. Arrhythmia as atrial fibrillation. NYHA as 4. Clinical status as heart transplantation. CAG has a normal level.

CaseNotHPOs:NR

CaseNotHPOFreeText:NR

CasePreviousTesting:NR

Genotyping Method: Genetically screened, also using GenBank with PCR by amplifying the coding region

FunctionalAnalysis: NR

Variant:NM_000257.4:c.1909A>G

ClinVar:1329402

CAID:CA389049558

gnomAD:NR

AdditionalInfo:NR

Case1: 13 year old female

DiseaseAssertion: LVNC

FamilyInfo: No family history of cardiac disease

ParentalTesting:

CasePresentingHPOs: HP:0011664. HP:0002094. HP:0001279. HP:0031295

CaseHPOFreeText:Left Ventricular noncompaction, Dyspnea (shortness of breath), Fainting, Left atrial enlargement

CaseNotHPOs:HP:0000929. HP:0001712

CaseNotHPOFreeText:Abnormal skull morphology, left ventricular hypertrophy

CasePreviousTesting:

Genotyping Method:Next-Generation Sequencing (NGS)

FunctionalAnalysis:

Variant:c.575G>A

ClinVar:12424

CAID:CA021957

gnomAD:

AdditionalInfo:

PMID: 30279906

Gene: TNNI3

HGNC ID: 11947

PMID: 20641121

Gene: MYL3

HGNC ID: HGNC:7584

Case1:Female diagnosed at 28

DiseaseAssertion:HCM, ASH, LVEF

FamilyInfo:Sister with HCM, ASH, and mid-LV cavity obstruction

ParentalTesting:

CasePresentingHPOs:HP:0001639, HP:0001670, HP:0034314, HP:0001279

CaseHPOFreeText:Hypertrophic cardiomyopathy, Asymmetric Septal Hypertrophy, Abnormal Left Ventricular Ejection Fraction, Syncope

CaseNotHPOs:

CaseNotHPOFreeText:

CasePreviousTesting:

Genotyping Method:Not detailed

FunctionalAnalysis:MYL3 A57G

Variant:c.170C>G (p.Ala57Gly)

ClinVar:31780

CAID:CA013589

gnomAD:

AdditionalInfo:

Case#: 30 year old female athlete

DiseaseAssertion: Subclinical hypertrophic cardiomyopathy

FamilyInfo: Her mother has HCM and the same ACTC1 gene change. Her grandmother and uncle on her mothers side died suddenly.

ParentalTesting: Her mother tested positive for the ACTC1 gene change and there isn't any information about the father.

CasePresentingHPOs: NR

CaseHPOFreeText: The patient did not have dizziness, fainting, trouble breathing or chest pain. Her heart muscle was not thickened.

CaseNotHPOs: NR

CaseNotHPOFreeText: The patient sometimes felt her heart beating unusually during exercise. A heart MRI showed small changes in her heart muscle and heart valve.

CasePreviousTesting: The patient had an ECG, heart ultrasound, heart monitor and heart MRI

Genotyping Method:Sanger sequencing was used to test the ACTC1 gene.

FunctionalAnalysis: NR

Variant: ACTC1 p.Val11Leu

Clinvar: 2947021

CAID: CA391633409

gnomAD: NR

AdditionalInfo: The patient continued playing competitive sports and had regular heart checkups.

Case1:19 Year-old male

DiseaseAssertion:HCM

FamilyInfo:None documented

ParentalTesting:

CasePresentingHPOs:HP:0001639

CaseHPOFreeText:Hypertrophic Cardiomyopathy

CaseNotHPOs:

CaseNotHPOFreeText:

CasePreviousTesting:

Genotyping Method:Next Generation Sequencing

FunctionalAnalysis:

Variant:c.442G>A, (p.Gly148Arg)

ClinVar:42752

CAID: CA015105

gnomAD:

AdditionalInfo:

PMID: 31293105

Gene: MYBPC3

HGNC ID: HGNC:7551

Whole genome sequencing in paediatric channelopathy and cardiomyopathy

PMID: 38586174 Gene: MYBPC3 HGNC ID: 7551

Case2: 12-year-old boy (Patient 2) DiseaseAssertion: DCM FamilyInfo: Family history unremarkable. ParentalTesting: The MYBPC3 variant was inherited from his father. The father’s cardiac phenotype is not reported. CasePresentingHPOs: HP:0001644, HP:0003546 CaseHPOFreeText: Severely depressed biventricular function; heart transplantation for decompensated heart failure. CaseNotHPOs: CaseNotHPOFreeText: CasePreviousTesting: Previous WES was negative; the variant’s intronic region was not adequately covered. Genotyping Method: Whole-genome sequencing (WGS; Illumina NovaSeq 6000; aligned to hg19/GRCh37). FunctionalAnalysis: SpliceAI predicted a potential splicing effect; no functional assay in this patient is reported. Variant: NM_000256.3:c.1224-80G>A (heterozygous intronic variant) ClinVar: 693982 CAID: CA221697326 gnomAD: 0.0000637 AdditionalInfo: The authors classified the variant as a VUS in this DCM case because evidence for a MYBPC3–DCM relationship is limited. ClinVar currently reports a pathogenic/likely pathogenic aggregate classification, primarily in relation to HCM. Reanalysis found no second MYBPC3 variant.

Case#: Family 1, individual II-5

DiseaseAssertion: Dilated cardiomyopathy

FamilyInfo: The proband has a family history of DCM. His father and brother also had DCM and died from heart failure at ages 69 and 63 respectively. The disease follows an autosomal dominant inheritance pattern.

ParentalTesting: Want reported, his father had DMC but this article does not confirm genetic testing of his parents.

CasePresentingHPOs: Dilated cardiomyopathy (HP:0001644) & left ventricular systolic dysfunction (HP:0005162)

CaseHPOFreeText: The proband was diagnosed with DCM at age 45 and received medication for heart failure. At the time of the study he was 66 years old. His echocardiogram showed an enlarged left ventricle and reduced heart function with an ejection fraction of 33%.

CaseNotHPOs: NR

CaseNotHPOFreeText: The researchers reported no other structural heart diseases or conditions contributing to DCM in the affected family members, including coronary heart disease, valvular heart disease, viral myocarditis and hypertension.

CasePreviousTesting: ECG, clinical examination and routine laboratory testing were part of the study assessment. The probands echocardiogram showed a left ventricular end diastolic diameter of 63 mm and an ejection fraction of 33%.

Genotyping Method: Genome wide microsatellite screening, genetic linkage analysis, whole exome sequencing and sanger sequencing.

FunctionalAnalysis: Laboratory experiments showed that the KLF13 E144X mutation reduced the proteins ability to activate the heart related genes ACTC1 and MYH7. The mutation also affected DNA binding cooperation with GATA4 and normal nuclear localization.

Variant: KLF13 c.430G >T

Clinvar: NR

CAID: CA391891162

gnomAD: The researchers reported that the variant was absent from gnomAD and other population databases at the time of their study. No numerical allele frequency was provided.

AdditionalInfo: The proband is a male from a 4th generation Chinese family. His KLF13 mutation was associated with familial DCM. the researchers found that the mutation was shared by affected family members and was absent from unaffected family members and 418 unrelated healthy controls.

Case#: Family 2, III-10 47 year old female

DiseaseAssertion: Dilated cardiomyopathy

FamilyInfo: Multiple family members had DCM. The disease followed an autosomal dominant inheritance pattern.

ParentalTesting: NR

CasePresentingHPOs: Dilated cardiomyopathy (HP:0001644)

CaseHPOFreeText:Female aged 47 with DCM. Her left ventricular end diastolic diameter was 57mm and her ejection fraction was 40%.

CaseNotHPOs: NR

CaseNotHPOFreeText: NR

CasePreviousTesting: Echocardiogram and clinical cardiac evaluation.

Genotyping Method: Sanger sequencing of KLF13

FunctionalAnalysis: The E194X mutation reduced the ability of KLF13 to activate ACTC1 and MYH7 and bind their promoters. It also disrupted cooperation with GATA4.

Variant: KLF13 c.580G>T

Clinvar: NR

CAID: NR

gnomAD: The variant was reported as absent from gnomAD at the time of the study.

AdditionalInfo: The mutation was found in affected family members and was absent from 418 unrelated healthy controls.

Case#: Family 3, III-4

DiseaseAssertion: Dilated cardiomyopathy

FamilyInfo: The family had multiple cases of DCM consistent with autosomal dominant inheritance.

ParentalTesting: NR

CasePresentingHPOs: Dilated cardiomyopathy (HP:0001644)

CaseHPOFreeText: Female age 41 with DCM. her left ventricular end diastolic diameter was 58 mm and her ejection fraction was 43%.

CaseNotHPOs: NR

CaseNotHPOFreeText: NR

CasePreviousTesting: Echocardiogram and clinical cardiac evaluation

Genotyping Method: Sanger sequencing of KLF13

FunctionalAnalysis: The C199R mutation reduced KLF13 ability to activate ATC1 and MYH7 bind DNA and work together with GATA4.

Variant: KLF13 c.595T>C

Clinvar: NR

CAID: CA391512228

gnomAD: The variant was reported as absent from gnomAD at the time of the study.

AdditionalInfo: The variant was associated with familial aDCM and was not detected in the 418 healthy controls.

PMID: 22194935

Gene: MYBPC3

HGNC ID: HGNC:7551

PMID 37498360

Gene: TPM1

HGNC ID: 12010

Case1: HCM patient-derived cell line UKEi070-A (demographics not reported in this paper) DiseaseAssertion: HCM

ParentalTesting: CasePresentingHPOs: HP:0001639 CaseHPOFreeText: CaseNotHPOs: CaseNotHPOFreeText: CasePreviousTesting: Genotyping Method: Not reported in this paper; it references a previously established patient-derived cell line. FunctionalAnalysis: The variant is reported to cause MYBPC3 protein haploinsufficiency in cardiomyocytes. In this study, TTL overexpression normalized cell hypertrophy in the HCM cell model. Variant: NM_000256.3:c.2308G>A (heterozygous; the paper reports the splice consequence as p.Asp770Serfs98X) ClinVar: 36604 CAID: gnomAD: NR AdditionalInfo: The paper uses patient-derived induced pluripotent stem cell cardiomyocytes; it does not provide the patient’s age, sex, or pedigree.

Chronic Activation of Tubulin Tyrosination Improves Heart Function

PMID: 39279670 Gene: MYBPC3 HGNC ID: 7551

Novel Intragenic PAX6 Deletion in a Pedigree with Aniridia, Morbid Obesity, and Diabetes

PMID: 31361967

Gene: MYBPC3

HGNC ID: 7551

Case1: 50 year old male DiseaseAssertion: HCM; hydroxychloroquine cardiotoxicity FamilyInfo: Six children undergoing predictive testing for the familial MYBPC3 variant; family history not reported ParentalTesting: CasePresentingHPOs: HP:0001639 CaseHPOFreeText: Monomorphic ventricular tachycardia, dyspnea, nausea, vomiting, biventricular hypertrophy, systolic dysfunction, cardiogenic shock CaseNotHPOs: CaseNotHPOFreeText: CasePreviousTesting: Prior CMR showed nonobstructive HCM; cardiomyopathy gene panel identified the variant Genotyping Method: Cardiomyopathy gene panel FunctionalAnalysis: Altered splicing with exon 30 skipping; authors describe a nonfunctional protein or premature stop codon Variant: c.3330+5G>C ClinVar: 42706 CAID: gnomAD: 0.03% (as reported in the article) AdditionalInfo: Long-term hydroxychloroquine exposure for malaria prophylaxis; biopsy findings were consistent with both HCM and hydroxychloroquine cardiotoxicity

Hydroxychloroquine Cardiotoxicity and Sarcomeric Hypertrophic Cardiomyopathy.”

PMID: 40514126 Gene: MYBPC3 HGNC ID: 7551

Case#: 51-year-old Spanish man

DiseaseAssertion: Hypertrophic cardiomyopathy

FamilyInfo: Familial HCM

ParentalTesting:

CasePresentingHPOs: Hypertrophic cardiomyopathy

CaseHPOFreeText: not reported

CaseNotHPOs: not reported

CaseNotHPOFreeText: not reported

CasePreviousTesting: not reported

Genotyping Method: Genetic testing/sequencing

FunctionalAnalysis:

Variant: g.47363647G>A, p.Ala562Val

ClinVar: not found

CAID: CA078267

gnomAD: not found

AdditionalInfo: not reported

PMID: 28265379

Gene: MYBPC3

HGNC ID: 7551

Case:Female, 35. DiseaseAssertion:Hypertrophic cardiomyopathy (HCM) with left ventricular noncompaction (LVNC) and conduction abnormalities. Familyinfo:The patient's father had hypertrophic cardiomyopathy and carried a heterozygous MYBPC3 p.(Pro1066Arg) variant. The patient's mother was also heterozygous for the MYBPC3 variant. The patient had one sister who did not have reported cardiac abnormalities and was heterozygous for the MYBPC3 variant. The family was initially considered non-consanguineous. Genetic analysis identified a 26 Mb region of homozygosity, suggesting distant parental relatedness. ParentalTesting:Both parents were tested. The father and mother were heterozygous for MYBPC3 c.3197C>G (p.Pro1066Arg). The affected daughter inherited the variant from both parents and was homozygous. CasePresentingHPOs:HP:0031992, HP:0001685, HP:0005157, HP:0031295, HP:0001667, HP:0001670, HP:0001712, HP:0005144, HP: 0031195, HP:0030682, HP:0005135, HP: 0006682, HP: 0004763 CaseHPOFreeText:The patient developed severe cardiac manifestations associated with homozygous MYBPC3 p.(Pro1066Arg). Cardiac MRI showed ventricular hypertrophy, myocardial fibrosis, and features of left ventricular noncompaction. At follow-up, imaging showed asymmetric ventricular wall thickness, with a maximum diastolic thickness of 20 mm in the mid-lateral segment. She also had apical hypokinesia and left atrial enlargement. Electrocardiography and Holter monitoring showed premature ventricular complexes and a 20-beat episode of nonsustained ventricular tachycardia. CaseNotHPOs:No specific negative HPO findings were established for the affected daughter in the reported HPO table. CaseNOTHPOFreeText:not reported CasePreviousTesting:Cardiac MRI, echocardiography, electrocardiography, and 24-hour Holter monitoring were performed. Genetic evaluation was also conducted to identify the MYBPC3 and MYH7 variants. GenotypingMethod:Whole-exome sequencing (WES) trio analysis was performed using DNA from the affected daughter and both parents. Family segregation analysis was performed by Sanger sequencing using an Applied Biosystems 3130 sequencer. FunctionalAnalysis:No direct functional analysis of the MYBPC3 variant was reported. Variant:NM_000256.3 (MYBPC3): c.3197C>G; p.(Pro1066Arg). ClinVar:1171602. CAID:not reported gnomAD:not reported AdditionalInfo:The patient was homozygous for the MYBPC3 p.(Pro1066Arg) variant. Both parents carried the variant in the heterozygous state. A 26 Mb region of homozygosity was identified on chromosome 11, supporting the possibility of distant parental relatedness. The variant was initially classified as a variant of uncertain significance and was subsequently reclassified as likely pathogenic following family segregation analysis.

PMID: 32453731

Gene: MYL2

HGNC ID: 7583

Case1: Male, Infant, Tunisian

DiseaseAssertion: infantile-onset HCM and mitral valve dysplasia

FamilyInfo: Family with consanguinity in which four children had died before one year of age. The father (37 years old) and mother (27 years old) of the proband are consanguineously related. Two infants (VI:1 and VI:2) died at less than 30 days of age from cardiorespiratory arrest, and two (VI:3 and VI:4, proband) of them displayed abnormal cardiac findings on chest roentgenogram. While all four children displayed hepatomegaly and general hypotonia, VI:3 and VI:4 had a marked increase in heart size and died from refractory cardiogenic shock. The status of the MYL2 allele in siblings is unknown. The proband (fs/fs) was homozygous for the MYL2-fs allele while the parents were found to be heterozygous (fs/wt) carriers. The father (37 years old) and mother (27 years old) of the proband are consanguineously related, were asymptomatic from a cardiac standpoint and had normal cardiac anatomy and function as evaluated by an echocardiogram

ParentalTesting: Homozygous variant in the proband and that the parents are heterozygous carriers using Sanger DNA sequencing of the genomic region. Father (37 years old) and mother (27 years old) were asymptomatic from a cardiac standpoint and had normal cardiac anatomy and function as evaluated by an echocardiogram

CasePresentingHPOs: HP:0200128, HP:0001653, HP:0002092, HP:0001639, HP:0002240

CaseHPOFreeText: Showed a rapid decline in health and was treated for various periods in neonatal intensive care units. The patient also displayed severe mitral valve regurgitation with abnormal thickening of the mitral valve leaflets and pulmonary arterial hypertension. Post-mortem examination of the proband’s heart confirmed severe biatrial dilatation, significant biventricular hypertrophy with small ventricular cavities and severe mitral valve dysplasia

CaseNotHPOs: NR

CaseNotHPOFreeText: no gross developmental defects

CasePreviousTesting: No prior genetic testing reported before exome sequencing

Genotyping Method: Performed exome sequencing on the proband. Exome libraries were constructed using the Agilent SureSelectQXT Target Enrichment System for Illumina Multiplexed Sequencing Protocol (Agilent Technologies, CA). DNA libraries were captured with the Agilent Clinical Research Exome Kit. Paired-end 150 base pair reads were generated for exome-enriched libraries sequenced on the Illumina HiSeq 4000 to a targeted depth of 100× coverage

FunctionalAnalysis: Functional analysis performed. Immunohistochemical analysis of MYL2 expression in the proband’s ventricular myocardium shows a remarkable reduction in the expression of MYL2 as compared to control. Also, MYL2 mRNA was detected in the ventricle of the proband by RT-PCR. This suggests that the frameshift variant adversely affects the levels of MYL2 protein in the proband. Using immunoblot analysis, we observed that overexpression of the MYL2-fs variant was significantly reduced compared to stop-gain variants and the missense variant. When the H9c2 cells were treated with MG-132 after transfection with the MYL2-fs construct, the GFP signal corresponding to MYL2-fs was recovered. The in vitro experiments indicate that the MYL2-fs variant is not stable and that proteasome-mediated degradation of the translated product plays a key role in the instability of the protein. The overexpression of the fs variant identified in our proband or the MYL2-G162R missense variant failed to rescue the phenotype. Results reported in Figures 2, 3, and 4.

Variant: NM_000432.3:c.431_432delCT

ClinVar: NR

CAID: UnregisteredVariant

gnomAD: NR

AdditionalInfo: 4 siblings who died before 1 year of age but MYL2 genotyping was only confirmed in the proband (VI:4)

Case#: Deceased child, female; age 5.5 months

DiseaseAssertion: Hypertrophic cardiomyopathy with endomyocardial fibroelastosis

FamilyInfo: The mother carried c.2373dup, and the father carried c.592G>T.

ParentalTesting: The mother carried c.2373dup, and the father carried c.592G>T.

CasePresentingHPOs: HP:0001706 HP:0200128 HP:0012664 HP:0002094 HP:0000961

CaseHPOFreeText: Acute heart failure; massive biventricular cardiac enlargement; biventricular dysfunction; progressive dyspnea; blue lips; pale appearance; endocardial fibrosis; cardiopulmonary arrest.

CaseNotHPOFreeText: No congenital heart disease or valve abnormalities were found at autopsy

Genotyping Method: Postmortem molecular testing

Variant: MYBPC3 c.592G>T (p.Asp198Tyr); missense

MYBPC3 c.2373dup, p.Trp792Valfs*41); frameshift duplication

ClinVar: c.592G>T: NR; c.2373dup: 42619

CAID: c.592G>T: NR; c.2373dup: CA012139

gnomAD: c.592G>T was not observed in more than 123,000 individuals; c.2373dup: 0.0017% overall

AdditionalInfo: The child died from severe early-onset cardiac disease at 5.5 months. Autopsy showed endomyocardial fibroelastosis and severe biventricular involvement.

PMID: 35029218

Gene: TPM1

HGNC ID: 12010

Case#: Proband(II-1)

DiseaseAssertion: DCM1Y

FamilyInfo: Chinese Han family with DCM phenotypes.

ParentalTesting: not reported

CasePresentingHPOs: HP:0001644

CaseHPOFreeText: Proband diagnosed with dilated cardiomyopathy and found to carry a TPM1 variant.

CaseNotHPOs: not reported

CaseNotHPOFreeText: not reported

CasePreviousTesting: not reported

Genotyping Method: Next-generation sequencing (NGS), confirmed by Sanger sequencing

FunctionalAnalysis: none reported

Variant: TPM1 c.340G>C (p.E114Q) missense variant

ClinVar: not found

CAID: CA392721071

gnomAD:

AdditionalInfo:

Case1: 14 month, female

DiseaseAssertion: dilated cardiomyopathy

FamilyInfo:The three siblings' cases were born to consanguineous parents. They had DCM and died from decompensated heart failure around the age of 12 months

ParentalTesting: Sanger Sequencing determined the parents carried the variant at the heterozygous state (Figure 1)

CasePresentingHPOs: HP:0002094, HP:0002099, HP:0002098, HP:0002090,

CaseHPOFreeText:productive cough, and whining, wheezing, mitral and tricuspid regurgitation

CaseNotHPOs: NR

CaseNotHPOFreeText:no sign of ischemia,

CasePreviousTesting: cardiac ultrasound

Genotyping Method: sanger sequencing

FunctionalAnalysis: NR

Variant: TNNI3 (NM_000363.5): c.204delG;p.(Arg69AlafsTer8)

ClinVar: 179447

gnomAD: not found

Case#: Family B, Case IV.2; 8-year-old male; diagnosed at age 6

DiseaseAssertion: Dilated cardiomyopathy (DCM)

FamilyInfo: Positive family history of sudden cardiac death (SCD). The proband's brother (IV.1) died at age 2 of SCD and renal failure. Both parents (III.1 and III.2) were asymptomatic heterozygous carriers of MYL3 c.106G>T. Two unaffected siblings were tested: IV.3 was wild-type and IV.4 was heterozygous (Fig. 1b; Supplementary Fig. S2b).

ParentalTesting: Both parents (III.1 and III.2) were confirmed heterozygous carriers of MYL3 c.106G>T by PCR and bidirectional Sanger sequencing, supporting autosomal recessive inheritance (Supplementary Genetic Findings; Fig. S2b).

CasePresentingHPOs: HP:0001644 (Dilated cardiomyopathy); HP:0000085 (Horseshoe kidney); HP:0005162 (Reduced left ventricular ejection fraction).

CaseHPOFreeText: DCM diagnosed at age 6; heart transplantation performed shortly after diagnosis. Clinical evaluation revealed horseshoe kidney, severe left ventricular dysfunction (LVEF 15–20%), moderate right ventricular dysfunction (TAPSE 9 mm), chamber cardiomegaly on coronary CT angiography, and rapid ventricular tachycardia on ECG (Main text, Family B; Supplementary Results, p. 6).

CaseNotHPOs: NR

CaseNotHPOFreeText: NR

CasePreviousTesting: NR (no prior diagnostic genetic testing reported before the study's exome sequencing)

Genotyping Method: Exome sequencing identified the homozygous MYL3 c.106G>T (p.Glu36Ter) variant in the proband (IV.2). PCR and bidirectional Sanger sequencing validated the variant and confirmed segregation in the parents and two unaffected siblings (Supplementary Methods; Supplementary Genetic Findings; Fig. S2b).

FunctionalAnalysis: Zebrafish cmlc1 knockdown and rescue experiments were performed using human MYL3 RNA containing c.106G>T (p.Glu36Ter). Unlike wild-type MYL3 RNA, the mutant RNA failed to rescue the cardiac phenotype, with persistent cardiac edema, ventricular dysfunction, and atrial dilation (Fig. 2; Supplementary Methods; Supplementary Movie S7).

Variant: MYL3 NM_000258.2:c.106G>T (p. Glu36Ter); homozygous nonsense variant

ClinVar: NR

CAID: CA352499542

gnomAD: NR

AdditionalInfo: The authors classified the homozygous MYL3 c.106G>T (p.Glu36Ter) nonsense variant as pathogenic. The variant introduces a premature termination codon at amino acid 36. The proband was born to asymptomatic, consanguineous (first-cousin) parents of Bakhtiyari ancestry. Family segregation and zebrafish functional studies provide supporting evidence (Supplementary Results; Supplementary Genetic Findings; Supplementary Table S2).

Case#: Family C, Case VI.1; female; diagnosed at age 2.5 years; died at age 8

DiseaseAssertion: Unclassified cardiomyopathy

FamilyInfo: Family C has a positive family history of childhood-onset cardiomyopathy and sudden cardiac death. The affected individual (VI.1) was diagnosed with cardiomyopathy at age 2.5 years and died at age 8. Three maternal relatives (V.5, V.6, and V.8) are depicted as affected and deceased in the pedigree (Fig. 1C). Both parents (V.1 and V.2) were clinically unaffected heterozygous carriers of the MYL3 c.482-1G>A splice-acceptor variant. The genotype of VI.1 could not be confirmed because DNA was unavailable.

ParentalTesting: PCR and bidirectional Sanger sequencing confirmed that both parents (V.1 and V.2) were heterozygous carriers of MYL3 c.482-1G>A. Direct testing of the affected daughter (VI.1) was not possible because DNA was unavailable. Her homozygous genotype was therefore suspected but not confirmed (Fig. 1C; Supplementary Genetic Findings).

CasePresentingHPOs: HP:0001638 (Cardiomyopathy); HP:0001645 (Sudden cardiac death).

CaseHPOFreeText: Female diagnosed with unclassified cardiomyopathy at age 2.5 years; died of sudden cardiac death at age 8 (Family C, Fig. 1C).

CaseNotHPOs: NR (no patient-specific negative HPO findings confirmed for VI.1).

CaseNotHPOFreeText: The authors reported no evidence of muscle weakness by neurological examination or history among affected individuals from the three families; however, it is unclear whether this assessment specifically included VI.1.

CasePreviousTesting: NR (no prior genetic testing reported for VI.1).

Genotyping Method: Genetic analysis of the affected individual's mother (V.2) identified MYL3 c.482-1G>A. PCR and bidirectional Sanger sequencing validated the variant and confirmed both parents (V.1 and V.2) as heterozygous carriers. VI.1 was not directly genotyped because DNA was unavailable (Supplementary Genetic Findings; Fig. 1C and S2C).

FunctionalAnalysis: A minigene splicing assay in human HEK293FT cells demonstrated that MYL3 c.482-1G>A causes abnormal RNA splicing. The predominant outcome (~75%) was skipping of the 78-bp exon 5, producing an in-frame deletion (p.Gly161_Glu186del). A less frequent outcome (~25%) was deletion of the first nucleotide of exon 5, causing a frameshift (p.Gly161Valfs*4). Both outcomes are predicted to disrupt EF-hand domains. The authors note that the minigene assay may not fully reflect in vivo splicing frequencies (Supplementary Results, pp. 7–8; Fig. 2E–I).

Variant: MYL3 c.482-1G>A (rs727503300)

ClinVar: 164486

CAID: CA013932

gnomAD: NR MYL3 c.482-1G>A was not found in the gnomAD v4 (GRCh38) region results at chr3:46,860,813. Allele frequency not reported for this variant in the searched dataset.

AdditionalInfo: The affected individual (VI.1) died at age 8, and DNA was unavailable for direct genetic testing. Both clinically unaffected parents (V.1 and V.2) were confirmed heterozygous carriers of MYL3 c.482-1G>A, suggesting that VI.1 may have inherited the variant from both parents; however, her genotype remains unconfirmed. A minigene assay demonstrated that the variant disrupts RNA splicing, predominantly causing exon 5 skipping, with a less frequent frameshift-producing splicing event. These functional findings support a damaging effect of the variant but do not establish VI.1's genotype (Fig. 1C; Fig. 2E–I; Supplementary Genetic Findings and Minigene Assay Results).

Case#: Family A, Case III.7; 38-year-old female; diagnosed at age 26

DiseaseAssertion: Hypertrophic cardiomyopathy (HCM)

FamilyInfo: Positive family history of HCM and SCD. Mother (II.4), brother (III.8), uncle (II.7), and cousin (III.11) died of SCD at ages 55, 26, 57, and 24, respectively. The proband's three children (IV.3, IV.4, IV.5) were homozygous for the MYL3 variant but had normal echocardiograms at ages 18, 13, and 6.

ParentalTesting: Supplementary Table S2 reports parental testing supportive of PM3 (variants in trans). However, DNA was unavailable for the proband's deceased mother (II.4), and individual parental genotypes were not specified in the supplementary genetic findings.

CasePresentingHPOs: HP:0001639 (Hypertrophic cardiomyopathy); HP:0002094 (Dyspnea); HP:0001653 (Mitral regurgitation); HP:0001712 (Left ventricular hypertrophy)

CaseHPOFreeText: HCM diagnosed at age 26 following dyspnea. At age 38, echocardiography showed reverse-curvature HCM with asymmetric left ventricular hypertrophy involving anterior, anterolateral, and lateral segments; maximum wall thickness 22 mm; severe mitral regurgitation; LVEF 55%; E/e' ratio 16.4; resting LVOT gradient 9 and post-maneuver gradient 30. Holter monitoring showed no arrhythmias (Supplementary Results, pp. 5–6; Table S1; Fig. S1).

CaseNotHPOs: HP:0001324 (Muscle weakness)

CaseNotHPOFreeText: Neurological evaluation revealed normal muscle tone, strength 5/5 in upper and lower limbs, no distal or proximal muscle atrophy or fasciculations, and normal creatine phosphokinase levels.

CasePreviousTesting: Exome sequencing was performed; no rare, likely pathogenic variants in other cardiomyopathy-associated genes identified after filtering.

Genotyping Method: Exome sequencing identified the MYL3 variant; bidirectional Sanger sequencing validated the variant. Familial genotyping supported recessive inheritance (Fig. 1a).

FunctionalAnalysis: Zebrafish cmlc1 knockdown and rescue experiments were performed using human MYL3 RNA carrying c.170C>A (p.Ala57Asp). Mutant RNA showed partial phenotypic rescue but no statistically significant improvement in ventricular contractility compared with knockdown alone (Fig. 2a-d).

Variant: MYL3 NM_000258.2:c.170C>A (p.Ala57Asp); homozygous missense variant; rs139794067

ClinVar: 43121

CAID: CA013575

gnomAD: Allele frequency 0.000163 (0 homozygotes), as reported in Supplementary Table S2.

AdditionalInfo: Family A, Case III.7. Clinical characteristics and genetic findings described in the Results section (Fig. 1a and 1d-e). Functional experiments described in Fig. 2. The authors classified c.170C>A as a variant of uncertain significance (VUS).

PMID: 33288880

Gene: MYL3

HGNC ID: 7584

Case#: Female, Hispanic, 4

DiseaseAssertion:Dilated cardiomyopathy

FamilyInfo: Uncle who died at a young age of sudden cardiac death.

ParentalTesting:

CasePresentingHPOs: HP:0001638

"severe decompensated cardiomyopathy at age 4."

CaseHPOFreeText: NR

CaseNotHPOs: NR

CaseNotHPOFreeText:NR

CasePreviousTesting: NR

Genotyping Method: commercial genetic testing and Sanger sequencing

FunctionalAnalysis:

Variant: NM_001276345.2:c.*187C>T

ClinVar: NR

CAID:CA2649785730

gnomAD:NR

AdditionalInfo:

PMID: 26498512

Gene: TNNT2

HGNC ID: 11949

Case#: IV-2; female; age 51; Chinese family

DiseaseAssertion: Hypertrophic cardiomyopathy

FamilyInfo: IV-2 is the mother of V-1

CasePresentingHPOs: HP:0001712 HP:0005144

CaseHPOFreeText: Atypical hypertrophy with a septal thickness of 23 mm; exertional angina for 10 years.

Genotyping Method: Sanger sequencing and targeted next-generation sequencing

Variant: c.3624delC, frameshift

ClinVar: 42727

CAID: CA014493

AdditionalInfo: Also carried CACNB2 p.Ser533Leu and DSP p.Arg1308Gln.

Case#: V-1; male; age 28; Chinese family

DiseaseAssertion: Hypertrophic cardiomyopathy

FamilyInfo: V-1 is part of a large consanguineous HCM pedigree. Family segregation information was reported for the MYBPC3 variant. V-1 died suddenly at age 29

CasePresentingHPOs: HP:0001712 HP:0005144 HP:0032092

CaseHPOFreeText: Left ventricular hypertrophy; increased interventricular septal thickness; left ventricular outflow tract obstruction

Genotyping Method: Sanger sequencing and next-generation sequencing

Variant: c.3624delC, missense

ClinVar: 42727

CAID: CA014493

Case#: IV-6; female; age 64; Chinese family

DiseaseAssertion: Hypertrophic cardiomyopathy

FamilyInfo: IV-6 is a member of the MYBPC3-positive HCM pedigree

CasePresentingHPOs: HP:0001712 HP:0005144

CaseHPOFreeText: Moderately affected, asymmetrical hypertrophy with a maximum wall thickness of 15 mm; normal left ventricular dimensions and systolic function.

CaseNotHPOFreeText: No cardiac symptoms or cardiac events were reported.

Genotyping Method: Sanger sequencing and targeted next-generation sequencing

Variant: c.3624delC, frameshift

ClinVar: 42727

CAID: CA014493

AdditionalInfo: No additional CACNB2 variant was reported.

Case#: Family #6; 36-year-old male

DiseaseAssertion: Arrhythmogenic right ventricular cardiomyopathy (ARVC); diagnosed according to the 2010 revised Task Force Criteria

FamilyInfo: Family #6. No informative segregation evidence specifically linking the MYL3 variant to ARVC was reported. The authors noted that family screening was incomplete or normal in other families, but did not specify which circumstance applied to Family #6.

ParentalTesting: NR

CasePresentingHPOs: HP:0006682 (PVCs)

CaseHPOFreeText: Symptomatic presentation; major right ventricular structural abnormality; minor ECG repolarization criterion; 1,181 ventricular ectopic beats on Holter monitoring; sustained ventricular arrhythmia (specific rhythm not reported).

CaseNotHPOs: HP:0001279 (Syncope); HP:0005162 (Abnormal left ventricular function)

CaseNotHPOFreeText: No cardiac syncope or left ventricular dysfunction reported. Absence of cardiac syncope does not necessarily exclude every form of syncope.

CasePreviousTesting: No pathogenic or likely pathogenic variants identified in established ARVC-associated genes (PKP2, DSG2, DSP, DSC2, JUP, TMEM43, PLN, SCN5A). Subsequent screening included nine sarcomere genes: ACTC1, MYBPC3, MYH7, MYL2, MYL3, TNNC1, TNNI3, TNNT2, and TPM1. The study used broad genetic testing, including whole-exome sequencing in a subset of probands; whether Family #6 underwent whole-exome sequencing was not specified.

Genotyping Method: Sarcomere-gene sequencing and deletion/duplication analysis through clinical cardiomyopathy panels, research-based next-generation sequencing panels, or whole-exome sequencing. The exact initial platform for Family #6 was not specified. Identified variants were confirmed by PCR amplification and Sanger sequencing.

FunctionalAnalysis: NR

Variant: MYL3 NM_000258.2:c.461G>A (p.Arg154His); missense variant; exon 4

ClinVar: 14062

CAID: CA013861

gnomAD: MYL3 c.461G>A (p.Arg154His), GRCh38: 3-46859495-C-T. gnomAD v4: Exome AF = 0.00003557; Genome AF = 0.00001971; Total AF = 0.00003408. European (non-Finnish): AC = 52, AF = 0.00004407. https://gnomad.broadinstitute.org/variant/3-46859495-C-T?dataset=gnomad_r4

AdditionalInfo: Murray et al. (2018), Tables 1 and 2, Family #6. The MYL3 variant was classified as likely pathogenic (LP) according to ACMG criteria, with a PolyPhen-2 score of 0.861. The proband met criteria for definite ARVC, with no reported left ventricular dysfunction. Although the variant was rare and computationally predicted to be damaging, the authors emphasized that evidence demonstrating a causal relationship between sarcomere variants and ARVC remained insufficient. No direct functional analysis of this variant was performed in the study.

PMID: 29709087

Gene: MYL3

HGNC ID: 7584

PMID: 28538763

Gene: TNNT2

HGNC ID: 11949

Case#: Male, 17

DiseaseAssertion: hypertrophic cardiomyopathy

FamilyInfo: All family members were asymptomatic, with normal TTE and ECG, with no evidence of VH.

ParentalTesting:

CasePresentingHPOs: HP:0001639, HP:0001279, HP:0001670, HP:0032092, HP:0031295

CaseHPOFreeText: diastolic type II dysfunction,

CaseNotHPOs: NR

CaseNotHPOFreeText: NR

CasePreviousTesting: genetic analysis of the proband was performed through direct sequencing of the three sarcomere genes: MYH7, MYBPC3 and TNNT2

Genotyping Method: Sanger Sequencing

FunctionalAnalysis: NR

Variant: NR

ClinVar:NR

CAID: NR

gnomAD: NR

AdditionalInfo: underwent clinical and cardiovascular examination, including a 12-lead electrocardiogram (ECG), transthoracic echocardiography (TTE) and 24-hour Holter monitoring. TNNT2 sequenced, but not reported.

Case#: 11 year old girl

DiseaseAssertion: hypertrophic cardiomyopathy

FamilyInfo: unremarkable

ParentalTesting: Both parents were tested and neither carried the variant

CasePresentingHPOs: HP:0001639 HP:0011675

CaseHPOFreeText: Post-mortem examination revealed asymmetric non-obstructive hypertrophy of the interventricular septum.

CaseNotHPOs: Syncope absent

CaseNotHPOFreeText: No complaints, normal exercise tolerance, no syncope, no medications, and no significant family history.

CasePreviousTesting: Autopsy and sudden cardiac death investigation.

Genotyping Method: Genetic testing performed as part of post-mortem investigation; familial cascade screening.

FunctionalAnalysis:

Variant: TPM1 c.656A>T (p.Asp219Val, p.D219V)

ClinVar: absent

CAID: CA2998480361

gnomAD: absent

AdditionalInfo: Variant classified as likely pathogenic (Class IV) by the authors and determined to be de novo.

PMID: 36613463

Gene: TPM1

HGNC ID: 12010

Case#: Female, 4 months, Swedish

DiseaseAssertion: dilated cardiomyopathy

FamilyInfo: Strong family history of DCM and faily history of SCD due to DCM. Maternal grandfather had enlarged left ventricle.

ParentalTesting:

CasePresentingHPOs: HP:0005162, HP:0031295, HP:0001653,

CaseHPOFreeText: enlarged left ventricle,

CaseNotHPOs:HP:0011947

CaseNotHPOFreeText: circulatory collapse

CasePreviousTesting: NR

Genotyping Method: Sanger sequencing

FunctionalAnalysis: NR

Variant: NM_001276345.2:c.548G>A

ClinVar:43649

CAID: CA004727

gnomAD:NR

AdditionalInfo: During cardiac catheterization, cardiac resuscitation due to circulatory collapse was needed.

PMID: 28669108

Gene: TNNT2

HGNC ID: 11949

Case1:Male, 46 years old

DiseaseAssertion:

FamilyInfo: 3 generations of asymptomatic carriers

ParentalTesting:

CasePresentingHPOs:

CaseHPOFreeText:

CaseNotHPOs:HP:0001712

CaseNotHPOFreeText:Left Ventricular hypertrophy

CasePreviousTesting:

Genotyping Method: Not Stated

FunctionalAnalysis:

Variant: c.170C>A VUS

ClinVar:43121

CAID:CA013575

gnomAD:

AdditionalInfo:

PMID: 29914921

Gene: MYL3

HGNC ID: 7584

PMID: 36555486

Gene: MYBPC3

HGNC ID: HGNC:7551

PMID: 30923642

Gene: TPM1

HGNC ID: 12010

Case#: Patient A

DiseaseAssertion: Dilated Cardiomyopathy (DCM)

FamilyInfo: Large multigenerational family with DCM. Six family members identified. TPM1 and VCL variants are connected to disease.

ParentalTesting: Both parents presented with DCM and TPM1 variant c.97G>A.[p.glu33Lys, p.E33K].

CasePresentingHPOs: HP:0001644 HP:0012664 HP:0001635

CaseHPOFreeText: severe heart failure and required heart transplant. Left ventricular ejection fraction.

CaseNotHPOs:unkown

CaseNotHPOFreeText: unkown

CasePreviousTesting: unkown

Genotyping Method: PCR amplification & Sanger sequencing.

FunctionalAnalysis: functional data support that TPM1 and VCL variants act synergistically to impact cardiomyocyte contractility and sarcomeric organization and suggest that together these variants may perturb sarcomeric–costameric interactions.

Variant: TPM1 c.97G>A (p.Glu33Lys; E33K)

ClinVar: not found

CAID: CA018447

gnomAD: not reported

AdditionalInfo:

PMID: 37122207

Gene: TNNT2

HGNC ID: 11949

Case#: 4 month old boy

DiseaseAssertion: Polymorphic ventricular tachycardia

FamilyInfo: His father carried the RYR2 variant and had ventricular premature beats. His mother carried the SCN10A variant and was asymptomatic.

ParentalTesting: Yes. Familial genetic testing showed the RYR2-A1855D variant was inherited from the father and the SCN10A-Q1362H variant was inherited from the mother.

CasePresentingHPOs: HP:0004756

CaseHPOFreeText: 4-month-old male presenting with polymorphic ventricular tachycardia.

CaseNotHPOs: not reported

CaseNotHPOFreeText: not reported

CasePreviousTesting: Clinical cardiac evaluation followed by genetic testing

Genotyping Method: Genetic testing identified novel heterozygous RYR2-A1855D and SCN10A-Q1362H variants.

FunctionalAnalysis: Functional studies showed abnormal calcium handling, prolonged action potentials, increased susceptibility to early afterdepolarizations, and disrupted Ca2+ homeostasis in cells carrying both variants.

Variant: RYR2 (heterozygous) SCN10A

ClinVar: not found

CAID: not found

gnomAD: not found

AdditionalInfo:

Case1:eight-year-old female

DiseaseAssertion: Restrictive cardiomyopathy (RCM)

FamilyInfo: The patient's parents denied any positive family history of cardiac attacks, cardiovascular issues, hypertension, or coronary artery diseases. There was also no reported history of diabetes or obesity among family members. No inherited diseases, including cardiomyopathies or metabolic disorders, were identified in the family history

ParentalTesting: NR

CasePresentingHPOs:HP:0012378, HP:0001695, HP:0100539, HP:0031352, HP:0034030

CaseHPOFreeText:bilateral pedal edema, shortness of breath after engaging in physical activity, typically lasting for 15 min, enlarged bilateral atrium, segmental thickening of the interventricular septum, segmentally diffuse reduction and lack of coordination in ventricular wall pulse amplitude, mild mitral regurgitation, and diminished left ventricular systolic and diastolic function identified by increased parameters of early diastolic velocity (E wave) and low late filling velocity (A wave) (Figure 1A) abnormal bilateral atrial signals, premature atrial beats, junctional ectopic beats, first-degree atrioventricular block, complete right bundle branch block, prolonged QT interval, and abnormal Q wave (Figure 1B).

CaseNotHPOs: NR

CaseNotHPOFreeText: NR

CasePreviousTesting: echocardiography, genetic screening, imaging assessments, blood gas analysis, blood cell counts, carbon dioxide retention

Genotyping Method: whole-exome sequencing (WES)

FunctionalAnalysis: computational analysis

Variant:TNNI3 c.509G>A p.R170Q

ClinVar:165516

gnomAD: not found