Case1: 2-year-old female

DiseaseAssertion: restrictive cardiomyopathy, dilated cardiomyopathy

FamilyInfo:The maternal family history was negative for any form of cardiomyopathy or sudden death. Paternal family history was unknown, the mother (1-II:2) and maternal half-brother (1-III:2) were both heterozygous for the TNNI3 p.Arg136∗ variant, mother (1-II:2, age 20) and half-brother (1-III:2, age 21 months) demonstrated normal heart function on echocardiography. ParentalTesting: Clinical exome sequencing done on mother of proband

CasePresentingHPOs: HP:0032025, HP:0002140, HP:0005180, HP:0001653, HP:0005117

CaseHPOFreeText: left-sided facial and extremity weakness, enlarged cardiac silhouette with interstitial opacities, dilated left and right atria, unusual morphology of the chordae tendineae of both atrioventricular valves was noted, leading to a tethering phenomenon

CaseNotHPOs: HP:0001712,

CaseNotHPOFreeText: normal systolic function

CasePreviousTesting: Chest Xray, Echocardiogram, Head CT

Genotyping Method: clinical exome sequencing

FunctionalAnalysis: Immunostaining on heart tissue from patient, Quantitative analysis of heart tissue, Transmission electron microscopy with immersion fixed heart samples

Variant:homozygous TNNI3 nonsense variant, c.406C>T (p.Arg136∗)

ClinVar:488853

CAID:CA407440677

gnomAD:chr19-55154173-G-A v4