proband (IV.3)
Case#: a 2‐year‐old white girl who was found to have RCM following an evaluation precipitated by the sudden death of her older brother.
DiseaseAssertion: Restrictive cardiomyopathy
FamilyInfo: 4‐year‐old brother presented with a sudden cardiac arrest while running on a soccer field and could not be resuscitated. Her father had restrictive physiology and arrhythmias. The TNNT2 variant was found in the father and two children
ParentalTesting: Father carried the variant. For both paternal grandparents tested negative and the proband inherited the variant from her father.
CasePresentingHPOs: HP:0001723, HP:0001639, HP:0031295, HP:0030718, HP:0001695
CaseHPOFreeText: "Her ECG demonstrated criteria for right and left atrial enlargement with marked repolarization abnormality. Echocardiogram revealed mild right atrial and severe left atrial enlargement (left atrial volume, 61.5 cc/m2; normal, 16–28), with mildly increased left ventricular mass and otherwise normal ventricular dimensions. Right and left ventricular systolic function was preserved. "
CaseNotHPOs: not reported
CaseNotHPOFreeText: Ventricular dimensions and biventricular systolic function were reported as normal.
CasePreviousTesting: Cardiomyopathy‐based panel testing (Familion; Transgenomic, Inc., New Haven, CT) was conducted on the proband, demonstrating a single, heterozygous, variant TNNT2‐R94C (c.280C>T).
Genotyping Method: Clinical genetic testing was performed on family members using the same HCM panel test.
FunctionalAnalysis: Biophysical experiments using recombinant human TNNT2‐R94C demonstrated impaired cardiac regulation at the molecular level attributed to reduced calcium‐dependent blocking of myosin's interaction with the thin filament.
Variant: c.835C>T, p.Gln279Ter
ClinVar: 165549
CAID: CA004288
gnomAD: not reported
AdditionalInfo: not reported