Clinical spectrum in a family with tropomyosin-mediated hypertrophic cardiomyopathy and sudden death in childhood.

This report demonstrates variable clinical courses in several members of a family with tropomyosin-mediated hypertrophic cardiomyopathy (HCM) (L185R mutation). The index case was an 8-year-old girl who died from sudden cardiac death and was diagnosed with HCM on autopsy. Her father had minimal hypertrophy but had an implantable cardioverter defibrillator placed prophylactically with no appropriate shocks. Two brothers progressed from normal phenotype to HCM on follow-up, the younger with significant hypertrophy and the older with mild hypertrophy. They both had malignant arrhythmia courses with VF, which was terminated by ICD shock. In conclusion, family members with same genotype can have significantly variable phenotypes.