Aborted sudden cardiac death and a severe form of hypertrophic cardiomyopathy in a 2-year-old.

Although hypertrophic cardiomyopathy has a reported prevalence of 1/500, compound, double, and triple mutations are infrequent. There is phenotypic variation between individuals with HCM, making disease course difficult to predict. There is some debate as to whether multiple mutations confer a worse prognosis and the extent to which the mutations affect an individual's prognosis. We report a case of homozygous MYBPC3 mutations in a 2-year-old presenting with aborted sudden cardiac death and a severe form of hypertrophic cardiomyopathy.