Gender differences in the clinical features of hypertrophic cardiomyopathy caused by cardiac myosin-binding protein C gene mutations.

Background: Although gender may be one of the important factors modifying phenotypic expression in hypertrophic cardiomyopathy (HCM), there has been little information on it.

Methods And Results: We investigated gender differences in the clinical features of HCM caused by cardiac myosin-binding protein C gene (MYBPC3) mutations. Sixty-one subjects (28 families) carrying MYBPC3 mutations were studied. Of the 61 subjects with MYBPC3 mutations, 50 patients including 23 female patients were phenotype-positive by echocardiography. Disease penetrance in subjects aged ≤40 years old was 92% in males and 67% in females. Females showed delayed onset of left ventricular hypertrophy compared with males in subjects who were genotype-positive. Female patients were more symptomatic at diagnosis than were males (mean New York Heart Association class: 1.7±0.8 versus 1.2±0.4, p=0.012). From a longitudinal point of view by age, no significant gender difference in cardiovascular deaths or cardiovascular events was found. During the follow-up period after diagnosis of HCM (13±8 years), female patients who were phenotype-positive had significantly more frequent heart failure events than did phenotypically affected male patients (p=0.028).

Conclusions: Although females with MYBPC3 mutations showed later onset of the disease, female patients were more symptomatic at diagnosis and had more frequent heart failure events once they had developed hypertrophy.