Echocardiographic characterization of hypertrophic cardiomyopathy in Chinese patients with myosin-binding protein C3 mutations.

Hypertrophic cardiomyopathy (HCM) is a common autosomal dominant cardiac disease, affecting 1 in 500 people. Myosin-binding protein C3 () gene mutations are the most common genetic cause of HCM. However, the prevalence of the gene mutation in Chinese patients with HCM, and their echocardiographic characteristics, remain unknown. In the present study, 48 Chinese patients with HCM were sequenced to identify the gene and were characterized by their clinical features using 2-dimensional echocardiography and real-time 3-dimensional echocardiography. Nine mutations were identified in seven unrelated patients out of 48 cases, which accounts for a 15% prevalence of mutations in Chinese patients with HCM. Family members of the seven patients were further tested and divided into the following two groups based on HCM phenotype and mutations: Positive genotype with left ventricular (LV) hypertrophy (LVH) (G+/LVH+, n=18); and positive genotype without LVH (G+/LVH-, n=23). These groups were compared with matched normal control subjects (n=30). G+/LVH+ patients showed significantly lower septal and lateral Tissue Doppler imaging (TDI)-derived systolic, early and late diastolic mitral annular velocities compared with the controls. In addition, diastolic dyssynchrony index (DDI) was markedly higher in the G+/LVH+ subjects. However, only septal Ea was significantly lower in G+/LVH- subjects in comparison with controls, with no significant difference in lateral Sa, Ea and Aa, and DDI. In conclusion, the patients in the present study demonstrated a 15% prevalence of gene mutations in the Chinese HCM population. gene mutations may cause regional LV hypertrophic remodeling first and further proceed to global hypertrophic remodeling and myocardial diastolic dysfunction.