[Genetic heterogeneity of myosin heavy chain 7 gene G823E mutation in familial hypertrophic cardiomyopathy in Chinese].

OBJECTIVE: To study the disease-causing gene mutations in familial hypertrophic cardiomyopathy (HCM) in Chinese and to reveal the relationship between the genotype and the phenotype.

METHODS: Peripheral blood samples were collected from 12 members of a HCM family, and 120 healthy volunteers in China. PCR and double deoxygenation chain termination method were used to analyze the cardiac troponin T gene (TNNT2), beta-myosin heavy chain gene (MYH7) gene and myosin binding protein C gene (MYBPC3) and to detect mutations.

RESULTS: Mutation G14452A was identified in exon 22 of MYH7 gene in 4 family members, causing the conversion of glycine (G) into glutamic acid (E). The onset ages and clinical manifestations of the family members carrying the mutation G823E, including 2 patients (the proband, male, with the onset age of 51, and his 26-year-old second son with the onset age of 20), and 2 carriers (his 31-year-old elder son and 29-year-old elder daughter), presented significant individual differences.

CONCLUSIONS: The G823E mutation of MYH7 gene is the causal mutation of familial HCM. The heterogeneity of phenotypes suggests that multiple factors may be involved in the pathogenesis of HCM.