[Mutations in genes for sarcomeric proteins]

Idiopathic cardiomyopathy(ICM) is by definition of unknown etiology. There are four clinical types of ICM; hypertrophic cardiomyopathy(HCM) characterized by ventricular hypertrophy associated with reduced compliance of the heart and accompanied by myofibrillar disarray, dilated cardiomyopathy(DCM) characterized by dilated ventricles associated with systolic dysfunction, restricted cardiomyopathy (RCM) and arrhythmogenic right ventricular cardiomyopathy(ARVC). Recent molecular genetic analyses have now revealed disease-associated mutations in ICM, especially in familial HCM and familial DCM. Mutations in 9 different disease genes (MYH7, TNNT2, TPM1, MYBPC3, MYL3, MYL2, TNNI3, CACT and TTN) cause HCM, while mutations in 3 different genes(CACT, DES and DMD) cause DCM in adults. In this review, I will summarize our current data on sarcomere mutations found in Japanese ICM, especially in HCM and DCM.