MYH7 and familial long QT syndrome: Furthermore, mutations in a single gene can cause different diseases, e.g. mutations in the myosin heavy chain 7 (MYH7) gene cause hypertrophic cardiomyopathy (HCM), restrictive cardiomyopathy and dilated cardiomyopathy (DCM) [3-5], while mutations in the sodium channel, type V, alpha subunit (SCN5A) gene cause long QT syndrome (LQTS) and Brugada syndrome [6,7].