Dilated cardiomyopathy: more genes means more phenotypes

This editorial refers to ‘Mutation screening in dilated cardiomyopathy: prominent role of the beta myosin heavy chain gene’† by E. Villard et al., on page 794 Dilated cardiomyopathy (DCM) is the third most common cause of heart failure after coronary artery disease and hypertension. DCM is the most frequent form of primary myocardial disease. Clinically, DCM is characterized by a progressive course of ventricular dilatation and systolic dysfunction. The different stages of DCM are reflected by the presentation of asymptomatic patients with left ventricular dilatation or impaired systolic function, patients with exercise-induced symptoms of heart failure, or overt congestive heart failure. The life expectancy is limited and varies according to the underlying aetiology.1 Myocarditis, immunological abnormalities, toxic myocardial damage, and genetic factors are all assumed to be causes. The familial occurrence of DCM, mostly as an autosomal dominant trait, is more common than generally believed. As a matter of fact, 20–30% of all cases of DCM are caused by genetic mutations.2