Guidelines for the diagnosis and management of familial dilated cardiomyopathy.

Dilated cardiomyopathy (DCM) is a myocardial disorder that is a major cause of heart failure and death. Recent data indicate that genetic factors are important in the pathogenesis of DCM and may account for at least one-third of cases of "idiopathic" DCM. Apart from a positive family history, there are no specific clinical manifestations that reliably distinguish familial from non-familial DCM, and phenotypic features may vary between families and within members of a single family. Clinical screening with ECG and echocardiography of all first-degree relatives of index cases with "idiopathic" DCM is strongly recommended to identify familial disease and to determine the number of affected individuals within families. Molecular genetics studies have shown that familial DCM is a genetically-heterogeneous disorder with nearly 40 chromosomal loci and disease genes identified to date. Mutations in the known disease genes occur relatively infrequently however. Although commercial genetic testing for selected disease genes is available, the cost and low yield have limited its widespread use. The development of next-generation sequencing technologies promises to expedite the discovery of new DCM disease genes and help to take genetic testing from the research laboratory into routine clinical practice. Affected individuals should receive standard pharmacological therapy according to the severity of symptoms and signs of heart failure. Asymptomatic family members should undergo periodic echocardiographic screening to detect early signs of disease. The optimal management of asymptomatic individuals with suspected early disease is not yet established.