Familial Dilated Cardiomyopathy

Anant Khositseth, MD; Virginia V. Michels, MD


Cardiovasc Rev Rep. 2004;25(5) 

In This Article

Abstract and Introduction

Dilated cardiomyopathy (DCM) is a heterogeneous disorder that is familial in approximately 30% of cases. Although several genes have been identified that can cause familial DCM, molecular analyses for these genes are generally not available for clinical analysis.Therefore, most cases of DCM are of unknown etiology, and until a second member of a family is diagnosed, the disease may appear to be sporadic. Early diagnosis and treatment of DCM is important.This review summarizes the known genetic causes of DCM. Published data on development of DCM amongst first-degree relatives of patients with DCM, as well as the course of familial compared with apparently nonfamilial DCM, are also reviewed.

Dilated cardiomyopathy (DCM) is characterized by dilation and impaired contraction of one or both ventricles.[1] Patients usually present with congestive heart failure that often is progressive. Arrhythmias, thromboembolism, and sudden death are common. DCM may be idiopathic or secondary to ischemia, viral infections, immunologic factors, or toxins (such as alcohol). Idiopathic DCM is a heterogeneous heart muscle disease that affects approximately 1 in 2500 persons;[2] however, the prevalence of DCM may be even higher because of incomplete ascertainment of asymptomatic patients. In many cases, it is familial. The histologic appearance of the myocardium in DCM is nonspecific.

Familial DCM is defined as DCM in two or more first- or second-degree relatives. Without careful screening of relatives, it has been documented that familial DCM can be missed in up to 18% of cases.[3] Asymptomatic relatives may have undiagnosed DCM, and relatives reported to have DCM may actually have other forms of cardiomyopathy such as ischemic cardiomyopathy. Classification into familial and nonfamilial cases therefore requires echocardiographic investigation of relatives. Consequently, few studies on outcomes in familial and nonfamilial DCM have been reported until recently, and these data are reviewed here. Molecular causes of familial DCM have been identified in the research setting, but the genetic etiology for most cases remains unknown.

We reviewed the frequency of familial DCM, the molecular genetic basis of familial DCM, the development of DCM among relatives of patients with DCM, and the recommendations for screening and monitoring of relatives of probands with DCM.


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