Phenotypic variation among siblings with arrhythmogenic right ventricular cardiomyopathy.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is primarily a familial disease with autosomal dominant inheritance. Incomplete penetrance and variable expression are common, resulting in broad disease spectrum. Three patterns of phenotypic expression have been described: (1) "classic" subtype, with predominant right ventricle involvement, (2) "left dominant" subtype, with early and dominant left ventricle involvement, and (3) "biventricular" subtype, with both ventricles equally affected. Genotypephenotype associations have been described, but there are other genetic and non-genetic factors that can affect disease expression. We describe two different phenotypic expressions of ARVC in a family.