A major advance in the study of the pathogenesis of dilated cardiomyopathy (DC) 
has been the identification of a familial trait in a relevant proportion of 
cases (more than 25%), which indicates that, at least in these cases, a mutated 
gene is the cause of the disease. Familial dilated cardiomyopathy is a 
genetically heterogeneous disorder, most frequently with autosomal-dominant 
inheritance. Five different loci that cosegregate with the disease have been 
mapped so far; the identification of the disease genes is still in progress. The 
only disease gene known so far is the dystrophin gene, which causes X-linked DC. 
By analogy with dystrophin, it is believed that other cytoskeletal proteins 
could be involved in the pathogenesis of DC. Finally, in right ventricular 
cardiomyopathy, a peculiar form of cardiomyopathy that is frequently familial as 
well, several disease loci have been described. Also in this case, no disease 
gene has been yet identified. The advances in clinical and molecular genetics of 
DC have relevant clinical and therapeutic implications.