Genetics of idiopathic dilated cardiomyopathy

Familial dilated cardiomyopathy (DCM) should be an "evidence-based" diagnos is derived from clinical and echocardiographic screening of informed and co nsenting relatives of index patients, and on the examination of clinical re ports for deceased relatives. Most familial dilated cardiomyopathy pedigree s show an autosomal pattern of inheritance. Very few of them are X-linked a nd matrilinear. Autosomal recessive in heritance is difficult to be assesse d in an evidence-based setting. By linkage analysis, several loci, but no d isease gene, have been identified. At present, few cases of familial dilate d cardiomyopathy can benefit of a molecular diagnosis. The diagnosis of dystrophin defect-related dilated cardiomyopathy is import ant for patients and families. especially for carrier detection. These pati ents present X-linked inheritance, dominant cardiac involvement and raised levels of serum creatine phosphokinase. Defects of the glycoprotein complex associated to dystrophin (DAG) are rare skeletal muscle diseases With poss ible cardiac involvement. Mitochondrial diseases, both pure cardiomyopathie s and multiorgan syndromes involving the heart, are associated to defects o f mitochondrial DNA genes or of nuclear genes coding fur mitochondrial prot eins. Barth's syndrome develops in male children with granulocytopenia, dil ated cardiomyopathy, and methylglutaconic aciduria. Cardiomyopathies with a trioventricular block are observed in hemochromatosis. Emery-Dreifuss syndr ome, desmin storage disease, and in isolated familial dilated cardiomyopath y. Actin defects were recently identified in 2 unrelated patients with fami lial dilated cardiomyopathy. Desmin defects were also recently identified i n 1 familial dilated cardiomyopathy. The overall knowledge, although in progression, is still limited. Clinical family screening identifies familial forms, preclinical cases, and inherita nce pattern. By candidate gene screening, the molecular diagnosis can br pr ovided for dystrophin, DAG, mitochondrial DNA, actin and desmin gene defect s.