GENETIC-HETEROGENEITY IN FAMILIAL DILATED CARDIOMYOPATHY

Familial dilated cardiomyopathy (FDCM), an inherited primary form of m yocardial disease, is a significant cause of morbidity and mortality a t all ages and the leading reason for cardiac transplantation worldwid e. Although typically inherited as an autosomal dominant disorder, all forms of inheritance have been recognized. FDCM appears to be respons ible for approximately 20-30% of all cases of dilated cardiomyopathy, the most common form of cardiomyopathy. Recently, two families having autosomal dominant FDCM were mapped. The first family had conduction a bnormalities and FDCM and was mapped to 1p1-1q1, while the second fami ly, which had pure FDCM, was mapped to 9q13-q22. Neither gene has been identified to date. In this report, one family with pure FDCM was ana lyzed for linkage to the 1p1-1q1 and 9q13-q22 loci using parameteric l inkage analysis, with linkage to both regions excluded. This demonstra tes that the pure form of FDCM is caused by multiple different genes, i.e., genetic heterogeneity. Identification of large families with FDC M will be required to identify the various genes responsible for this important clinical entity. (C) 1995 Academic Press, Inc.