ABSENCE OF LINKAGE BETWEEN IDIOPATHIC DILATED CARDIOMYOPATHY AND CANDIDATE GENES INVOLVED IN THE IMMUNE FUNCTION IN A LARGE ITALIAN PEDIGREE

Idiopathic dilated cardiomyopathy (IDC) is a heart disease of unknown aetiology characterised by impaired ventricular function usually assoc iated with dilatation of the cardiac chambers. In order to test the hy pothesis of an immunological cause for the disease at the genetic leve l, we performed linkage analysis between the putative disease locus an d some of the potential candidate genes involved in the immune respons e or coding for the targets for autoantibodies in a large multigenerat ion family (63 members) from southern Italy with autosomal dominant tr ansmission of the disease. Twenty-nine polymorphic markers on 18 diffe rent chromosomal locations were investigated, including markers linked to the genes coding for the HLA antigens, the immunoglobulin heavy an d light chains, the receptors for the immunoglobulin Fc fragments, the subunits of the T cell receptor and the associated CD3, CD4, CD8, and CD45 antigens, interleukins 1, 3, 4, 5, 6, 9, and 11, the interleukin 1 and 2 receptors, and the genes coding for the beta(1) adrenorecepto r, the adenine nucleotide translocator-1, and the cardiac alpha and be ta myosin heavy chains. No evidence for genetic linkage to IDC was fou nd at any of these candidate loci. These results indicate that the sti ll unidentified IDC gene maps outside several loci involved in the reg ulation of immune reactivity.