MAPPING A CARDIOMYOPATHY LOCUS TO CHROMOSOME 3P22-P25

Dilated cardiomyopathy (DCM) is a common disorder characterized by car diac dilation and reduced systolic function. To identify a cardiomyopa thy gene, we studied a family with DCM associated with sinus node dysf unction, supraventricular tachyarrhythmias, conduction delay, and stro ke. A general linkage approach was used to localize the disease gene i n this family. Linkage to D3S2303 was identified with a two-point lod score of 6.09 at a recombination fraction of 0.00. Haplotype analyses mapped this locus to a 30 cM region of chromosome 3p22-p25, excluding candidate genes encoding a G-protein (GNAI2), calcium channel (CACNL1A 2), sodium channel (SCN5A), and inositol triphosphate receptor (ITPR1) . These data indicate that a gene causing DCM associated with rhythm a nd conduction abnormalities is located on chromosome 3p, and represent the first step toward disease gene identification.