GENETIC-MAPPING OF A SUSCEPTIBILITY LOCUS FOR INSULIN-DEPENDENT DIABETES-MELLITUS ON CHROMOSOME 11Q

LOCI in the major histocompatibility complex (MHC) on chromosome 6 and the insulin (INS) region on chromosome 11 have been implicated in sus ceptibility to insulin-dependent diabetes mellitus (IDDM) through cand idate gene investigations(1-5), but they may account for less than 50% of genetic risk for the disease(6). Genome-wide linkage studies have led to localization of more than 10 susceptibility loci for insulin-de pendent diabetes in the non-obese diabetic (NOD) mouse(7) and the BB r at(8). Similar studies are now possible in humans through the developm ent of dense genetic maps of highly informative microsatellite loci ob tained using polymerase chain reaction analysis(9). We have applied mi crosatellite markers from recent Genethon maps(10,11), and other highl y informative markers, in a genome-wide linkage study in IDDM. Here we report evidence for the localization of a previously undetected susce ptibility locus for IDDM in the region of the FGF3 gene on chromosome 11q. Our result shows the potential of genome-wide linkage studies to detect susceptibility loci in IDDM and other multifactorial disorders.