Confirmation of three susceptibility genes to insulin-dependent diabetes mellitus: IDDM4, IDDM5 and IDDM8

Previous genome-wide mapping studies have provided suggestive linkage evidence for several novel susceptibility loci responsible for insulin-dependent diabetes mellitus (IDDM); however, the evidence was not sufficient to confirm the existence of these genes. We analyzed 265 Caucasian families with IDDM and report the first evidence that meets the standard for confirmed linkage for three susceptibility loci. The maximum LOD scores (MLS) were 3.9, 4.5 and 3.6 in our data set, and 5.0, 4.6 and 5.0 for our data combined with non-overlapping data from the literature, for IDDM4 on chromosome 11q13, IDDM5 on 6q25, and IDDM8 on 6q27, respectively. However, we could not confirm linkage for IDDM3 on 15q26 and IDDM7 on 2q31-q33, or linkage disequilibrium between D2S152 and IDDM7.