Genetic analysis of chromosome 2 in Type 1 diabetes. Analysis of putative loci IDDM7, IDDM12, and IDDM13 and candidate genes NRAMP1 and IA-2 and the interleukin-1 gene cluster

In the spontaneous mouse model of type 1 diabetes, the nonobese (NOD) strain, a type 1 diabetes locus, Idd5 , has been mapped to chromosome 1. Because mouse chromosome 1 shares a homologous 33-cM region between the genes col3a1 and col6a3 with human chromosome 2q31–q35 (data shown at http://www.ncbi.nlm.nih.gov/Omim/Homology/), several groups have searched chromosome 2 for loci affecting human type 1 diabetes. Previous studies have provided evidence for at least three type 1 diabetes loci ( IDDM7 , IDDM12 , and IDDM13 ) within a 23-cM region of chromosome 2q31–q35. We have now evaluated linkage on chromosome 2, by multipoint analysis using Mapmaker/Sibs, of 34 microsatellite markers and an interleukin-1 (IL-1) Taq I polymorphism in 352 U.K. families.