AN AUTOSOMAL GENOMIC SCAN FOR LOCI LINKED TO TYPE-II DIABETES-MELLITUS AND BODY-MASS INDEX IN PIMA-INDIANS

Genetic factors influence the development of type II diabetes mellitus , but genetic loci for the most common forms of diabetes have not been identified. A genomic scan was conducted to identify loci linked to d iabetes and body-mass index (BMI) in Pima Indians, a Native American p opulation with a high prevalence of type II diabetes. Among 264 nuclea r families containing 966 siblings, 516 autosomal markers with a media n distance between adjacent markers of 6.4 cM were genotyped. Variance -components methods were used to test for linkage with an age-adjusted diabetes score and with BMI. In multipoint analyses, the strongest ev idence for linkage with age-adjusted diabetes (LOD = 1.7) was on chrom osome 11q, in the region that was also linked most strongly with BMI ( LOD = 3.6). Bivariate linkage analyses strongly rejected both the null hypothesis of no linkage with either trait and the null hypothesis of no contribution of the locus to the covariation among the two traits. Sib-pair analyses suggest additional potential diabetes-susceptibilit y loci on chromosomes Iq and 7q.