Family association studies of markers on chromosome 2q and Type 1 diabetesin subjects from South India

Background Several Type 1 diabetes susceptibility loci have been located to chromosome 2q12-21. However, results have not always been consistent and t his may reflect study design and the population analysed. We have used a fa mily-based design to look for an association between Type 1 diabetes and ma rkers located to 2q12-21. Methods Ninety-one South Indian families consisting of subjects with Type 1 diabetes and their parents were genotyped for eight polymorphic markers lo calised to 2q12-21, which includes the interleukin-1 gene cluster. Radiatio n hybrid mapping was used to localise the map position of D2S308 and D2S363 on 2q12-21. The extended transmission disequilibrium test was used for sta tistical analysis. Results No associations were found between Type 1 diabetes and markers loca ted in and around the interleukin-1 gene cluster or the interleukin-1 Type 1 receptor. In contrast, a suggestive association was found between Type 1 diabetes and two closely-linked markers telomeric of the interleukin-1 gene cluster (D2S308 and D2S363, separated by 3.3 cR) (p=0.004 and p=0.002, res pectively). Conclusion This preliminary study suggests that a locus close to D2S308 and D2S363 is involved in the aetiology of Type 1 diabetes in the South Indian population. Copyright (C) 2000 John Wiley & Sons, Ltd.