A genome-wide search for Type II diabetes susceptibility genes in Chinese Hans

Aims/hypothesis. The aim of the study was to search for Type II (non-insulin-dependent) diabetes mellitus susceptibility genes in a Chinese population. Methods. A genome-wide scan was carried out using non-parametric linkage analyses. We studied 102 families (478 family members) who were Chinese Hans residing in east and south-east China, including 282 diabetic patients, among them 142 independent affected sibpairs were available for genotyping. A total of 247 fluorescence labelled microsatellite markers, with an average resolution of 15 cM, were amplified. GENEHUNTER was used for the non-parametric linkage analyses. Results. Two loci on chromosome 9 D9S171 and D9S175 showed suggestive evidence for linkage, with an NPL-score of 3.286 and 2.939 respectively, and ap value of 1.19 . 10(-4) and 4.47 . 10-4. A locus on the long arm of chromosome 20, D20S196 showed a rise in the non-parametric-linkage score (from 1.517 to 2.922) and a corresponding decrease in the p value from 0.04 to 6.5 . 10(-4) when families with lower BMI were analysed alone. Other loci with weaker evidence for linkage were also observed. Conclusions. Our results suggest that chromosome 9 contains genes involved in the susceptibility to Type II diabetes in an eastern and southeastern Chinese Han population, and chromosome 20 could hide genes linked to Type II diabetes in families with a lower BMI. Other regions could also hide susceptibility genes with minor effects.