Pleiotropy of Type 2 Diabetes with Obesity

The risk of type 2 diabetes (T2D) increases with obesity. One possible explanation is that pleiotropic genes affect risk of both T2D and obesity. To identify pleiotropic genes, we performed bivariate analysis of T2D with waist-hip ratio (WHR) and with body mass index (BMI) in the African American subset of the Genetics of NIDDM (GENNID) sample. Of 12 T2D loci identified through suggestive or higher univariate lod scores, we inferred pleiotropy with obesity for six (chromosomes 1 at 17–19 MB, 2 at 237–240 MB, 7 at 54–73 MB, 13 at 26–30 MB, 16 at 26–47 MB, and 20 at 56–59 MB). These findings provide evidence that at least some of the co-occurrence of obesity with T2D is due to pleiotropic genes. We also inferred four obesity loci through suggestive or higher lod scores for WHR (chromosomes 1 at 24–32 MB, 2 at 79–88 MB, 2 at 234–238 MB, and 3 at 148–159 MB).