ENPP1/PC-1 K121Q polymorphism and genetic susceptibility to type 2 diabetes.

Genetic susceptibility modulates the impact of obesity on risk for type 2 diabetes. The present study evaluates the role of ENPP1 K121Q polymorphism in prediction of type 2 diabetes in three populations that differ in susceptibility to diabetes and environmental exposure. The three cohorts included 679 nonmigrant South Asians living in Chennai, India (223 with type 2 diabetes); 1,083 migrant South Asians living in Dallas, Texas (121 with type 2 diabetes); and 858 nonmigrant Caucasians living in Dallas, Texas (141 with type 2 diabetes). Patients with type 2 diabetes were included in these cohorts if they had diabetes onset before the age of 60 years. The prevalence of subjects carrying the polymorphic ENPP1 121Q allele was 25% in the nondiabetic group and 34% in the diabetic group of South Asians living in Chennai (P = 0.01). The prevalence in the nondiabetic and diabetic groups were 33 and 45% (P = 0.01) for the South Asians living in Dallas and 26 and 39% (P = 0.003) for the Caucasians. Although further replication studies are necessary to test the validity of the described genotype-phenotype relationship, our study supports the hypothesis that ENPP1 121Q predicts genetic susceptibility to type 2 diabetes in both South Asians and Caucasians.