Association of the M315i variant in the transient receptor potential Vanilloid receptor-1 (TRPV1) gene with type 1 diabetes in an Ashkenazi Jewish population

Background: Type 1 diabetes in humans is an autoimmune disease in which T cells target pancreatic islets of Langerhans, leading to the progressive destruction of the insulinproducing beta cells. Both genetic and environmental factors contribute to the development of autoimmune diabetes. The non-obese diabetic (NOD) mouse model of human type 1 diabetes demonstrates two missense mutations in the transient receptor potential vanilloid receptor-1 (TRPV1) gene. Objectives: To investigate whether polymorphism in the TRPV1 gene may play a role in the predisposition to human type 1 diabetes. Methods: We genotyped 146 Ashkenazi Jewish type 1 diabetic patients and 205 Ashkenazi Jewish healthy controls for the rs222747 (M315I), rs224534 (T469I) and rs8065080 (I585V) variants of the TRPV1 gene. Results: There was a significant increase in the rs222747 (M315I) variant of the TRPV1 gene in the type 1 diabetes cohort compared to the control: rs222747 (M315I) homozygous: (61% vs. 48.3%, P = 0.02). Logistic regression analysis revealed that type 1 diabetes was significantly associated with rs222747 (M315I), such that having diabetes increased the odds of rs222747 homozygosity (M315I) by 67.2%, odds ratio 1.6, 95% confidence interval 1.08-2.57, P < 0.02. No difference was found in the rs224534 (T469I) and rs8065080 (I585V) allelic variants. There was no difference in any of the TRPV1 variants by gender, age when type 1 diabetes was diagnosed, body mass index, glycemic control, blood pressure, positive autoantibodies (ICA, GAD, IAA), and other autoimmune diseases. Conclusions: Our study demonstrates that TRPV1 may be a susceptible gene for type 1 diabetes in an Ashkenazi Jewish population. These results should be replicated in the same ethnic group and in other ethnic groups.