Common variants of homocysteine metabolism pathway genes and risk of type 2 diabetes and related traits in Indians.

Hyperhomocysteinemia, a risk factor for cardiovascular disorder, obesity, and type 2 diabetes, is prevalent among Indians who are at high risk of these metabolic disorders. We evaluated association of common variants of genes involved in homocysteine metabolism or its levels with type 2 diabetes, obesity, and related traits in North Indians. We genotyped 90 variants in initial phase (2.115 subjects) and replicated top signals in an independent sample set (2.085 subjects). The variant MTHFR-rs1801133 was the top signal for association with type 2 diabetes (OR = 0.78 (95%  CI = 0.67-0.92), P = 0.003) and was also associated with 2 h postload plasma glucose (P = 0.04), high-density lipoprotein cholesterol (P = 0.004), and total cholesterol (P = 0.01) in control subjects. These associations were neither replicated nor significant after meta-analysis. Studies involving a larger study population and different ethnic groups are required before ruling out the role of these important candidate genes in type 2 diabetes, obesity, and related traits.