No association between IRS‑1 promoter methylation and type 2 diabetes

As a candidate gene for type 2 diabetes (T2D), insulin receptor substrate-1 (IRS‑1) gene variations were found to be associated with the risk of T2D. The aim of our study was to investigate the contribution of promoter DNA meth- ylation of the IRS‑1 gene to the risk of T2D. Using bisulphite pyrosequencing technology, the DNA methylation levels of 3 CpG dinucleotides within the IRS‑1 gene promoter were measured in 48 T2D patients and 48 age- and gender-matched healthy controls. Our results indicated that there was no significant association between the methylation of the IRS‑1 gene promoter and the risk of T2D (P>0.1). A breakdown analysis by gender revealed that IRS‑1 promoter methylation was not associated with an increased risk of T2D for either gender (P>0.1), although there were significantly lower methy­ lation levels of CpG1 (P=0.002) and CpG2 (P=0.043) within the IRS‑1 gene promoter in males than in females.