DNA methylation of in impaired glucose tolerance.

In the present study, the expression levels and DNA methylation status of ()-375 in patients with impaired glucose tolerance (IGT) and type 2 diabetes mellitus (T2DM) were analyzed and the role of DNA methylation of in the pathogenesis of T2DM was investigated. Compared with the levels in patients with normal glucose tolerance (NGT; n=53), the samples from patients with IGT (n=44) exhibited downregulation of , while those from patients with T2DM (n=54) exhibited upregulation of in the plasma. Additionally, the samples from patients with IGT were observed to be hypermethylated compared with those from patients with T2DM and NGT (P=0.042). Analysis of three CpG units (CpG1.2, CpG20 and CpG25.26.27) from 17 CpG sites (between -990 and -1,258 bp, relative to the transcription start site) revealed higher methylation levels in patients with IGT compared with those in patients with NGT (P<0.05). The methylation of two CpG units (CpG1.2 and CpG25.26.27) was higher in patients with IGT than in the patients with T2DM (P<0.05). Thus, the present study demonstrated that the promoter was hypermethylated and the levels of in the plasma were downregulated in the patients with IGT. DNA hypomethylation may have an important role in the regulation of expression and may contribute to the pathogenesis of T2DM.