AluYb8 insertion in the MUTYH gene is related to increased 8-OHdG in genomic DNA and could be a risk factor for type 2 diabetes in a Chinese population

The Mutyh DNA glycosylase is involved in the repair of oxidized DNA bases. Because oxidative stress may contribute to increased diabetes risk, the common variant of the MUTYH gene (AluYb8MUTYH) was investigated for its possible role in type 2 diabetes mellitus (T2DM). A total of 565 T2DM patients and 565 healthy subjects from China were enrolled in a case-control study. The distribution of AluYb8MUTYH differed in diabetic patients from controls, with a moderately increased percentage of the mutant allele (P) (44.7% versus 40.3%, P = 0.033, OR = 1.199). However, this distribution was similar between the diabetic early-onset and late-onset subgroups. Another 66 T2DM patients were further evaluated for 8-hydroxy-2′deoxyguanosine (8-OHdG) levels in leukocytic DNA. The average value of 8-OHdG/106 dG was 10.4 in patients with the wild-type genotype, 15.9 in heterozygotes, and 22.3 in homozygotes with the variation (P < 0.001, compared with the wild-type). Therefore, the AluYb8MUTYH polymorphism could be a novel genetic risk factor for T2DM, and accumulated 8-OHdG could contribute to this disease.