OBJECTIVETo evaluate the role of polymorphism in the neurogenic differentiation factor 1(Neuro D) gene in Chinese patients with type 2 diabetes mellitus.

METHODSThe genotypes of codon 45 variant (GCC-->ACC) in the Neuro D gene were determined by mismatch PCR-restriction fragment length polymorphism assay in 448 Chinese, including 124 subjects with normal glucose tolerance and 324 patients with type 2 diabetes mellitus. The diabetic patients were divided into two groups cutting off with the age of 40 at onset.

RESULTSNo homozygote of the Ala45Thr variant was found in these subjects. The frequencies of AT heterozygous type were significantly higher in early-onset type 2 diabetic group than those in the control group and in the late-onset type 2 diabetic group (chi(2)=7.85, P=0.005; chi(2)=8.81, P=0.003). The frequencies of Thr45 allele in the early-onset type 2 diabetic group were significantly different from those of the control group (13.4% vs 5.2%, chi(2)=7.15, P=0.008) and the late-onset type 2 diabetic group (13.4% vs 5.8%, chi(2)=8.13, P=0.004). The presence of Thr45 allele was shown to have an association with early-onset type 2 diabetes (OR=2.52, 95% CI: 1.42-4.49). Furthermore, the subjects carrying the variant appeared to have lower serum concentration of C-peptide in diabetic group. However, the frequencies of polymorphism genotypes of Neuro D gene showed no difference between the late-onset type 2 diabetic group and the control group.

CONCLUSIONThe genetic polymorphism in the Neuro D is associated with the development of early-onset type 2 diabetes. The presence of Thr45 allele may represent a risk factor for early-onset type 2 diabetes among Chinese.