Abstract
Recently, we reported that a simple tandem repeat DNA polymorphism (2G allele) of the skeletal muscle glycogen synthase gene was positively associated with non-insulin-dependent diabetes mellitus (NIDDM) in the Japanese population.
In this study, we confirmed the association and investigated the clinical characteristics of NIDDM patients with the 2G allele. We compared the prevalence of chronic diabetic complications, such as hypertension diabetic retinopathy and diabetic nephropathy in the duration of diabetes in two matched NIDDM groups, with or without the 2G allele. In contrast to the almost identical frequency of hypertension and retinopathy in the two groups, that of nephropathy (continuous proteinuria) was significantly higher in the group with the 2G allele than in that without it (30.8% vs 12.7%, p<0.01) Therefore, we also investigated the degrees of proteinuria in four subgroups classified by the presence or absence of retinopathy or the 2G allele. The frequency of continuous proteinuria was significantly higher in the subgroup which has both retinopathy and the 2G allele. We also investigated the 2G allele frequency in patients with hemodialysis (HD) for either diabetic nephropathy or chronic nephritis. The 2G allele was found more frequently in the HD patients with diabetic nephropathy than in those without it (27% vs 13.8%, p<0.01) and this exceeds the frequency of the 2G allele in nonHD NIDDM patients (20.0%). In conclusion, the 2G allele of the muscle glycogen synthase gene is associated with diabetic nephropathy in the Japanese population.
