Objective: To investigate the association between a 894 G-->T mutation at exon 7 and a 27 base pair(bp) repeat polymorphism in intron 4 of the eNOS gene and diabetic nephropathy in Chinese.
Methods: A case control study of 228 Chinese subjects (including 143 type 2 diabetes mellitus with or without nephropathy and 85 normal controls) was performed. The number of 894 G-->T mutation allele and 27 bp repeat polymorhism alleles were determined by polymerasechain reaction restriction fragment lenth polymorphism(PCR-RFLP) method and PCR combined with 4% agarose electrophoresis.
Results: The frequency of the T allele and TG genotype at exon 7 and the a allele and ab genotype in intron 4 were significantly higher in diabetic nephropathy positive (DN+) group than in diabetic nephropathy negative (DN-) group and control subjects(P < 0.05). Diabetic patients with coexistence of the T and a alleles had a higher incidence of diabetic nephropathy(P < 0.05) than those with only one of the two alleles or without any of the two alleles. Multivariate logistic regression analysis showed that blood glucose, GHbA1c, SBP, TC, 894 G-->T mutation at exon 7 and a 27 base pair(bp) repeat polymorphism in intron 4 of the eNOS gene are independent risk factors for diabetic nephropathy.
Conclusions: The T allele at exon 7 and a allele in intron 4 are related to diabetic nephropathy in Chinese patients with type with 2 diabetes mellitus. The incidence of diabetic nephropathy is higher in patients who have both T and a alleles than patients who have either T or a allele alone.