D18S880 Microsatellite Polymorphism of Carnosinase Gene and Diabetic Nephropathy: A Meta-Analysis

Objective: The aim of this study was to determine whether the CNDP1 (carnosinase gene) D18S880 microsatellite polymorphism confers susceptibility to diabetic nephropathy (DN). Methods: The authors conducted meta-analysis on association between the CNDP1 D18S880 microsatellite polymorphism and DN susceptibility, using fixed and random effects models. Results: A total of nine comparative studies were included in this meta-analysis, which included 4546 DN, 7994 diabetes mellitus (DM), and 1826 healthy (Heal) subjects. Overall, the analysis revealed that the D18S880 microsatellite polymorphism was significantly associated with DN for the five trinucleotide repeat (5L) allele and five leucines repeat (5L-5L) homozygous in the comparisons of DN versus DM (5L: odds ratio [OR] 0.90, 95% confidence interval [CI] 0.84-0.97, p = 0.008; 5L-5L: OR 0.88, 95% CI 0.81-0.97, p = 0.006) and DN versus non-DN (DM + Heal) (5L: OR 0.92, 95% CI 0.86-0.98, p = 0.009; 5L-5L: OR 0.89, 95% CI 0.82-0.96, p = 0.004). The protective effects of the D18S880 polymorphism were similar to those observed in the subgroups of the type 2 DM and the Caucasian population. However, significant association was not found in the type 1 DM population. Conclusions: This meta-analysis confirms that the carnosinase D18S880 microsatellite polymorphism is associated with DN susceptibility, especially in the type 2 DM and the Caucasian population.