Abstract

BACKGROUND: The association of genetic polymorphisms of klotho gene with aging has not been thoroughly examined. Previous studies showed that longevity in the Uygurs was considerably greater than in Kazaks in Xinjiang. This study aimed to investigate the difference of renal function and Klotho gene polymorphisms between Kazak and Uygur normal populations in Xinjiang, China.

MATERIAL AND METHODS: A total of 249 Uygur and 386 Kazak clinically normal subjects were included in this study. Four single-nucleotide polymorphisms (rs1207568, rs564481, rs9527025, and rs9536314) of the klotho gene were genotyped using the ABI SNaPshot method. Estimated glomerular filtration rate (eGFR) was calculated according to the Chinese simplified MDRD equation.

RESULTS: There were significant differences between Kazak and Uygur healthy populations in both allele frequencies and genotype distributions in rs9527025 and rs9536314 (P<0.05, respectively). When the subjects were divided into 2 groups according to the genotypes of the klotho gene polymorphism, in the GA+AA genotype distributions of the rs1207568, the differences I serum creatinine and estimated glomerular filtration rate between the Kazak and Uygur groups were statistically significant (P<0.05, respectively). In CC genotype of rs564481, serum creatinine was significantly higher in Kazaks compared with Uygurs (P<0.05). In GG genotype of rs9527025, serum creatinine was significantly higher in the Kazak group compared with the Uygur group (P<0.05), as well as in CG+CC genotype of rs9527025 (P<0.05). Serum creatinine was significantly higher in the Kazak group compared with the Uygur group in TT genotype of rs9536314 (P<0.05), as was GT+GG genotype of rs9536314. Haplotype analysis indicated that the frequencies of ACGT, GTGT, and GCCG haplotypes were significantly different between Kazak and Uygur healthy populations (P=0.04, P=0.018, P=0.000, respectively).

CONCLUSIONS: Significant differences in klotho gene rs9527025 and rs9536314 polymorphisms were found between the Uygur and Kazak populations.

Keywords: China - ethnology, Ethnic Groups, Gene Frequency, Genotype, Glomerular Filtration Rate, Glucuronidase - genetics, Haplotypes, Kidney - metabolism, Kidney Function Tests, Mutation, Polymorphism, Single Nucleotide