Association of CC chemokine ligand 5 genotype with urinary albumin excretion in the non-diabetic Japanese general population: the Takahata study.

Albuminuria is an early marker of vascular damage, and its development in diabetic nephropathy is associated with genotype of inflammatory CC chemokine ligand 5 (CCL5). This study investigated whether the association of CCL5 and albuminuria is a general phenomenon. We characterized a Japanese population consisting of 2,749 non-diabetic individuals over 40 years in Takahata, Japan. The urine albumin-creatinine ratio (UACR) was obtained from morning spot urine. We genotyped SNPs within the CCL5 gene that displayed frequent minor allele frequencies in Japanese (i.e., rs2107538, rs2280789, rs3817655 and rs9909416). Assessment of possible association and linkage disequilibrium (LD) revealed that all four SNP genotypes are correlated significantly with UACR (P = 0.004-0.005), and these four SNPs variations showed an obvious consistency of genotypes by detecting almost complete linkage disequilibrium (D' = 1 and r (2) > 0.95). We found two exclusive haplotypes in the CCL5 gene (haplotype1: rs2107538G/rs2280789T/rs3817655T/rs9909416G, frequency 0.64 and haplotype2: rs2107538A/rs2280789C/rs3817655A/rs9909416A, frequency 0.35) among the population. A significant association with elevated UACR was identified with haplotype1 (P = 0.002). Homozygotes for haplotype1 displayed strikingly-elevated UACR (48.5 +/- 6.6 mg/g, n = 1,116) compared to the rest (28.6 +/- 1.6 mg/g, n = 1,530) (P = 0.001). In conclusion, these results suggested that genetic variation of CCL5 might be an important risk factor for albuminuria in the non-diabetic Japanese general population.