CXCL12 and diabetic kidney disease: To test the influence of SDF-1/CXCR4 gene variations on the susceptibility to DKD, genotypes of four SNPs from the SDF-1 gene (rs1801157, rs2297630, rs2839693, and rs266085) and of two SNPs from the CXCR4 gene (rs2228014 and rs6430612) were surveyed in our cohorts.