ApaL1 urokinase and Taq1 vitamin D receptor gene polymorphisms in first-stone formers, recurrent stone formers, and controls in a Caucasian population

The purpose of this study was to determine differences in genotype distribution and allele frequency of urokinase and vitamin D receptor (VDR) single nucleotide polymorphisms (SNPs) between first-stone formers, recurrent stone formers, and controls in a Caucasian population. A total of 86 first-stone formers, 78 recurrent stone formers, and 167 controls were included. Urokinase and VDR SNPs were tested by gene amplification followed by ApaL1 and Taq1 endonuclease digestion, respectively. Baseline variables, genotype, and allele frequencies were compared between the three groups, using descriptive statistics. Adjusted odds ratios were calculated to estimate the risk for recurrent urolithiasis associated with genotypes. We found that differences in the distribution of ApaL1 SNP and Taq1 SNP genotypes were statistically different between recurrent stone formers and first-stone formers, and between recurrent stone formers and controls. Allele frequency analysis showed that the T allele for ApaL1 SNP and the C allele for Taq1 SNP were significantly associated with recurrent urolithiasis. For Taq1 SNP, logistic regression analysis showed that the C/C genotype was associated with a more than threefold higher risk for recurrent urolithiasis. We conclude that ApaL1 and Taq1 SNPs of the urokinase and VDR genes are associated with recurrent urolithiasis in a Caucasian population.