The association between single nucleotide polymorphism in vitamin D receptor and calcium oxalate urolithiasis in dogs

BACKGROUND: Polymorphisms of the vitamin D receptor (VDR) are associated with calcium oxalate (CaOx) nephrolithiasis in humans. OBJECTIVES: To investigate the association between VDR polymorphisms and susceptibility to CaOx urolithiasis in dogs. ANIMALS: Thirty‐five dogs with CaOx urolithiasis were compared with 40 stone‐free dogs. METHODS: This was a case‐control study. Two VDR gene polymorphisms (rs851998024 and rs852900542) were detected by specific TaqMan real‐time polymerase chain reaction assay, and their relationship with serum 1,25‐dihydroxyvitamin D, serum and urinary electrolyte concentrations was evaluated. RESULTS: The distribution of the rs852900542 polymorphism was significantly different between the case and the control dogs (x (2) = 6.369, P = .04). Dogs with a CC or CT genotype had an increased risk of CaOx stones than those with the TT genotype (odds ratio = 3.82, 95% confidence interval 1.04‐13.98). The CaOx dogs with the TT genotype had a significantly lower urinary calcium‐to‐creatinine ratio than the CT+CC genotypes. 1,25‐(OH)2D concentrations did not differ between the cases and the controls (308.7 ± 217.4 vs 286.7 ± 185.1 pg/mL, P = .45). CONCLUSIONS AND CLINICAL IMPORTANCE: This finding suggests that vitamin D metabolism might play a role in CaOx stone formation in dogs.