Objective: To investigate the effect of the vitamin D receptor (VDR) FokI polymorphism on the clinical presentation of calcium urolithiasis, as a FokI polymorphism in the VDR gene was recently reported to be associated with calcium metabolism disorders.
Patients, subjects and methods: In all, 235 patients with calcium urolithiasis and 231 age- and sex-matched healthy controls were recruited from Kaohsiung Medical University Hospital between June 2003 and February 2005. Clinical information on the age at first onset, stone episodes, stone severity and presence of family history were collected from patients with stones. Any VDR FokI polymorphism was detected using polymerase chain reaction-based restriction analysis.
Results: The frequency of VDR FokI genotypes between the patients and the healthy controls was not significantly different. However, among patients, those with the FF genotype had a significantly higher risk of having more stone episodes (adjusted odds ratio 2.15, 95% confidence interval 1.02-4.54, P = 0.044) and were younger at the first onset (3.23, 1.08-9.63, P = 0.036) than those with the ff genotype.
Conclusion: The VDR FokI polymorphism might be important in the clinical presentation of patients with calcium urolithiasis, especially for the frequency of stone episodes and age at first onset, although it is not associated with the formation of stones.