title: Association of vitamin D receptor-gene (FokI) polymorphism with calcium oxalate nephrolithiasis.
abstract: OBJECTIVE
  Formation of kidney stones is still not understood but is hypothesized to be associated with the vitamin D receptor gene (VDR). In order to assess the eventual role of VDR start-codon FokI polymorphism in stone formation, we evaluated the association between calcium stone disease and this polymorphism in a North Indian population.
  
  
  METHODS
  A control group comprised of 166 healthy individuals (age range 22-58 years) and a group of 138 patients with calcium oxalate stones (age range 21-72 years) were examined. The polymorphism was detected using polymerase chain reaction-based restriction analysis. An unexcisable length of 265 bp (CC) and two fragments of 169 bp and 96 bp (TT) were obtained by FokI restriction digestion.
  
  
  RESULTS
  There was a statistically significant difference between the control and patient groups (X2 test, P<0.001) for the genotype of the VDR FokI start-codon polymorphism. The odds ratio (with 95% CI) for the C allele in those at risk of stone disease was 1.654 (1.041, 2.628). The VDR frequency distribution was also statistically significant (P<0.001) in case of male sex. The frequency distribution for this genetic polymorphism was not statistically different in normocalciuric and hypercalciuric stone patients (P=0.355).
  
  
  CONCLUSIONS
  The VDR FokI polymorphism may be a good candidate for a marker for calcium oxalate-stone disease. These findings may contribute a small piece to the understanding of the pathogenesis of urinary calculi.
authors.affiliation: Department of Urology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, India.
authors.forename: Hemant Kumar
authors.initials: HK
authors.lastname: Bid
authors.forename: Ajay
authors.initials: A
authors.lastname: Kumar
authors.forename: Rakesh
authors.initials: R
authors.lastname: Kapoor
authors.forename: Rama D
authors.initials: RD
authors.lastname: Mittal
mesh_terms: D000328:Adult; D000368:Aged; D002129:Calcium Oxalate / Q000652:urine*; D018387:Codon, Initiator / Q000235:genetics; D005260:Female; D005787:Gene Frequency; D005819:Genetic Markers; D005838:Genotype; D006801:Humans; D007669:Kidney Calculi / Q000097:blood / Q000235:genetics* / Q000652:urine; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic / Q000235:genetics*; D018167:Receptors, Calcitriol / Q000097:blood / Q000235:genetics*; D012189:Retrospective Studies
chemical_list: D018387:Codon, Initiator; D005819:Genetic Markers; D018167:Receptors, Calcitriol; D002129:Calcium Oxalate