title: Variability in kidney stone incidence between black and white South Africans: AGT Pro11Leu polymorphism is not a factor.
abstract: OBJECTIVE
  Kidney stone disease is rare in the South African black (B) population and more prevalent in the white (W) population. Genetic studies have not previously examined this anomaly. The AGT Pro11Leu polymorphism in the alanine:glyoxylate aminotransferase (AGT) enzyme has been suggested as possibly playing a role in the pathogenesis of idiopathic calcium oxalate kidney stones. The present study was undertaken to investigate whether differences occur in the frequency of this polymorphism in subjects of both race groups.
  
  
  METHODS
  Healthy B (n=60) and W (n=60) male subjects each provided early morning spot urine, blood, and buccal cell samples. The AGT Pro11Leu locus was amplified using the polymerase chain reaction and polymorphism was genotyped using a restriction fragment length polymorphism.
  
  
  RESULTS
  There was no difference in the frequency of the AGT Pro11Leu polymorphism, and the major allele (C) was present at a frequency of 0.82 in B and 0.83 in W. Thus, the most common genotype homozygous normal CC genotype was observed at similar frequencies in both groups (0.68 and 0.65 in B and W, respectively), as were the heterozygous CT genotype (CT) and the homozygous variant TT genotype (TT) genotypes (0.33 & 0.02 and 0.28 & 0.03 in B and W, respectively). Neither urinary oxalate nor any other component in the two groups was correlated with the frequency of the AGT Pro11Leu polymorphism.
  
  
  CONCLUSIONS
  Our data imply that the AGT Pro11Leu polymorphism is not directly responsible for the low incidence of stone formation in B. We conclude that other factors must be instrumental in protecting the B population from urolithiasis.
authors.affiliation: 1 Department of Chemistry, University of Cape Town , Cape Town, South Africa .
authors.forename: Takalani
authors.initials: T
authors.lastname: Theka
authors.forename: Allen L
authors.initials: AL
authors.lastname: Rodgers
authors.forename: Dawn
authors.initials: D
authors.lastname: Webber
authors.forename: Colleen
authors.initials: C
authors.lastname: O'Ryan
mesh_terms: D000293:Adolescent; D000328:Adult; D000483:Alleles; D044383:Black People / Q000235:genetics* / Q000706:statistics & numerical data; D002129:Calcium Oxalate / Q000652:urine; D005838:Genotype; D006801:Humans; D015994:Incidence; D007669:Kidney Calculi / Q000453:epidemiology / Q000235:genetics* / Q000652:urine; D008297:Male; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D013019:South Africa / Q000453:epidemiology; D000637:Transaminases / Q000235:genetics*; D044465:White People / Q000235:genetics* / Q000706:statistics & numerical data; D055815:Young Adult
chemical_list: D002129:Calcium Oxalate; D000637:Transaminases; C019635:Alanine-glyoxylate transaminase