title: High arsenic metabolic efficiency in AS3MT287Thr allele carriers.
abstract: OBJECTIVE
  Epidemiological data indicate the existence of wide interindividual differences in arsenic metabolism. It has recently been shown that arsenic(III)methyltransferase (AS3MT) enzyme catalyses the methylation of arsenite and monomethylarsonous acid (MMA). Thus, genetic variations in the AS3MT gene could explain, at least partly, the interindividual variation in the response to arsenic exposure. In an earlier study, we have demonstrated that the AS3MT Met(287)Thr (C/T) polymorphism affected the urinary arsenic profile in a Chilean group of men (n=50) occupationally exposed to arsenic.
  
  
  METHODS
  To confirm, the influence of the Met(287)Thr polymorphism in the metabolism of arsenic, a total of 207 Chilean men working at the copper industry were genotyped and their urinary profiles determined.
  
  
  RESULTS
  The results confirm that Met(287)Thr polymorphism does influence arsenic metabolism in this population. Those carriers of the variant ((287)Thr) had a higher methylation efficiency, excreting 4.63% more MMA in urine (P=0.0007) and presenting a 2.98 times higher odd of excreting levels of MMA over the standard (P=0.011) than the participants homozygous for the normal allele.
  
  
  CONCLUSIONS
  We can conclude that individuals with the (287)Thr variant display increased arsenic methylation; thus, those participants might be at increased risk for the toxic and genotoxic effects of arsenic exposure.
authors.affiliation: Grup de Mutagènesi, Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona, Bellaterra, Spain.
authors.forename: Alba
authors.initials: A
authors.lastname: Hernández
authors.forename: Noel
authors.initials: N
authors.lastname: Xamena
authors.forename: Chandra
authors.initials: C
authors.lastname: Sekaran
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tokunaga
authors.forename: Adriana
authors.initials: A
authors.lastname: Sampayo-Reyes
authors.forename: Domingo
authors.initials: D
authors.lastname: Quinteros
authors.forename: Amadeu
authors.initials: A
authors.lastname: Creus
authors.forename: Ricardo
authors.initials: R
authors.lastname: Marcos
mesh_terms: D000328:Adult; D000483:Alleles; D001149:Arsenates / Q000652:urine*; D003300:Copper; D005838:Genotype; D006801:Humans; D008297:Male; D008745:Methylation; D008780:Methyltransferases / Q000235:genetics* / Q000378:metabolism; D008875:Middle Aged; D008906:Mining; D011110:Polymorphism, Genetic
chemical_list: D001149:Arsenates; D003300:Copper; D008780:Methyltransferases; C505756:AS3MT protein, human; C025657:arsenic acid