title: Toxicity of azathioprine: why and when? analysis of the prevalence of polymorphism in Joinville, SC, Brazil.
abstract: BACKGROUND
  The use of thiopurine drugs such as azathioprine and 6-mercaptopurine has become quite common in the treatment of inflammatory bowel disease, transplantation and acute leukemias. Despite their effectiveness, these drugs are capable of causing drug-induced toxicity with the risk of death by myelosuppression. It is now known that these complications occur because of genetic polymorphisms of the thiopurinemethyltransferase (TPMT) enzyme, responsible for its metabolism.
  
  
  OBJECTIVE
  To assess the prevalence of thiopurine methyltransferase polymorphisms in the population of Joinville, SC, Brazil.
  
  
  METHODS
  We analyzed the frequency of four main allelic variants of the TPMT gene in 199 blood donors from Joinville, from February to April 2010.
  
  
  RESULTS
  The normal allele ("wild-type") was found in 93.9% of subjects studied. TPMT variants were detected in 12 subjects (6.03%).
  
  
  CONCLUSIONS
  From this study, it was estimated at 6% the risk of toxicity by the administration of azathioprine and 6-mercaptopurine to patients in Joinville.
authors: University of Joinville Region (UNIVILLE), Program in Health and Environment, Department of Hematology, Joinville, SC, Brazil. gabigastal22@gmail.com
authors: Gabriela Roncone
authors: GR
authors: Gastal
authors: Simone
authors: S
authors: Moreira
authors: Caroline Furtado
authors: CF
authors: Noble
authors: Leslie Ecker
authors: LE
authors: Ferreira
authors: Paulo Henrique Condeixa de
authors: PH
authors: França
authors: Mauro
authors: M
authors: Pinho
mesh_terms: D000328:Adult; D001379:Azathioprine / Q000009:adverse effects*; D001938:Brazil; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D015122:Mercaptopurine / Q000009:adverse effects*; D008780:Methyltransferases / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics*; D012307:Risk Factors
chemical_list: D015122:Mercaptopurine; D008780:Methyltransferases; C022745:thiopurine methyltransferase; D001379:Azathioprine