title: Thiopurine methyltransferase polymorphisms in a Brazilian population.
abstract: Thiopurine methyltransferase (TPMT) catalyses the S-methylation of thiopurine drugs. Low-activity phenotypes are correlated with several mutations in the TPMT gene. Polymorphisms of TPMT have been reported for Caucasians, African-Americans and Asians. Since ethnic differences have been demonstrated worldwide, it remains to be elucidated in Brazil. The Brazilian population is the result of five centuries of interethnic crosses between peoples from almost all continents as well as autochthonous Amerindians, all forming the fifth largest and one of the most heterogeneous populations in the world. The frequency of six allelic variants of the TPMT gene, *2 (G238C) (2.2%), *3A (G460A and A719G) (1.5%), *3B (G460A) (0.2%), *3C (A719G) (1.0%), *5 (0%) and *6 (0%) were determined in Brazilian subjects using polymerase chain reaction (PCR)-RFLP and allele-specific PCR-based assays. This study provides the first analysis of TPMT mutant allele frequency in a sample of the Brazilian population.
authors.affiliation: Departamento de Farmacologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors.forename: W L
authors.initials: WL
authors.lastname: Boson
authors.forename: M A
authors.initials: MA
authors.lastname: Romano-Silva
authors.forename: H
authors.initials: H
authors.lastname: Correa
authors.forename: R P
authors.initials: RP
authors.lastname: Falcão
authors.forename: P V
authors.initials: PV
authors.lastname: Teixeira-Vidigal
authors.forename: L
authors.initials: L
authors.lastname: De Marco
mesh_terms: D044466:Asian People / Q000208:ethnology / Q000235:genetics; D044383:Black People / Q000208:ethnology / Q000235:genetics; D001938:Brazil / Q000208:ethnology; D005787:Gene Frequency / Q000235:genetics; D006801:Humans; D008780:Methyltransferases / Q000235:genetics*; D009154:Mutation; D011110:Polymorphism, Genetic / Q000235:genetics*; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000201:enzymology / Q000235:genetics; D044465:White People / Q000208:ethnology / Q000235:genetics; D001741:Black or African American
chemical_list: D008780:Methyltransferases; C022745:thiopurine methyltransferase