Reis Marcelo, Santoro Ana, Suarez-Kurtz Guilherme
Divisão de Farmacologia, Coordenação de Presquisa, Instituto Nacional de Câncer, Rio de Janeiro, Brazil.
Pharmacogenetics. 2003 Jun;13(6):371-3. doi: 10.1097/00008571-200306000-00009.
The polymorphism of thiopurine methyltransferase (TPMT) was studied in 306 healthy Brazilians who were classed, on the basis of self-declared colour and ancestry, as Euro-derived (n = 81), Afro-derived (n = 18) or having interethnic admixture (n = 204). TPMT activity (range 0.17-25.93 U) displayed a trimodal distribution of high (> 11.3 U; 9% of individuals), intermediate (5-11.3 U; 9.8%) and low (0.17 U; 0.3%) phenotypes. The occurrence of the TPMT mutations 238G>C, 460G>A and 719A>G was investigated in all individuals with low or intermediate phenotype, and in 43 with high-activity phenotype. None and two mutant alleles were associated with high- or low-activity phenotypes, respectively, whereas one mutant allele was detected in 26 of the 30 intermediate phenotype individuals. The allele frequencies of TPMT2, TPMT3A and TPMT3C did not differ between individuals classed as Euro-derived (0.76%, 2.03% and 2.54%, respectively) or having interethnic admixture (0.60%, 1.81% and 1.81%, respectively). Furthermore, within each of these groups, the frequencies of TPMT3A and TPMT*3C were not significantly different.
在306名健康的巴西人中研究了硫嘌呤甲基转移酶（TPMT）的多态性，这些人根据自我申报的肤色和血统被分类为欧洲裔（n = 81）、非洲裔（n = 18）或具有种族间混合血统（n = 204）。TPMT活性（范围为0.17 - 25.93 U）呈现出高活性（> 11.3 U；占个体的9%）、中等活性（5 - 11.3 U；占9.8%）和低活性（< 5 U；占0.3%）三种表型的三峰分布。对所有低活性或中等活性表型的个体以及43名高活性表型的个体进行了TPMT突变238G>C、460G>A和719A>G的检测。分别有0个和2个突变等位基因与高活性或低活性表型相关，而在30名中等活性表型个体中有26名检测到1个突变等位基因。TPMT2、TPMT3A和TPMT3C的等位基因频率在欧洲裔个体（分别为0.76%、2.03%和2.54%）和具有种族间混合血统的个体（分别为0.60%、1.81%和1.81%）之间没有差异。此外，在这些组中的每一组内，TPMT3A和TPMT*3C的频率没有显著差异。
