Phenotyping and genotyping studies of thiopurine S-methyltransferase in Kazaks.
OBJECTIVE
This study was conducted to investigate the thiopurine S-methyltransferase (TPMT) activity distribution and gene mutations in Kazaks, and compared the results with those of other ethnic groups.


METHODS
Erythrocyte TPMT activity was measured in Kazaks (n = 327) via a validated high-performance liquid chromatography assay. Polymerase chain reaction-based methods were used to analyze three commonly reporter-inactivating mutations: G238C, G460A, and A719G.


RESULTS
Unimodal distribution of TPMT activity was found in Kazaks. Six TPMT*3C heterozygotes and two TPMT*3A heterozygotes were found in 327 Kazaks, with allele frequencies of 0.9 and 0.3%, respectively. The subjects with TPMT*3A and TPMT*3C heterogygotes had substantial TPMT activity over the range of 6.40-11.75 U/ml RBC.


CONCLUSIONS
Unlike in most Caucasians, TPMT*3C is a common mutant allele in Kazaks, whereas TPMT*3A is a rare mutant allele. Further studies are needed to explore the clinical impact of these TPMT mutants to thiopurine therapy in Kazak patients.
Wei
Hong
H
Department of Clinical Pharmacy, Shenzhen Children's Hospital, Shenzhen, People's Republic of China.
Zhou
Shufeng
S
Li
Chengrong
C
Zhang
Jianping
J
Wu
Jueheng
J
Huang
Min
M
D000293:Adolescent; D000328:Adult; D000483:Alleles; D005260:Female; D005838:Genotype; D006801:Humans; D007623:Kazakhstan; D008297:Male; D008780:Methyltransferases / Q000235:genetics*; D008875:Middle Aged; D009154:Mutation; D010641:Phenotype
D008780:Methyltransferases; C022745:thiopurine methyltransferase