Frequencies of thiopurine S-methyltransferase mutant alleles (TPMT*2, *3A, *3B and *3C) in 151 healthy Japanese subjects and the inheritance of TPMT*3C in the family of a propositus.
OBJECTIVE
To determine the frequencies of four thiopurine S-methyltransferase (TPMT) mutant alleles, TPMT*2, *3A, *3B and *3C in a normal Japanese population.


METHODS
Genotypes were determined in 151 Japanese subjects and in six family members of a propositus using polymerase chain reaction (PCR)-restriction fragment length polymorphism and allele-specific PCR assays.


RESULTS
Only one TPMT*3C heterozygote was identified (gene frequency 0.3%). TPMT*2, *3A and *3B were not detected. In addition, TPMT*3C was found to have been inherited from the mother and passed on to the son of the propositus.


CONCLUSIONS
TPMT*3C appears to be most prevalent among the known mutant allele of TPMT in a Japanese population which may have some relevance for the treatment of Japanese patients with thiopurine drugs.
Kubota
T
T
Research Testing Department, SRL, Inc., Hachioji-shi, Tokyo, Japan.
Chiba
K
K
D000328:Adult; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D007564:Japan; D008780:Methyltransferases / Q000145:classification / Q000235:genetics*; D008875:Middle Aged; D009154:Mutation
D008780:Methyltransferases; C022745:thiopurine methyltransferase