Genetic polymorphism of mephenytoin p(4')-hydroxylation: difference between Orientals and Caucasians.
The genetically controlled mephenytoin p(4')-hydroxylation capacity was determined in 118 Caucasians and 70 Orientals. After an oral dose of 50 or 100 mg of racemic mephenytoin, the amount of p(4')-hydroxymephenytoin in 24 h urine was measured by gas chromatography. Bimodal distribution was found with 9/70 (13%) Orientals and 5/118 (4%) Caucasians demonstrating deficient p(4')-hydroxylation. The statistically significant difference between Orientals and Caucasians (P less than 0.05) was accounted for by the high incidence of poor metabolizers among the Japanese subjects, 7/31 (23%). The frequency among Chinese subjects, 2/39 (5%), was similar to the frequency among Caucasians.
D000293:Adolescent; D000328:Adult; D000368:Aged; D044466:Asian People; D002170:Canada; D002681:China / Q000208:ethnology; D002849:Chromatography, Gas; D005260:Female; D006801:Humans; D006827:Hydantoins / Q000378:metabolism*; D006900:Hydroxylation; D007564:Japan / Q000208:ethnology; D008297:Male; D008617:Mephenytoin / Q000378:metabolism* / Q000652:urine; D008875:Middle Aged; D011110:Polymorphism, Genetic; D044465:White People
D006827:Hydantoins; D008617:Mephenytoin