[Correlation of genetic polymorphism of cytochrome P4502D6 with dextromethorphan oxidative metabolism in Chinese]

Abstract

Objective: To determine the genetic mechanism of dextromethorphan oxidative polymorphism in Chinese subjects.

Methods: CYP2D6 genotype was analyzed by polymerase chain reaction (PCR) and Hph I restriction fragment length polymorphism (RFLP) techniques in 119 healthy Chinese subjects.

Results: The gene frequency of CYP2D6*10B was 58.4%, including 13(10.9%) of homozygous wild type(w/w), 33 (27.7%) of homozygous mutant(m/m), and 73(61.3%) of heterozygous genotypes(m/w). Twenty-nine subjects out of 42 intermediate metabolizers(70%) of dextromethorphan were homozygous for CYP2D6*10B. One poor metabolizer subject also showed an m/m genotype. Besides, 10 Chinese subjects were tested and excluded for the presence of any of the six mutant alleles associated with poor metabolism of CYP2D6 in Caucasians.

Conclusion: The CYP2D6*10B allele containing the C(188)--> T mutation is the major cause of CYP2D6 polymorphism in relation to diminished dextromethorphan oxidative capacity in Chinese subjects.