CYP2A6 genotypes and coumarin-oxidation phenotypes in a Thai population and their relationship to tobacco smoking.
OBJECTIVE
To investigate the association between polymorphisms in the human CYP2A6 gene, CYP2A6 enzyme activity and the influence of cigarette smoking in a Thai population.


METHODS
Coumarin (5 mg capsule) was administered to 194 healthy Thai subjects. Genetic variation of the CYP2A6 gene was identified using PCR methods. The excreted dose of 7-hydroxycoumarin (as a percentage of the urine concentration) 2 h after administration was calculated as an index of coumarin metabolism.


RESULTS
The frequencies of CYP2A6 alleles *1A, *1B, *4C, *7, *8, *9 and *10 were 34.0, 35.3, 9.3, 6.4, 0.5, 12.1 and 2.4%, respectively. Of the 194 subjects tested, the number (percentages) of Thai participants classified as ultra-rapid, extensive, intermediate and poor metabolizers were 8 (4.1%), 159 (82.0%) 22 (11.3%) and five (2.6%), respectively.


CONCLUSIONS
A relationship between the interindividual differences in coumarin metabolism and genetic polymorphisms of the CYP2A6 gene was observed.
Mahavorasirikul
Wiratchanee
W
Faculty of Allied Health Sciences, Thammasat University, Pathumtanee, Thailand.
Tassaneeyakul
Wichittra
W
Satarug
Soisagwan
S
Reungweerayut
Ronnatrai
R
Na-Bangchang
Chacrin
C
Na-Bangchang
Kesara
K
D000328:Adult; D000483:Alleles; D000925:Anticoagulants / Q000378:metabolism*; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics*; D044466:Asian People / Q000235:genetics*; D003374:Coumarins / Q000378:metabolism*; D065637:Cytochrome P-450 CYP2A6; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D010084:Oxidation-Reduction; D010641:Phenotype; D011110:Polymorphism, Genetic; D012907:Smoking / Q000378:metabolism*; D013785:Thailand; D055815:Young Adult
D000925:Anticoagulants; D003374:Coumarins; C030123:coumarin; D001189:Aryl Hydrocarbon Hydroxylases; C585710:CYP2A6 protein, human; D065637:Cytochrome P-450 CYP2A6