Identification of a null allele of cytochrome P450 3A7: CYP3A7 polymorphism in a Korean population.
Cytochrome P450 3A7 (CYP3A7) is expressed in the human fetal liver and plays a role in the metabolism of hormones, drugs, and toxic compounds. Genetic variants of CYP3A7 are associated with serum estrone level, bone density, and hepatic CYP3A activity in adults. We analyzed the genetic variations of CYP3A7 in a Korean population. From direct sequencing of all exons and flanking regions of the CYP3A7 gene in 48 Koreans, we found five genetic variants, including three novel variants. One variant, a thymidine insertion in exon 2 (4011insT), causes premature termination of CYP3A7 translation, which may result in a null phenotype. The novel variant was assigned to the CYP3A7*3 allele by the CYP allele nomenclature committee. For further screen of this novel variant in other ethnic populations, we used pyrosequencing to analyze an additional 185 Koreans, 100 African Americans, 100 Caucasians, and 159 Vietnamese for the presence of this variant. The variant was not found in any other individuals, except for one Korean subject. The frequencies of two known functional alleles, CYP3A7*2 and CYP3A7*1C, were 26 and 0%, respectively, in Koreans. The frequencies of the functional CYP3A7 polymorphisms in Koreans were significantly different from those in Caucasians and African Americans. This is the first report of a null-type allele of the CYP3A7 gene. It also provides population-level genetic data on CYP3A7 in Koreans to reveal the wide ethnic variation in CYP3A7 polymorphism.
Lee
Sang Seop
SS
Department of Pharmacology and PharmacoGenomics Research Center, Inje University College of Medicine, Busan, Korea.
Jung
Hyun-Ju
HJ
Park
Jung Soon
JS
Cha
In-June
IJ
Cho
Doo-Yeoun
DY
Shin
Jae-Gook
JG
D000483:Alleles; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics*; D044466:Asian People / Q000235:genetics*; D001483:Base Sequence; D051544:Cytochrome P-450 CYP3A; D004252:DNA Mutational Analysis; D006579:Heterozygote; D006801:Humans; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D056910:Republic of Korea
D001189:Aryl Hydrocarbon Hydroxylases; C103123:CYP3A7 protein, human; D051544:Cytochrome P-450 CYP3A