title: High prevalence of cytochrome P450 2A6*1A alleles in a black African population of Ghana.
abstract: OBJECTIVE
  We investigated the frequencies of the functionally important variants of the CYP2A6 gene in black African populations.
  
  
  METHODS
  Using genomic DNA sequencing, polymerase chain reaction (PCR)-restriction fragment length polymorphism and allele-specific PCR, the allele frequencies of CYP2A6 *1A, *1B, *2, *4A, *5, *6, *7, *8, *9, *10 and * 11 among 120 black Africans- including 105 Ghanaians, 12 Nigerians, 2 Ivorians and 1 Ugandan-were determined.
  
  
  RESULTS
  The allele frequencies were 80.5% for CYP2A6*1A, 11.9% for CYP2A6*1B, 1.9% for CYP2A6*4A and 5.7% for CYP2A6*9 in the Ghanaian subjects. No subject homozygous for the CYP2A6*4A allele, a whole gene deletion type of polymorphism prevalent among Orientals, was found. Furthermore, CYP2A6 variants such as *2, *5, *6, *7, *8, *10 and *11 were absent in these black African populations.
  
  
  CONCLUSIONS
  This study provides, for the first time, the results of the analysis of CYP2A6 allele frequency in black African populations and confirms large ethnic differences in the polymorphic CYP2A6 gene.
authors.affiliation: Laboratory of Drug Metabolism, Graduate School of Pharmaceutical Sciences, Hokkaido University, N12W6, Kita-ku, Sapporo 060-0812, Japan.
authors.forename: Maxwell Afari
authors.initials: MA
authors.lastname: Gyamfi
authors.forename: Masaki
authors.initials: M
authors.lastname: Fujieda
authors.forename: Kazuma
authors.initials: K
authors.lastname: Kiyotani
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamazaki
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Kamataki
mesh_terms: D000328:Adult; D000368:Aged; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics*; D044383:Black People; D065637:Cytochrome P-450 CYP2A6; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D005869:Ghana; D006801:Humans; D008297:Male; D008875:Middle Aged; D006899:Mixed Function Oxygenases / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length
chemical_list: D006899:Mixed Function Oxygenases; D001189:Aryl Hydrocarbon Hydroxylases; C585710:CYP2A6 protein, human; D065637:Cytochrome P-450 CYP2A6