title: Linkage disequilibrium between the CYP2C19*17 allele and wildtype CYP2C8 and CYP2C9 alleles: identification of CYP2C haplotypes in healthy Nordic populations.
abstract: OBJECTIVE
  To determine the distribution of clinically important CYP2C genotypes and allele frequencies in healthy Nordic populations with special focus on linkage disequilibrium.
  
  
  METHODS
  A total of 896 healthy subjects from three Nordic populations (Danish, Faroese, and Norwegian) were genotyped for five frequent and clinically important CYP2C allelic variants: the defective CYP2C8*3, CYP2C9*2, CYP2C9*3, and CYP2C19*2 alleles, and the CYP2C19*17 allele that causes rapid drug metabolism. Linkage disequilibrium was evaluated and CYP2C haplotypes were inferred in the entire population.
  
  
  RESULTS
  Ten CYP2C haplotypes were inferred, the most frequent of which (49%) was the CYP2C wildtype haplotype carrying CYP2C8*1, CYP2C9*1, and CYP2C19*1. The second most frequent haplotype (19%) is composed of CYP2C19*17, CYP2C8*1, and CYP2C9*1. This predicted haplotype accounts for 99.7% of the CYP2C19*17 alleles found in the 896 subjects.
  
  
  CONCLUSIONS
  CYP2C19*17 is a frequent genetic variant in Nordic populations that exists in strong linkage disequilibrium with wildtype CYP2C8*1 and CYP2C9*1 alleles, which effectively makes it a determinant for a haplotype exhibiting an efficient CYP2C substrate metabolism.
authors.affiliation: Institute of Public Health, Clinical Pharmacology, University of Southern Denmark, Odense, Denmark. rpedersen@health.sdu.dk
authors.forename: Rasmus S
authors.initials: RS
authors.lastname: Pedersen
authors.forename: Charlotte
authors.initials: C
authors.lastname: Brasch-Andersen
authors.forename: Sarah C
authors.initials: SC
authors.lastname: Sim
authors.forename: Troels K
authors.initials: TK
authors.lastname: Bergmann
authors.forename: Jónrit
authors.initials: J
authors.lastname: Halling
authors.forename: Maria S
authors.initials: MS
authors.lastname: Petersen
authors.forename: Pál
authors.initials: P
authors.lastname: Weihe
authors.forename: Hege
authors.initials: H
authors.lastname: Edvardsen
authors.forename: Vessela N
authors.initials: VN
authors.lastname: Kristensen
authors.forename: Kim
authors.initials: K
authors.lastname: Brøsen
authors.forename: Magnus
authors.initials: M
authors.lastname: Ingelman-Sundberg
mesh_terms: D000483:Alleles; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics*; D065731:Cytochrome P-450 CYP2C19; D065727:Cytochrome P-450 CYP2C8; D065729:Cytochrome P-450 CYP2C9; D003718:Denmark; D006239:Haplotypes; D006801:Humans; D015810:Linkage Disequilibrium; D009664:Norway
chemical_list: C450260:CYP2C9 protein, human; D065729:Cytochrome P-450 CYP2C9; D001189:Aryl Hydrocarbon Hydroxylases; C045793:CYP2C19 protein, human; C450259:CYP2C8 protein, human; D065731:Cytochrome P-450 CYP2C19; D065727:Cytochrome P-450 CYP2C8