title: CYP2D6 genotype and dextromethorphan hydroxylation phenotype in an Ecuadorian population.
abstract: OBJECTIVE
  Cytochrome P450 2D6 (CYP2D6) genotypes and the dextromethorphan/dextrorphan (DXM/DXT) metabolic ratio (MR), which is a marker of CYP2D6 activity, were studied in 118 unrelated healthy Ecuadorians.
  
  
  METHODS
  Genotyping of CYP2D6 was performed by amplification of entire CYP2D6 gene by XL-PCR for CYP2D6*5 and multiplication alleles and by real time-PCR for CYP2D6 *2, *3, *4, *6, *10, *17, *29, *35, *41, and copy number. The plasma levels of DXM and its metabolite DXT were determined on a high-performance liquid chromatography-UV system.
  
  
  RESULTS
  The proportions of non-functional alleles were 0.4, 10.6, 0.8, 2.1, and 0% for CYP2D6*3, *4, *4 × N, *5, and *6, respectively. Genotypically, only one of the subjects (0.9%) was homozygous for two inactive alleles and phenotypically classified as a poor metabolizer (PM). The MRs (mean ± standard deviation) corresponding to "activity scores" of 0, 0.5, 1, 1.5, 2, and 2.5 were 10.57 (n = 1), 1.63 ± 0.35 (n = 2), 1.16 ± 0.74 (n = 29), 1.00 ± 0.47 (n = 8), 1.24 ± 0.82 (n = 76), and 1.30 ± 0.32 (n = 2), respectively.
  
  
  CONCLUSIONS
  Our data suggest that only 1% of subjects of this Ecuadorian population were PMs and that none were phenotypically ultrarapid metabolizers, which is in agreement with previous findings in other Amerindian populations.
authors.affiliation: CICAB Clinical Research Centre, Extremadura University Hospital and Medical School, Badajoz, Spain.
authors.forename: Pedro
authors.initials: P
authors.lastname: Dorado
authors.forename: Natalia
authors.initials: N
authors.lastname: Heras
authors.forename: Esther
authors.initials: E
authors.lastname: Machín
authors.forename: Francisco
authors.initials: F
authors.lastname: Hernández
authors.forename: Enrique
authors.initials: E
authors.lastname: Teran
authors.forename: Adrián
authors.initials: A
authors.lastname: Llerena
mesh_terms: D000293:Adolescent; D000328:Adult; D000483:Alleles; D000996:Antitussive Agents / Q000097:blood / Q000493:pharmacokinetics*; D001711:Biotransformation; D019389:Cytochrome P-450 CYP2D6 / Q000235:genetics* / Q000378:metabolism; D003915:Dextromethorphan / Q000097:blood / Q000493:pharmacokinetics*; D003917:Dextrorphan / Q000097:blood; D004484:Ecuador; D005260:Female; D018628:Gene Dosage; D005787:Gene Frequency; D056726:Genetic Association Studies; D006801:Humans; D006900:Hydroxylation; D008297:Male; D011110:Polymorphism, Genetic; D055815:Young Adult
chemical_list: D000996:Antitussive Agents; D003917:Dextrorphan; D003915:Dextromethorphan; D019389:Cytochrome P-450 CYP2D6
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