title: C3435T polymorphism of MDR1 gene with warfarin resistance.
abstract: BACKGROUND
  Some patients show warfarin resistance needing more than 70 mg of warfarin per week. In this study, we examined if C3435T polymorphism of MDR1 gene could be a factor of warfarin resistance.
  
  
  METHODS
  We examined 196 blood specimens from the patients who took warfarin more than 42 mg/week for at least 1 year. The subjects consisted of 74 European Americans, 59 African Americans, 42 Hispanic Americans and 21 Asian Americans. Genotype of C3435T polymorphism was determined by using real-time polymerase chain reaction (PCR).
  
  
  RESULTS
  Ninety (45.9%) of the 196 patients had C3435T genotype and the remaining patients had C3435C genotype (35.7%) and T3435T genotype (18.4%). Mean dose of warfarin of patients with C3435C, C3435T and T3435T genotypes were 59.5mg/week, 56.9 mg/week and 55.6 mg/week, respectively. There was no statistical difference in the dose of warfarin between the 3 genotypes within each race.
  
  
  CONCLUSIONS
  Our results suggest that C3435T polymorphism of MDR1 gene is not associated with warfarin resistance.
authors.affiliation: Department of Laboratory Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Yeongsic
authors.initials: Y
authors.lastname: Kim
authors.forename: Andrew
authors.initials: A
authors.lastname: Smith
authors.forename: Alan H B
authors.initials: AH
authors.lastname: Wu
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics*; D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000188:drug therapy / Q000208:ethnology / Q000235:genetics; D004334:Drug Administration Schedule; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D008297:Male; D008661:Metabolism, Inborn Errors; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D011655:Pulmonary Embolism / Q000188:drug therapy / Q000208:ethnology / Q000235:genetics; D044469:Racial Groups; D020246:Venous Thrombosis / Q000188:drug therapy / Q000208:ethnology / Q000235:genetics; D014859:Warfarin / Q000627:therapeutic use*
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000925:Anticoagulants; D014859:Warfarin
keywords: C3435T polymorphism; MDR1 gene; Warfarin resistance