title: Activated protein C resistance in ischemic stroke not due to factor V arginine506-->glutamine mutation.
abstract: OBJECTIVE
  Resistance to activated protein C (APC), a natural plasma anticoagulant, is the most common identifiable risk factor for venous thromboembolic disease. One point mutation in coagulation factor V that renders it APC-resistant is found in >90% of APC-resistant venous thrombosis patients. To determine the prevalence of APC resistance and of this factor V mutation in stroke, we screened a group of ischemic stroke patients.
  
  
  METHODS
  Hispanic ischemic stroke patients were screened using two different activated partial thromboplastin time-based assays. One assay using neat patient plasma determined APC resistance, and the other assay using patient plasma diluted into factor V-deficient plasma determined APC-resistant factor V, including the Arg506-->Gln mutation. Results were compared with those in 31 Hispanic control subjects of similar ages.
  
  
  RESULTS
  Six of 63 (9.5%) stroke patients had APC resistance compared with none of 31 (0%) control subjects. No patient or control subject had APC-resistant factor V, ie, the factor V Arg506-->Gln mutation.
  
  
  CONCLUSIONS
  In Hispanic patients with ischemic stroke, the incidence (approximately 10%) of APC resistance is not caused by the factor V Arg506-->Gln mutation. APC resistance not caused by this factor V mutation may be a risk factor for ischemic stroke in this population.
authors.affiliation: Department of Neurology and Preventive Medicine, University of Southern California School of Medicine, Los Angeles 90033, USA.
authors.forename: M
authors.initials: M
authors.lastname: Fisher
authors.forename: J A
authors.initials: JA
authors.lastname: Fernandez
authors.forename: S F
authors.initials: SF
authors.lastname: Ameriso
authors.forename: D
authors.initials: D
authors.lastname: Xie
authors.forename: A
authors.initials: A
authors.lastname: Gruber
authors.forename: A
authors.initials: A
authors.lastname: Paganini-Hill
authors.forename: J H
authors.initials: JH
authors.lastname: Griffin
mesh_terms: D001120:Arginine / Q000235:genetics*; D001777:Blood Coagulation; D002545:Brain Ischemia / Q000097:blood*; D002352:Carrier Proteins / Q000097:blood* / Q000502:physiology; D002561:Cerebrovascular Disorders / Q000097:blood*; D005165:Factor V / Q000235:genetics* / Q000502:physiology; D005260:Female; D005973:Glutamine / Q000235:genetics*; D006630:Hispanic or Latino; D006801:Humans; D015141:Los Angeles; D008297:Male; D008875:Middle Aged; D010314:Partial Thromboplastin Time; D017354:Point Mutation / Q000235:genetics*; D015995:Prevalence; D012307:Risk Factors; D013923:Thromboembolism / Q000097:blood
chemical_list: D002352:Carrier Proteins; C020723:citrate-binding transport protein; D005973:Glutamine; D005165:Factor V; D001120:Arginine