title: Genetic variation in members of the leukotriene biosynthesis pathway confer an increased risk of ischemic stroke: a replication study in two independent populations.
abstract: OBJECTIVE
  The recent finding that genetic variants in 5-lipoxygenase activating protein and leukotriene A4 hydrolase may confer an increased risk of ischemic stroke has implicated the leukotriene family as potential mediators of cardiovascular disease. Using a case control replication methodology, all members of the leukotriene synthesis pathway and their receptors were examined for genetic variants, which may act as risk factors for all ischemic stroke and stroke subtypes.
  
  
  METHODS
  A case control methodology using a UK stroke cohort (872 cases, 933 controls) was adopted, with additional 5-lipoxygenase activating protein genotyping and replication of positive findings undertaken in an independent stroke population from Germany (601 cases, 736 controls).
  
  
  RESULTS
  Association was identified with variants in 5-lipoxygenase activating protein, leukotriene C4 synthase (leukotriene A4 hydrolase),and the leukotriene B4 receptor complex. Differing risks were identified for ischemic stroke subtypes. A variant in leukotriene C4 synthase was found to confer a 1.5-fold increase in risk of small vessel disease (RR, 1.515; 1.041 to 2.262; P=0.043) with replication in an independent cohort showing a similar risk (RR, 1.687; 1.065 to 2.675; P=0.026). A haplotype in the leukotriene B4 receptor complex was found to confer a 2.3-fold increase in risk of cardioembolic stroke (RR, 2.118; 1.194 to 3.760; P=0.01) and replication in a German cohort revealed a similar risk with a second distinct haplotype (RR, 2.060; 1.162 to 3.665; P=0.013).
  
  
  CONCLUSIONS
  Genetic variation in leukotriene pathway members and their receptors confer an increased risk of ischemic stroke in 2 independent populations. These risks show different magnitudes depending on ischemic stroke subtype.
authors.affiliation: Centre for Clinical Neuroscience, St Georges University of London, Cranmer Terrace, Tooting, London, SW17 0RE, UK. sbevan@sgul.ac.uk
authors.forename: Steve
authors.initials: S
authors.lastname: Bevan
authors.forename: Martin
authors.initials: M
authors.lastname: Dichgans
authors.forename: H Erich
authors.initials: HE
authors.lastname: Wiechmann
authors.forename: Andreas
authors.initials: A
authors.lastname: Gschwendtner
authors.forename: Thomas
authors.initials: T
authors.lastname: Meitinger
authors.forename: Hugh S
authors.initials: HS
authors.lastname: Markus
mesh_terms: D058927:5-Lipoxygenase-Activating Proteins; D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000453:epidemiology* / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D015331:Cohort Studies; D004851:Epoxide Hydrolases / Q000235:genetics* / Q000378:metabolism; D005260:Female; D020022:Genetic Predisposition to Disease / Q000453:epidemiology; D014644:Genetic Variation; D006239:Haplotypes; D006801:Humans; D015289:Leukotrienes / Q000096:biosynthesis; D008297:Male; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008875:Middle Aged; D018102:Receptors, Leukotriene B4 / Q000235:genetics* / Q000378:metabolism; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology* / Q000235:genetics; D006113:United Kingdom / Q000453:epidemiology
chemical_list: D058927:5-Lipoxygenase-Activating Proteins; C548592:ALOX5AP protein, human; D002352:Carrier Proteins; C513240:LTB4R protein, human; C485878:LTB4R2 protein, human; D015289:Leukotrienes; D008565:Membrane Proteins; D018102:Receptors, Leukotriene B4; D004851:Epoxide Hydrolases; C043134:leukotriene A4 hydrolase