title: Association of specific haplotypes of neurotrophic tyrosine kinase receptor 2 gene (NTRK2) with vulnerability to nicotine dependence in African-Americans and European-Americans.
abstract: BACKGROUND
  The gene encoding neurotrophic tyrosine kinase receptor 2 (NTRK2) has been localized to a region on chromosome 9q22-q23 that showed a "suggestive" linkage to nicotine dependence (ND) in our previous linkage analyses. However, no association of NTRK2 with ND has been identified.
  
  
  METHODS
  Family-based association analyses of 2037 participants (1366 African Americans [AA], 671 European Americans [EA]) representing 602 nuclear families were performed to evaluate association of nine single nucleotide polymorphisms (SNPs) within NTRK2 with ND.
  
  
  RESULTS
  Individual SNP-based association analysis indicated that in the EA sample, SNPs rs1659400 and rs1187272 were significantly associated with at least one adjusted ND measure. Haplotype analysis revealed that even after Bonferroni correction, the haplotype T-T-A of rs1659400-rs1187272-rs1122530 had a highly significant positive association, with adjusted ND measures in the EA sample (max Z = 3.78; p = .0001, frequency 59.9%). We further identified a major haplotype, T-G-C-A-A (26%), formed by rs993315-rs736744-rs920776-rs4075274-rs729560, which showed a significant positive association (max Z = 2.97, p = .003) with adjusted ND measures in the AA sample.
  
  
  CONCLUSIONS
  These results strongly suggest that NTRK2 is a susceptibility gene for ND. These findings imply that NTRK2 plays a role in the etiology of ND and represents an important biological candidate for further investigation.
authors.affiliation: Department of Psychiatric Medicine, University of Virginia, Charlottesville, Virginia 22911, USA.
authors.forename: Joke
authors.initials: J
authors.lastname: Beuten
authors.forename: Jennie Z
authors.initials: JZ
authors.lastname: Ma
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Payne
authors.forename: Randolph T
authors.initials: RT
authors.lastname: Dupont
authors.forename: Xiang-Yang
authors.initials: XY
authors.lastname: Lou
authors.forename: Karen M
authors.initials: KM
authors.lastname: Crews
authors.forename: Robert C
authors.initials: RC
authors.lastname: Elston
authors.forename: Ming D
authors.initials: MD
authors.lastname: Li
mesh_terms: D000328:Adult; D001741:Black or African American; D002899:Chromosomes, Human, Pair 9; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D006239:Haplotypes; D006801:Humans; D015810:Linkage Disequilibrium; D008297:Male; D008875:Middle Aged; D009679:Nuclear Family; D020641:Polymorphism, Single Nucleotide; D020813:Receptor, trkB / Q000235:genetics*; D014029:Tobacco Use Disorder / Q000208:ethnology / Q000235:genetics*; D044465:White People
chemical_list: D020813:Receptor, trkB