title: Association of HTR2A polymorphisms with chronic widespread pain and the extent of musculoskeletal pain: results from two population-based cohorts.
abstract: OBJECTIVE
  The aim of the current study was to investigate whether genetic variation in genes across the serotoninergic system is associated with chronic widespread pain (CWP) and the number of pain sites reported.
  
  
  METHODS
  A discovery cohort, with pain data at 3 time points, was used to investigate genetic associations with 2 phenotypes: 1) CWP (at ≥ 2 time points; n = 164) compared with pain-free controls (at 3 time points; n = 172), and 2) the maximum number of pain sites reported at any 1 of the 3 time points (range of sites 0-29; n = 989). A cohort of 2,285 men for whom a DNA sample and pain data were available (including 203 CWP cases and 929 controls) was used for validation. Pairwise tagging (r(2) > 0.8) single-nucleotide polymorphisms (SNPs) were genotyped. Logistic and zero-inflated negative binomial regression analyses were used to test for SNP associations with CWP and the number of pain sites, respectively.
  
  
  RESULTS
  SNPs in HTR2A were associated with both pain phenotypes in the discovery cohort, and a number of these SNP associations were replicated in the validation cohort, some of which were attenuated after adjustment for depression. There was an increased likelihood of having CWP in subjects with 1 or 2 copies of the T allele of rs12584920 (odds ratio [OR] 1.64, 95% confidence interval [95% CI] 1.01-2.60 [P = 0.03] in the discovery cohort, and OR 1.46, 95% CI 1.07-2.00 [P = 0.018] in the validation cohort). A similar association was observed between rs17289394 and the maximum number of pain sites reported in both cohorts. Results from a meta-analysis of the data from the 2 cohorts further strengthened these findings.
  
  
  CONCLUSIONS
  The findings of this study support the role of HTR2A in the genetic predisposition to musculoskeletal pain.
authors.affiliation: University of Manchester, Manchester, UK.
authors.forename: Barbara I
authors.initials: BI
authors.lastname: Nicholl
authors.forename: Kate L
authors.initials: KL
authors.lastname: Holliday
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Macfarlane
authors.forename: Wendy
authors.initials: W
authors.lastname: Thomson
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Davies
authors.forename: Terence W
authors.initials: TW
authors.lastname: O'Neill
authors.forename: Gyorgy
authors.initials: G
authors.lastname: Bartfai
authors.forename: Steven
authors.initials: S
authors.lastname: Boonen
authors.forename: Felipe F
authors.initials: FF
authors.lastname: Casanueva
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Finn
authors.forename: Gianni
authors.initials: G
authors.lastname: Forti
authors.forename: Aleksander
authors.initials: A
authors.lastname: Giwercman
authors.forename: Ilpo T
authors.initials: IT
authors.lastname: Huhtaniemi
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Kula
authors.forename: Margus
authors.initials: M
authors.lastname: Punab
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Silman
authors.forename: Dirk
authors.initials: D
authors.lastname: Vanderschueren
authors.forename: Frederick C W
authors.initials: FC
authors.lastname: Wu
authors.forename: John
authors.initials: J
authors.lastname: McBeth
mesh_terms: D000328:Adult; D000368:Aged; D059350:Chronic Pain / Q000235:genetics*; D015331:Cohort Studies; D056726:Genetic Association Studies / Q000379:methods / Q000592:standards; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D059352:Musculoskeletal Pain / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D044402:Receptor, Serotonin, 5-HT2A / Q000235:genetics*; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics; D012720:Severity of Illness Index; D014365:Tryptophan Hydroxylase / Q000235:genetics
chemical_list: D044402:Receptor, Serotonin, 5-HT2A; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins; C494784:TPH2 protein, human; D014365:Tryptophan Hydroxylase