title: A validation of the first genome-wide association study of calcaneus ultrasound parameters in the European Male Ageing Study.
abstract: BACKGROUND
  A number of single nucleotide polymorphisms (SNPs) have been associated with broadband ultrasound attenuation (BUA) and speed of sound (SOS) as measured by quantitative ultrasound (QUS) at the calcaneus in the Framingham 100K genome-wide association study (GWAS) but have not been validated in independent studies. The aim of this analysis was to determine if these SNPs are associated with QUS measurements assessed in a large independent population of European middle-aged and elderly men. The association between these SNPs and bone mineral density (BMD) measured using dual-energy X-ray absorptiometry (DXA) was also tested.
  
  
  METHODS
  Men aged 40-79 years (N = 2960) were recruited from population registers in seven European centres for participation in an observational study of male ageing, the European Male Ageing Study (EMAS). QUS at the calcaneus was measured in all subjects and blood was taken for genetic analysis. Lumbar spine (LS), femoral neck (FN) and total hip (TH) BMD were measured by DXA in a subsample of 620 men in two centres. SNPs associated with BUA or SOS in the Framingham study with p < 10-4 were selected and genotyped using SEQUENOM technology. Linear regression was used to test for the association between SNPs and standardised (SD) bone outcomes under an additive genetic model adjusting for centre. The same direction of effect and p < 0.05 indicated replication.
  
  
  RESULTS
  Thirty-four of 38 selected SNPs were successfully genotyped in 2377 men. Suggestive evidence of replication was observed for a single SNP, rs3754032, which was associated with a higher SOS (β(SD) = 0.07, p = 0.032) but not BUA (β(SD) = 0.02, p = 0.505) and is located in the 3'UTR of WDR77 (WD repeat domain 77) also known as androgen receptor cofactor p44. A single SNP, rs238358, was associated with BMD at the LS (β(SD) = -0.22, p = 0.014), FN (β(SD) = -0.31,p = 0.001) and TH (β(SD) = -0.36, p = 0.002) in a locus previously associated with LS BMD in large-scale GWAS, incorporating AKAP11 and RANKL.
  
  
  CONCLUSIONS
  We found suggestive evidence of association between a single SNP located in the 3'UTR of WDR77 with calcaneal ultrasound parameters. The majority of SNPs, associated with QUS parameters in the Framingham Study, were not replicated in an independent population sample of European men.
authors.affiliation: Arthritis Research UK Epidemiology Unit, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK.
authors.forename: Delnaz
authors.initials: D
authors.lastname: Roshandel
authors.forename: Wendy
authors.initials: W
authors.lastname: Thomson
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Pye
authors.forename: Steven
authors.initials: S
authors.lastname: Boonen
authors.forename: Herman
authors.initials: H
authors.lastname: Borghs
authors.forename: Dirk
authors.initials: D
authors.lastname: Vanderschueren
authors.forename: Ilpo T
authors.initials: IT
authors.lastname: Huhtaniemi
authors.forename: Judith E
authors.initials: JE
authors.lastname: Adams
authors.forename: Kate A
authors.initials: KA
authors.lastname: Ward
authors.forename: Gyorgy
authors.initials: G
authors.lastname: Bartfai
authors.forename: Felipe
authors.initials: F
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: Thang S
authors.initials: TS
authors.lastname: Han
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Kula
authors.forename: Michael E
authors.initials: ME
authors.lastname: Lean
authors.forename: Neil
authors.initials: N
authors.lastname: Pendleton
authors.forename: Margus
authors.initials: M
authors.lastname: Punab
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Silman
authors.forename: Frederick C
authors.initials: FC
authors.lastname: Wu
authors.forename: Kate L
authors.initials: KL
authors.lastname: Holliday
authors.forename: Terence W
authors.initials: TW
authors.lastname: O'Neill
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D000368:Aged; D000375:Aging / Q000235:genetics*; D002111:Calcaneus / Q000000981:diagnostic imaging*; D005060:Europe; D055106:Genome-Wide Association Study; D005838:Genotype; D006801:Humans; D015810:Linkage Disequilibrium / Q000235:genetics; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D014463:Ultrasonography