title: Large-scale analysis of association between GDF5 and FRZB variants and osteoarthritis of the hip, knee, and hand.
abstract: OBJECTIVE
  GDF5 and FRZB have been proposed as genetic loci conferring susceptibility to osteoarthritis (OA); however, the results of several studies investigating the association of OA with the rs143383 polymorphism of the GDF5 gene or the rs7775 and rs288326 polymorphisms of the FRZB gene have been conflicting or inconclusive. To examine these associations, we performed a large-scale meta-analysis of individual-level data.
  
  
  METHODS
  Fourteen teams contributed data on polymorphisms and knee, hip, and hand OA. For rs143383, the total number of cases and controls, respectively, was 5,789 and 7,850 for hip OA, 5,085 and 8,135 for knee OA, and 4,040 and 4,792 for hand OA. For rs7775, the respective sample sizes were 4,352 and 10,843 for hip OA, 3,545 and 6,085 for knee OA, and 4,010 and 5,151 for hand OA, and for rs288326, they were 4,346 and 8,034 for hip OA, 3,595 and 6,106 for knee OA, and 3,982 and 5,152 for hand OA. For each individual study, sex-specific odds ratios (ORs) were calculated for each OA phenotype that had been investigated. The ORs for each phenotype were synthesized using both fixed-effects and random-effects models for allele-based effects, and also for haplotype effects for FRZB.
  
  
  RESULTS
  A significant random-effects summary OR for knee OA was demonstrated for rs143383 (1.15 [95% confidence interval 1.09-1.22]) (P=9.4x10(-7)), with no significant between-study heterogeneity. Estimates of effect sizes for hip and hand OA were similar, but a large between-study heterogeneity was observed, and statistical significance was borderline (for OA of the hip [P=0.016]) or absent (for OA of the hand [P=0.19]). Analyses for FRZB polymorphisms and haplotypes did not reveal any statistically significant signals, except for a borderline association of rs288326 with hip OA (P=0.019).
  
  
  CONCLUSIONS
  Evidence of an association between the GDF5 rs143383 polymorphism and OA is substantially strong, but the genetic effects are consistent across different populations only for knee OA. Findings of this collaborative analysis do not support the notion that FRZB rs7775 or rs288326 has any sizable genetic effect on OA phenotypes.
authors.affiliation: Department of Hygiene and Epidemiology, University of Ioannina School of Medicine, Ioannina, Greece.
authors.forename: Evangelos
authors.initials: E
authors.lastname: Evangelou
authors.forename: Kay
authors.initials: K
authors.lastname: Chapman
authors.forename: Ingrid
authors.initials: I
authors.lastname: Meulenbelt
authors.forename: Fotini B
authors.initials: FB
authors.lastname: Karassa
authors.forename: John
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authors.lastname: Loughlin
authors.forename: Andrew
authors.initials: A
authors.lastname: Carr
authors.forename: Michael
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authors.lastname: Doherty
authors.forename: Sally
authors.initials: S
authors.lastname: Doherty
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Gómez-Reino
authors.forename: Antonio
authors.initials: A
authors.lastname: Gonzalez
authors.forename: Bjarni V
authors.initials: BV
authors.lastname: Halldorsson
authors.forename: Valdimar B
authors.initials: VB
authors.lastname: Hauksson
authors.forename: Albert
authors.initials: A
authors.lastname: Hofman
authors.forename: Deborah J
authors.initials: DJ
authors.lastname: Hart
authors.forename: Shiro
authors.initials: S
authors.lastname: Ikegawa
authors.forename: Thorvaldur
authors.initials: T
authors.lastname: Ingvarsson
authors.forename: Qing
authors.initials: Q
authors.lastname: Jiang
authors.forename: Ingileif
authors.initials: I
authors.lastname: Jonsdottir
authors.forename: Helgi
authors.initials: H
authors.lastname: Jonsson
authors.forename: Hanneke J M
authors.initials: HJ
authors.lastname: Kerkhof
authors.forename: Margreet
authors.initials: M
authors.lastname: Kloppenburg
authors.forename: Nancy E
authors.initials: NE
authors.lastname: Lane
authors.forename: Jia
authors.initials: J
authors.lastname: Li
authors.forename: Rik J
authors.initials: RJ
authors.lastname: Lories
authors.forename: Joyce B J
authors.initials: JB
authors.lastname: van Meurs
authors.forename: Annu
authors.initials: A
authors.lastname: Näkki
authors.forename: Michael C
authors.initials: MC
authors.lastname: Nevitt
authors.forename: Julio
authors.initials: J
authors.lastname: Rodriguez-Lopez
authors.forename: Dongquan
authors.initials: D
authors.lastname: Shi
authors.forename: P Eline
authors.initials: PE
authors.lastname: Slagboom
authors.forename: Kari
authors.initials: K
authors.lastname: Stefansson
authors.forename: Aspasia
authors.initials: A
authors.lastname: Tsezou
authors.forename: Gillian A
authors.initials: GA
authors.lastname: Wallis
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Watson
authors.forename: Tim D
authors.initials: TD
authors.lastname: Spector
authors.forename: Andre G
authors.initials: AG
authors.lastname: Uitterlinden
authors.forename: Ana M
authors.initials: AM
authors.lastname: Valdes
authors.forename: John P A
authors.initials: JP
authors.lastname: Ioannidis
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001499:Bayes Theorem; D016022:Case-Control Studies; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006023:Glycoproteins / Q000235:genetics*; D055428:Growth Differentiation Factor 5 / Q000235:genetics*; D050823:Hand Joints; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000235:genetics*; D015207:Osteoarthritis, Hip / Q000235:genetics*; D020370:Osteoarthritis, Knee / Q000235:genetics*; D010641:Phenotype; D011110:Polymorphism, Genetic / Q000235:genetics*; D000099274:Frizzled-Related Proteins
chemical_list: D006023:Glycoproteins; D055428:Growth Differentiation Factor 5; D047908:Intracellular Signaling Peptides and Proteins; D000099274:Frizzled-Related Proteins; C525893:GDF5 protein, human