title: The genetic influence on radiographic osteoarthritis is site specific at the hand, hip and knee.
abstract: OBJECTIVE
  To identify whether a shared genetic influence accounts for the occurrence of OA at different skeletal sites.
  
  
  METHODS
  Multivariate modelling of data on prevalent radiographic OA at the hand (DIP, PIP and CMC joints), hip and knee joints assessed in 992 monozygotic and dizygotic female twin participants from the TwinsUK Registry.
  
  
  RESULTS
  OA at all the five joint sites was heritable. Genetic influences were strongly correlated among joints in the hand; however, there was little evidence of common genetic pathways to account for the co-occurrence of OA at the hand, hip and knee.
  
  
  CONCLUSIONS
  While genetic influences are important in explaining the variation in occurrence of OA at the hand, hip and knee, there is no evidence that common or shared genetic factors determine the occurrence of disease across all these skeletal sites. The findings suggest that there are important aetiological differences in the disease that are site-specific in women. These results have implications for the design of studies examining the genetic basis of OA as well as for strategies aimed at preventing and treating the disease.
authors.affiliation: School of Medicine, University of East Anglia, Norwich NR4 7TJ, UK. a.macgregor@uea.ac.uk
authors.forename: A J
authors.initials: AJ
authors.lastname: MacGregor
authors.forename: Q
authors.initials: Q
authors.lastname: Li
authors.forename: T D
authors.initials: TD
authors.lastname: Spector
authors.forename: F M K
authors.initials: FM
authors.lastname: Williams
mesh_terms: D000328:Adult; D000368:Aged; D004200:Diseases in Twins / Q000000981:diagnostic imaging / Q000235:genetics*; D005260:Female; D008040:Genetic Linkage; D020022:Genetic Predisposition to Disease; D050823:Hand Joints / Q000000981:diagnostic imaging; D006801:Humans; D008875:Middle Aged; D010003:Osteoarthritis / Q000000981:diagnostic imaging / Q000235:genetics* / Q000473:pathology; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging / Q000235:genetics; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000235:genetics; D010641:Phenotype; D011859:Radiography; D014429:Twins, Dizygotic / Q000235:genetics; D014430:Twins, Monozygotic / Q000235:genetics; D055815:Young Adult