title: Phenotypic diversity is not determined by independent genetic factors in familial spondylarthropathy.
abstract: OBJECTIVE
  To analyze the segregation of manifestations belonging to the spectrum of spondylarthropathy (SpA) among patients and unaffected siblings within SpA multiplex families.
  
  
  METHODS
  Ninety-five multiplex families have been investigated. The diagnosis of SpA was made according to European Spondylarthropathy Study Group criteria. The prevalence of SpA manifestations was determined in unaffected siblings and compared with their prevalence in patients.
  
  
  RESULTS
  We compared 241 SpA patients with 259 unaffected siblings. The prevalence of skeletal and extraarticular features not used as diagnostic criteria, i.e., radiographic sacroiliitis, peripheral enthesitis, uveitis, psoriasis, and inflammatory bowel disease, was significantly increased in patients compared with unaffected siblings. This result was not accounted for by sex or HLA-B27 distribution differences.
  
  
  CONCLUSIONS
  In familial SpA, skeletal and extraarticular manifestations tend to segregate together, implying that all subsets are predominantly determined by a shared component, and that accessory factors must be responsible for phenotype diversity.
authors.affiliation: Cochin Hospital, AP-HP, Universite Rene Descartes, Paris, France.
authors.forename: R
authors.initials: R
authors.lastname: Said-Nahal
authors.forename: C
authors.initials: C
authors.lastname: Miceli-Richard
authors.forename: M A
authors.initials: MA
authors.lastname: D'Agostino
authors.forename: E
authors.initials: E
authors.lastname: Dernis-Labous
authors.forename: J M
authors.initials: JM
authors.lastname: Berthelot
authors.forename: A
authors.initials: A
authors.lastname: Duché
authors.forename: G
authors.initials: G
authors.lastname: Le Blévec
authors.forename: A
authors.initials: A
authors.lastname: Saraux
authors.forename: A
authors.initials: A
authors.lastname: Perdriger
authors.forename: S
authors.initials: S
authors.lastname: Guis
authors.forename: B
authors.initials: B
authors.lastname: Amor
authors.forename: M
authors.initials: M
authors.lastname: Dougados
authors.forename: M
authors.initials: M
authors.lastname: Breban
mesh_terms: D000328:Adult; D005260:Female; D014644:Genetic Variation; D015793:HLA-B7 Antigen / Q000097:blood; D006801:Humans; D008297:Male; D010641:Phenotype; D015995:Prevalence; D011565:Psoriasis / Q000453:epidemiology / Q000235:genetics; D011859:Radiography; D012737:Sex Factors; D025242:Spondylarthropathies / Q000097:blood / Q000000981:diagnostic imaging / Q000235:genetics*
chemical_list: D015793:HLA-B7 Antigen