title: Familial aggregation of undifferentiated spondyloarthropathy associated with HLA-B7.
abstract: OBJECTIVE
  To report multiple cases of recurrent seronegative arthropathy, enthesopathy, or both, occurring in a single family in the absence of the HLA-B27 tissue type, coexistent psoriasis or inflammatory bowel disease.
  
  
  METHODS
  Three generations of one family together with their general practitioners completed a standard questionnaire. All subjects with a positive questionnaire and two randomly chosen subjects with negative questionnaires were then examined by a single observer. HLA tissue typing and standard sacroiliac radiographs were performed.
  
  
  RESULTS
  Seven of 12 family members with a positive questionnaire had early onset oligo- or polyarthritis, enthesitis, or both, and fulfilled established criteria for spondyloarthropathy, although none had radiological evidence of sacroiliitis. The mean age at first symptom in this group was 22 years with only one individual having the first symptom over the age of 30 years. All subjects were rheumatoid factor negative. Histocompatibility studies showed a strong association with the HLA-B7 antigen.
  
  
  CONCLUSIONS
  The observations provide further support for the existence of 'undifferentiated' spondyloarthropathy and suggest that this can be associated with genetic factors other than HLA-B27.
authors.affiliation: Inflammation Research Group, London Hospital Medical College, United Kingdom.
authors.forename: B L
authors.initials: BL
authors.lastname: Kidd
authors.forename: P J
authors.initials: PJ
authors.lastname: Wilson
authors.forename: P R
authors.initials: PR
authors.lastname: Evans
authors.forename: M I
authors.initials: MI
authors.lastname: Cawley
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D005260:Female; D015793:HLA-B7 Antigen; D006239:Haplotypes; D006801:Humans; D007592:Joint Diseases / Q000235:genetics* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D013122:Spinal Diseases / Q000235:genetics* / Q000276:immunology; D013585:Synovitis / Q000235:genetics / Q000276:immunology
chemical_list: D015793:HLA-B7 Antigen