FAMILIAL AGGREGATION OF UNDIFFERENTIATED SPONDYLOARTHROPATHY ASSOCIATED WITH HLA-B7

Objective-To report multiple cases of recurrent seronegative arthropat hy, enthesopathy, or both, occurring in a single family in the absence of the HLA-B27 tissue type, coexistent psoriasis or inflammatory bowe l disease. Methods-Three generations of one family together with their general practitioners completed a standard questionnaire. All subject s with a positive questionnaire and two randomly chosen subjects with negative questionnaires were then examined by a single observer. HLA t issue typing and standard sacroiliac radiographs were performed. Resul ts-Seven of 12 family members with a positive questionnaire had early onset oligo- or polyarthritis, enthesitis, or both, and fulfilled esta blished criteria for spondyloarthropathy, although none had radiologic al evidence of sacroiliitis. The mean age at first symptom in this gro up was 22 years with only one individual having the first symptom over the age of 30 years. All subjects were rheumatoid factor negative. Hi stocompatibility studies showed a strong association with the HLA-B7 a ntigen. Conclusions-The observations provide further support for the e xistence of 'undifferentiated' spondyloarthropathy and suggest that th is can be associated with genetic factor other HLA-B27.