A multicase family with spondylarthropathies.

Thirty six members of a family with symptoms and signs from the skin and/or the joints were examined clinically and radiologically and HLA typed. Fourteen were classified as having inflammatory joint disease, eight of them with more than one disease within the spondylarthropathy group (SpA). Four had psoriasis of the skin, two of whom had psoriatic arthritis. Ten (five males, five females) had radiological signs of sacroiliitis, eight of them fulfilled the criteria for SpA. Five (four males, one female) with sacroiliitis had radiological signs of spine involvement. One female member was classified as having rheumatoid arthritis. Seven with sacroiliitis were HLA-B27 positive, related to the same haplotype. Two with psoriasis were B27 positive and the other two had another haplotype in common. No single HLA antigen or haplotype was associated with the inflammatory joint manifestations or skin lesions. This suggests involvement of other gene loci or coincidence of multicases.