Investigation of association of the DLG5 gene with psoriatic arthritis.

摘要

Psoriatic arthritis (PsA) is defined as "an inflammatory arthritis associated with psoriasis which is usually negative for rheumatoid factor" and is the second most common cause of inflammatory joint disease after rheumatoid arthritis. A strong genetic component to disease aetiology has been shown, with the sibling recurrence risk (lambdas) estimated to be 27. Patients with Crohn's disease have an increased risk of developing both PsA and psoriasis. Crohn's disease and PsA are also both cytokine driven and both respond to anti-tumour necrosis factor a treatment. We therefore hypothesised that common genetic factors may underlie these two conditions. Indeed, the major Crohn's disease susceptibility gene, CARD15, has been reported to be associated with PsA in a Newfoundland population, and a second Crohn's disease susceptibility locus, the organic cation transporter gene cluster, has been associated with PsA in a UK population. Recently, DLG5, a membrane-associated guanylate kinase superfamily gene, has been identified as a further possible Crohn's disease genetic susceptibility factor. The protein is important in maintaining epithelial cell structure and transmitting extracellular signals to the cytoskeleton. The associated polymorphism (rsl248696) encodes a non-synonymous amino acid substitution (arginine->glutamme), which it was hypothesised, may affect the scaffolding function of the protein. The aim of this study was to investigate the association of DLG5 gene polymorphisms with susceptibility to PsA.