Abstract
OBJECTIVES: A single nucleotide polymorphism (SNP) of the gene encoding protein tyrosine phosphatase type 22 (PTPN22 620W) has recently been described as a strong common genetic risk factor for human autoimmune disease. We have analysed the association of PTPN22 620W in patients with Behçet's disease (BD). METHODS: Genomic DNA was obtained from 270 patients with BD from the UK and the Middle East. Normal controls (n = 203) were collected from the same populations. Patients with idiopathic retinal vasculitis from the UK (n = 136) were used as disease controls. PTPN22 620W was detected by SSP-PCR analysis and agarose gel electrophoresis. RESULTS: The results showed an inverse correlation between the presence of PTPN22 620W and Behçet's disease in either patient group tested. There was a greatly reduced prevalence in Middle Eastern compared to UK patients and controls. Finally, there was no association with either UK patients with retinal vasculitis compared with UK controls. CONCLUSIONS: The presence of PTPN22 620W was inversely associated with BD and the distribution of the SNP in the Middle East supports previous findings in the global prevalence.