Common Crohn's disease-predisposing variants of the CARD15/NOD2 gene are not associated with Behçet's disease in Turkey.

OBJECTIVE There are many extra-intestinal findings of Crohn's disease (CD), such as oral and genital ulcers, erythema nodosum, uveitis and arthritis, resembling the manifestations of Behçet's disease (BD). It is also very difficult to distinguish the gastrointestinal involvement of BD from that of CD in some patients. Hence, this study aimed to investigate a possible involvement of the common CD-predisposing CARD15 variants in the genetic susceptibility to BD. METHODS The study group consisted of 85 consecutive patients with BD (51 male, 34 female) of Turkish origin. Two of them had intestinal involvement. A group of 100 ethnically matched, non-related healthy volunteers were used as controls. All individuals were genotyped for 3 common CARD15 variants (R702W, G908R, and Ll007fsinsC) using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. RESULTS None of the three CARD15 variants predisposing to CD was observed in patients with BD, including two patients with intestinal involvement. The R702W mutation was observed in I healthy chromosome, and the 3020insC mutation in 2 chromosomes. No individual was found to be homozygous or compound heterozygous for these variants. CONCLUSION These findings suggest that 3 most common CD-predisposing CARD15 variants do not constitute a genetic susceptibility factor for BD in Turkey. Further studies would be helpful to rule out a possible contribution of other rare or unknown variants and/or the effects of different ethnic backgrounds.