Familial Mediterranean fever and Behcet's disease - Are they associated?

Objective. To test whether the coexistence of familial Mediterranean fever (FMF) and Behcet's disease (BD) is more frequent than expected and whether each disease affects the severity of the other. Methods. We screened 353 charts of patients with FMF to detect individuals with concomitant BD. Of these, 152 patients with FMF over the age of 18 years were also interviewed and examined specifically. We also studied 53 patients with BD, looking for FMF and for their MEFV mutations. We compared BD patients with MEFV mutations to those without them. Results. None of 353 patients with FMF was found to have concomitant BD. Sixteen patients with BD bore MEFV mutations, 2 of whom were symptomatic homozygotes and had concomitant FMF. No patient with BD with a single MEFV mutation had FMF. Both BD groups (with or without MEFV mutations) were similar in their clinical manifestations and disease course. Conclusion. BD and FMF are 21 separate entities that have a mild trend toward a higher than expected association. However, there was no mutual effect of FMF an BD or vice versa.