Thoughts on the proposed links between Behçet's disease and familial Mediterranean fever.

© Copyright CLINICAL AND EXPERIMENTAL RHEUMATOLOGY 2002. Behçet’s syndrome (BS) is an inflammatory disorder characterized by recurrent oral aphtous ulcers, genital ulcers, uveitis and skin lesions (1, 2). Involvement of the central nervous system, gastrointestinal tract and large vessels is less frequent but may be life threateni n g. The disease is prevalent among Tu rk s , Jap a n e s e, Ko re a n s , I ra n i a n s , Saudi and non-Ashkenazi Jews and Moslems in Israel. Familial Mediterranean fever (FMF) is mainly inherited as an autosomal recessive condition. It is characterized by recurrent attacks of fever, and peritonitis, p l e u ri t i s , a rt h ri t i s , or ery s i p e l a s l i ke skin lesion (3, 4). The disease is common among Turks,Armenians, MiddleE a s t e rn Moslems and non-Ashke n a z i Jews. FMF and BS have some common clinical and genetic features. On the other hand there are also some features that a re uncommon. Table I summari ze s these findings. It is seen that the dissim i l a rities outnumber the similari t i e s . On the other hand there are enough clinical features that might cause a wrong diagnosis in either direction especially in a patient of a Mediterranean background. In 1997, Schwartz et al. reported that they found 39 patients with concurrent FMF and BD (5). While some of the patients had incomplete BS, 16 had the complete syndrome according to the International Study Group for Behçet’s Disease cri t e ria (6). Since these patients were recruited from a survey of 4000 FMF pat i e n t s , the re s e a rch e rs concluded that the concomitant occurrence of FMF and BD (1:250) was mu ch higher than expected in the ge n e ra l I s raeli population (7). Furt h e rm o re, t h ey suggested that BS should be i n cluded among other vasculitides common in FMF. Later, Birlik et al. described a case involving coexistence of FMF and BD and suggested that both disord e rs may have a common etiopathogenetic mechanism (8). Based upon the ab ove observat i o n , Fresco et al. tried to investigate the reverse association – i.e.: the prevalence of FMF among BS patients – reasoning that if the previous findings had been biological, then the reverse would also be true (9). In this study two control groups were used; one consisted of 82 Rheumatoid Arthritis (RA) patients and the second was comprised of 270 healthy individuals. The authors did not find a higher than expected number of FMF patients among 344 BS patients. The prevalence of FMF was similar among the RA patients cohort as well as among the healthy persons group. The same group also formally looked at this association in another study designed to reassess the validity of the International Study Group Criteria for BS (6). They found out that none of the 108 patients with FMF studied fulfilled the diagnostic criteria for BS (10). Recently, in a study by Ben-Chetrit et a l. the fre q u e n cy of BS among FMF patients and the reve rse association we re investigated. They found 2 BS patients among 355 FMF patients and 2 (same patients) FMF patients among 53 BS patients (11). Statistical analysis supported the findings that the association EDITORIAL Clinical and Experimental Rheumatology 2002; 20 (Suppl. 26): S1-S2.