RESUMEN
Familial Mediterranean fever (FMF) is an autosomal recessive disease distributed among populations of Mediterranean origin - Armenians, Sephardi Jews, Arabs, Turks. There are numerous clinical observations regarding combination of FMF, as a classical representative of autoinflammatory diseases, with systemic diseases of connective tissue. Seronegative spondyloarthritis (SpA) are the most interesting disorders from this point of view, as far as sacroiliitis - an essential feature of SpA, may also present as a part of joint syndrome in FMF. The main objective of this clinical study was the investigation of the peculiarities of courses of FMF and SpA in case of their coexistence. We studied 126 patients with FMF, SpA and coexistence of both. According to results, patients with the overlap of FMF with SpA had relatively milder course of disease in comparison with each disease separately. Comparative clinical and instrumental characteristics of FMF-associated disorders had shown that in FMF-SpA overlap the symptoms of both diseases are less severe.