AB1161 Familial mediterranean fever as an outcome of undifferentiated arthritis
Authors: V. Vardanyan, K. Ginosyan, A. Simonyan, S. Bakhshyan
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> The term «undifferentiated arthritis» (UA) was proposed to emphasise the heterogeneity of unclassifiable arthritides and their potential into a definable form of arthritis. A patient with UA have an early stage of defined arthritis that will meet criteria in time, a forme fruste or partial form of a classifiable disease, an overlap of more than one disease entity, or an arthritis of unknown or in that may (or may not) become differentiated in the future. The heterogeneity associated with the term «UA» emphasises the need for continued follow-up and reassessment of the diagnosis and management of these patients. <h3>Objectives</h3> The aim of this study was revelation of MEFV gene mutations in patients with UA. <h3>Methods</h3> We have examined 80 patients (34 male, 46 female, mean age 36,4±3.4 years) with UA. The patients were observed every 6 months in follow-up period of 5 years. The anamnestic and treatment data were obtained. Joint disease activity scores and presence of extra-articular manifestations were determined. The CBC, urinalysis, serum concentrations of creatinine, bilirubin, transaminases, glucose, CRP were determined every 6 months, X-ray examination and ultrasonography of joints were performed once a year. Molecular-genetic analysis of 12 MEFV-mutations, common for Armenians, were carried out in Medical Genetic Centre of Armenia. <h3>Results</h3> From 80 investigated patients with UA 10 had repeated episodes of mono- and oligoarthritis of ankle and/or knee joints with local skin hyperemia and hyperthermia, without subsequent joint deformities, 45 – sacroiliitis (26 bilateral, 19 unirateral), accompanied by enthesopathy, 2 – joint syndrome, resembling rheumatoid arthritis. In 23 patients joint syndrome was accompanied by erythema rash, livedo reticularis, photosensitivity and alopecia. The latter group of patients was diagnosed as SLE-like syndrome. All patients didn't fulfil accepted classification criteria of any autoimmune or autoinflammatory disease. The 80% of investigated patients had no classic febrile attacks of abdominalgia and/or thoracalgia, specific for FMF. In remaining 20% of patients febrile attacks hadn't preceded joint syndrome, but appeared during 5 year follow-up period. All investigated patients had MEFV gene mutations, which's compositions (homozygous or compound heterozygous) were enough to confirm Familial Mediterranean Fever (FMF). The most common mutations were: M694V–41.2%, V726A-18.8%, M680I-10%. The most common compositions were M694V/M694V, M694V/V726A, M694V/M680I. <h3>Conclusions</h3> As FMF is widely distributed in Mediterranean region, and it had changed its phenotype in last decades, as well as taking into account the increasing rate of migration worldwide, every single case of UA, which doesn't fulfil classification criteria of any disease, should be tested for presence of MEFV-mutations. The diagnosis of FMF changes the approach to follow-up, management, outcome and prognosis of UA. <h3>Disclosure of Interest</h3> None declared