THU0222 The Diagnosis of Familial Mediterranean Fever Following The Initial Presentation of Monoarthritis

Background Familial Mediterranean Fever (FMF) is the most common Mendelian autoinflammatory syndrome resulting from mutations in the MEFV gene [1]. Musculoskeletal involvement, mostly in the form of arthritis or arthralgia is the second common manifestation of FMF following periodic fever and abdominal pain [2,3]. The incidence and pattern of joint involvement is highly heterogeneous. Retrospective data suggest that arthritis may be the initial presentation of FMF in up to 15% of patients in certain populations [4,5].we aimed to examine whether certain “idiopathic monoarthritis” episodes are in fact the initial presentation of FMF. Objectives to prospectively investigate the prevalence of FMF in children admitted to our department with an acute episode of “idiopathic monoarthritis”. In addition we aimed to identify risk factors that when associated with monoarthritis, will specifically indicate genetic testing of the MEFV gene. Methods A prospective study of 71 otherwise healthy children admitted to our pediatric department between 2010–2013 with a first episode of idiopathic monoarthritis. Demographic, clinical and laboratory data were documented and genetic assay of the five common mutations in our population of the MEFV gene were analyzed in the entire study population. Results Among the cohort 7 (10%) children harbored 2 pathogenic mutations in the MEFV gene, thus confirming diagnosis of FMF. This FMF induced arthritis group had a statistically significant female predominance compared with the idiopathic arthritis group 6 (86%) vs 19 (30%), respectively) (P=0.006, OR =14.2). In addition, associated abdominal pain during the attack 2 (28%) vs 2 (3%), respectively (P=0.04, OR=12.4) and a family history of FMF 2 (29%) vs 5 (8%), respectively (P=0.1 OR 4.7,) were more common in the FMF induced arthritis group Conclusions In Mediterranean populations where FMF is relatively common we recommend for every child with first episode of arthritis, without an identifying cause to strongly consider MEFV genetic testing of the common mutations in the relevant population. References Barron K, Athreya B KD. Periodic Fever Syndromes and other inherited autoinflammatory diseases. Textb. Pediatr. Rheumatol., 2010, p. 642–60. Brik R, Shinawi M, Kasinetz L, Gershoni-Baruch R. The musculoskeletal manifestations of Familial Mediterranean fever in children genetically diagnosed with the disease. Arthritis Rheum 2001;44:1416–9. Inal A, Yilmaz M, Kendirli SG, Altintas DU, Karakoc GB. The clinical and genetical features of 124 children with Familial Mediterranean fever: Experience of a single tertiary center. Rheumatol Int 2009;29:1279–85. Ince E, Cakar N, Tekin M, Kendirli T, Ozkaya N, Akar N, et al. Arthritis in children with familial mediterranean fever. Rheumatol Int 2002;21:213–7. Lidar M, Kedem R, Mor A, Levartovsky D, Langevitz P, Livneh A. Arthritis as the sole episodic manifestation of familial Mediterranean fever. J Rheumatol 2005;32:859–62. Acknowledgement We wish to thank the patients and their families and to thank Mrs. Naama Schwartz for excellent statistical analysis. Disclosure of Interest None declared