FRI0536 FAMILIAL MEDITERRANEAN FEVER (FMF): A SINGLE CENTEREXPERIENCE FROM TURKEY
Authors: Ayşe Tanatar, Şerife Gül Karadağ, Hafize Emine Sonmez, Mustafa Çakan, Nuray Aktay Ayaz
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> Familial Mediterranean fever (FMF) is the most common monogenic autoinflammatory disease mainly affecting ethnic groups living at Mediterranean region. Since the discovery of the <i>Mediterranean FeVer</i> (<i>MEFV</i>) gene, molecular genetic testing has been used as a diagnostic adjunct especially in atypical cases (1, 2). Although substantial progress had been achieved about the etiopathogenetic mechanisms of FMF during the past 20 years, the diagnosis is still based on clinical criteria. <h3>Objectives</h3> To define the demographic, clinical and laboratory characteristics of children with FMF and then to compare the identification capacity of 3 validated FMF diagnostic criteria (Tel-Hashomer, Livneh and Pediatric) at our cohort (3-5). <h3>Methods</h3> The medical records of 1685 children diagnosed and followed up as FMF were reviewed retrospectively. All patients were evaluated for three diagnostic criteria. <h3>Results</h3> A total of 1685 children (839 girls, 846 boys) were involved to the study. Family history of FMF was positive in 46.1%. The mean±standard deviation of current age, age at symptom onset, age at diagnosis were 13±5.4, 5.4±4.05, 7.9±4.1 years, respectively. Median (min-max) follow-up period was 3 (0.5-18) years. Among 1685 patients, 82.8% had fever, 78.2% had abdominal pain, 36.1% had arthritis, 22.6% had chest pain and 16.6% had erysipelas-like erythema. Three patients had biopsy proven amyloidosis. Concomitant disease was present in 140 (8.3%) patients. Most of them (40.7%) were diagnosed with juvenile idiopathic arthritis and FMF. Henoch-Schönlein vasculitis was observed in 35 (25%) patients. Median (min-max) PRAS score was 7 (3-13). Forty-four patients (2.6%) were unresponsive to adequate doses of colchicine. Among them, 16 (36.4%) were treated with anakinra and 28 (63.6%) received canakinumab. Children homozygous for <i>M694V</i> were found to have more severe course of disease and higher PRAS scores (p&lt;0.001). Furthermore, 34 (77.3%) of colchicine resistant patients carried at least one <i>M694V</i> variant. When we applied the diagnostic criteria to our cohort, 99.5% met the Livneh criteria, 91.6% fulfilled the pediatric criteria and 82.9% satisfied the Tel-Hashomer criteria. <h3>Conclusion</h3> This is the largest pediatric cohort studied and presented since now. We believe that the large number of our cohort is convincing at the point of discussing phenotype-genotype relations. We confirmed that carrying <i>M694V</i> mutation is associated with increased disease severity. On the other hand, we compared two adult and one pediatric validated diagnostic criteria at a largest group of children with FMF. <h3>References</h3> [1] Ancient missense mutations in a new member of the RoRet gene family are likely to cause familial Mediterranean fever. The International FMF Consortium (1997). Cell 90:797-807 [2] A candidate gene for familial Mediterranean fever (1997). Nat Genet 17:25-31. [3] Sohar E, Gafni J, Pras M, Heller H (1967) Familial Mediterranean fever. A survey of 470 cases and review of the literature. The American journal of medicine43:227-253 [4] Livneh A, Langevitz P, Zemer D, Zaks N, Kees S, Lidar T, Migdal A, Padeh S, Pras M (1997) Criteria for the diagnosis of familial Mediterranean fever. Arthritis and rheumatism40:1879-1885. [5] Yalcinkaya F, Ozen S, Ozcakar ZB, Aktay N, Cakar N, Duzova A, Kasapcopur O, Elhan AH, Doganay B, Ekim M, Kara N, Uncu N, Bakkaloglu A (2009) A new set of criteria for the diagnosis of familial Mediterranean fever in childhood. Rheumatology (Oxford, England) 48:395-398. <h3>Disclosure of Interests</h3> None declared