Diagnosis of familial Mediterranean fever following the initial presentation of monoarthritis.

Aims: To determine if familial Mediterranean fever (FMF) genetic testing should be advised in children with initial presentation of monoarthritis and to identify clinical parameters associated with FMF-induced arthritis that warrant genetic investigation.

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 that cause FMF syndrome were analyzed in the entire study population. Statistical analysis compared two groups according to FMF status (FMF arthritis and idiopathic arthritis).

Results: Among the cohort seven (10%) children harbored two 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 (six [86%] vs. 19 [30%], respectively) (P = 0.006, odds ration [OR] = 14.2). In addition, associated abdominal pain during the attack (two [28%] vs. two [3%], respectively) (P = 0.04, OR = 12.4) and a family history of FMF (two [29%] vs. five [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 a first episode of arthritis, without an identifying cause to strongly consider MEFV genetic testing of the common mutations in the relevant population.