Severe outcome of juvenile idiopathic arthritis (JIA) associated with familial Mediterranean fever (FMF).

Juvenile Idiopathic Arthritis (JIA) and Familial Mediterranean Fever (FMF) may involve the same population of children and be confused at times. In a cohort of 350 consecutive FMF patients followed by us, 98 had onset before 10 years of age and, of those, JIA was present in 3. All three had the M694 V mutation of the MEFV gene and were of North African ancestry. The prognosis of these 3 was extremely poor: one developed bilateral knee osteonecrosis with total joint replacement, repeated ileal obstruction with small bowel resection, renal failure and sterility due to amyloidosis and osteoporotic fractures and died at 42 years of age; a second developed deforming erosive arthropathy and underwent bilateral total hip replacement; the third developed severe erosive polyarthritis and also underwent bilateral hip replacements. Aggressive treatment is indicated when JIA and FMF coexist.