This study reports three non-FMF pediatric patients with heterozygous MEFV mutations and an extraordinary arthritis as a recurrent idiopathic and intermittent (left and right) synovitis of hip (RSH), that is not typical for FMF arthritis and known rheumatic disease and discusses about FMF related arthritis and different rheumatic disease that has been affected by MEFV gene mutations. The gene discussed is MEFV; the disease is familial Mediterranean fever.