Does the age at disease onset cause a delay in diagnosis and affect disease severity in the children with familial Mediterranean fever?

Introduction Familial Mediterranean fever (FMF) is a systemic autoinflammatory disease characterized by recurrent attacks of fever and sterile peritonitis, pleuritis, arthritis or erysipelas-like erythema. Symptoms related with FMF can begin at very early ages of life. However, since most symptoms related to FMF are often well-known only when children become more verbal, and fever in children in the first years of life are common, attacks of fever alone may cause or contribute to diagnosis delay.