Objective: To characterize the clinical and genetic features of familial Mediterranean fever (FMF).
Study design: Clinical presentation and MEditerranean FeVer mutation type of all patients with FMF, who first manifested the disease at < or =2 years of age were analyzed and compared with patients who first presented with FMF between 2 and 16 years.
Results: Of 814 patients with FMF, in 254 patients (31.2%) the first FMF attack was at < or =2 years of age, with a mean age at onset of 1.1 +/- 0.8 years. They were compared with 242 patients who presented with their first manifestation of FMF at 2 to 16 years. The clinical manifestations of FMF were comparable in the 2 patient groups, but the delay of diagnosis was longer in patients with early presentation (3.2 +/- 3.2 years vs.1.9 +/- 2.7 years in the group with onset at 2-16 years, P < .001). A subgroup of patients (60/254), who were diagnosed at < or =2 years had the highest rate of attacks of fever alone as their sole manifestation (40.0% vs 8.4%, P < .05), and less peritonitis (45% vs 86.1%, P < .05) and pleuritis (3.4% vs 32.9%, P < .05). Most of these patients were homozygous for the M694V mutation and were of North African (Sephardic Jewish) extraction.
Conclusion: In early life, FMF often begins with an atypical presentation, characterized by attacks of fever alone, and its diagnosis and initiation of treatment is therefore significantly delayed.
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