The spectrum of familial Mediterranean fever gene mutations in Arabs: report of a large series.

OBJECTIVES: To identify the frequency and distribution of familial Mediterranean fever (FMF) gene (MEFV) mutations in Arab patients.

PATIENTS AND METHODS: The study was performed in the pediatric FMF clinic of Jordan University Hospital over a period of 4 years. Patients were referred by their physicians for diagnosis, management, genetic study, and counseling. A diagnosis of FMF was made according to published criteria. Screening for 5 mutations, namely M694V, V726A, M694I, M680I, and E148Q, was performed by amplification refractory mutation system (ARMS) for the first 4 and by restriction endonuclease testing for E148Q.

RESULTS: Of the 407 unrelated patients investigated, 239 (59%) had 1 or 2 mutations and 168 (41%) had none of the studied mutations detected. Of those with mutations, 92 were homozygous, 53 were compound heterozygotes, 3 had complex alleles, and 91 patients had only 1 identifiable mutation. Of the mutations, M694V, V726A, M694I, M680I, and E148Q accounted for 38, 26, 14, 10 and 13%, respectively. Twelve of our patients developed the protracted febrile myalgia syndrome (PFMS) of whom 5 (42%) were homozygous for M694V. Only 2 developed chronic renal failure, both of whom were homozygous for M694V and were not on colchicine prophylaxis. However, 43 patients had a family history of chronic renal failure, and 15 (35%) were homozygous for M694V.

CONCLUSIONS: Our data indicate that the 5 MEFV mutations are well distributed in Arabs. They also show that M694V is the most common mutation in Arab patients with FMF and seems to have an association with the development of amyloidosis and the PFMS. The high frequency of V726A, and the unique high frequency of M694I in Arabs compared with 3 other ethnic groups, are confirmed.