The importance of Mediterranean fever gene in familial Mediterranean fever.

Abstract

Familial Mediterranean fever (FMF) is the most common autoinflammatory disease characterized by recurrent serositis attacks and fever. The discovery of the Mediterranean fever (MEFV) gene has been a milestone in FMF etiopathogenesis. Our knowledge about the relationship between the MEFV gene and FMF phenotype increases each day. This study aims to investigate the relationship between MEFV gene mutations and the FMF clinical findings of a single-center FMF cohort. Gender, age, age at symptom onset, age at diagnosis, clinical characteristics, and MEFV gene analysis of the patients were recorded. A total of 837 FMF patients were included in this study. There were 515 females and 322 males. The age at symptom onset was 18.3±10.9 years, while the age at diagnosis was 24.4±10.9 years. The most common symptom that accompanied fever was peritonitis (91.1%), while the other common clinical findings were pleuritis (45%), myalgia (44%), and arthritis (36%). A total of 47 patients developed amyloidosis. A total of 553 (66%) FMF patients had M694V mutation, 221 (26%) of which were homozygous, while 332 (40%) were heterozygous. Exon 10 mutation frequency was 759 (91%), while the non-exon 10 mutation frequency was 78 (9%). There was no wild type among the patients. In conclusion, the fact that a vast majority of the disease burden was constituted by the exon 10, especially M694V mutations and that none of the 837 patients from our cohort had a wild-type FMF proved the significance of MEFV gene mutation analysis. Therefore, we speculate that it is necessary to examine the MEFV gene mutations in each FMF suspected case. It seems plausible to re-evaluate the FMF diagnosis for cases in which a wild type MEFV gene mutation occurs.