The Frequency of Familial Mediterranean Fever Gene Mutations and the Correlations between Phenotype and Genotype in Turkish Children

Aim: Familial Mediterranian Fever is an autosomal recessive disease characterized by recurrent inflammatory attacks of serosal membranes. The aim of the current study was to determine the frequency of the Mediterranean fever (MEFV) gene pathogenic variants in 158 children (78 male, 80 female) diagnosed with Familial Mediterranean Fever (FMF) and to compare the phenotype-genotype correlation.

Methods: In our retrospective case-control study, 158 FMF patients (78 males, 80 females) who were diagnosed with MEFV gene mutation in Bursa Yuksek Ihtisas Training and Research Hospital, Department of Pediatrics between January 2018 and June 2019 were included in the study. Mutation screening of the MEFV gene was performed for 12 mutations and the 8 most common mutations were taken into the study.

Results: Abdominal pain (77.8%), fever (74%) and arthralgia (46.2%) were the most prevalent clinical features in our patients. The most frequent mutations were M694V, E148Q, V726A, M680I and P369S. In cases with M694 mutation, it was noted that the incidence of arthritis was 2.5 times, appendectomy frequency 3.1 times higher, and early diagnosis probability 3.2 times higher. The frequency of chest pain was 2.9 times higher in the M680I mutation, and the frequency of arthralgia was 2.2 times higher in the P369S mutation.

Conclusion: Patient’s mutations in FMF patients are important for clinical expectations, and some mutations such as P369S are not as innocent as expected. However, reevaluation of phenotypes of mutations that are rare with more patients will be significant.