MEFV mutation frequencies in a Turkish cohort with low prevalence of familial Mediterranean fever

Background/aimFamilial Mediterranean fever (FMF) is a genetically recessive autoinflammatory disease caused by mutations in the Mediterranean fever (MEFV) gene. The aim of this study was to investigate the frequencies of the most common MEFV mutations among a sample of healthy individuals from the Havsa population of European Turkey, where FMF is less prevalent compared to Asian Turkey.Materials and methodsThe study group consisted of 263 unrelated healthy adults. All of the participants were analyzed for the M694V, V726A, M680I, and E148Q mutations in the MEFV gene.ResultsIn total, 25 of the 263 individuals carried MEFV mutations (9.5%). The observed allele frequencies were 1.5% for M694V (95% confidence interval [CI] 0.5-2.5), 2.6% for E148Q (95% CI 1.6-3.9), 0.5% for M680I (95% CI 0.0-1.1), and 0.0% for V726A. The frequencies of the M694V, M680I, and E148Q mutations were not significantly different from allele frequencies (approximately 20%) determined for other regions of Turkey where FMF is more prevalent.ConclusionThese data suggest that the positivity of the MEFV gene mutation tests have lower predictive value in a population with low FMF prevalence.     

The Population Genetics of Familial Mediterranean Fever: A Meta‐Analysis Study

Our aim was to construct a Familial Mediterranean Fever (FMF) cumulative database and to propose a MEFV based phylogenetic tree. Data were collected from published studies. A meta‐analysis based on 16,756 chromosomes from FMF patients and normal individuals from 14 affected populations was performed. Arlequin 2.0 and Phylip 3.2 software were used for population genetics analysis and phylogenetic tree construction. We have shown that MEFV mutations are distributed non‐uniformly along the Mediterranean Sea area. The most frequent mutations detected in FMF patients are M694V (39.6%), V726A (13.9%), M680I (11.4%), E148Q (3.4%), and M694I (2.9%), while 28.8% of chromosomes carry unidentified or no mutations, especially in Western Europeans. The mean overall carrier rate is 0.186 with peak values in Arabs, Armenians, Jews, and Turks. Only V726A obeys the Hardy‐Weinberg law in FMF patients implying that this mutation is the most ancient. Jews present the most intense genetic isolation and drift; thus they might have nested de novo mutations and accelerated evolution. Besides Jews, three population groups might follow distinct evolutionary lines (Asia Minor, Eastern European, and Western European). In conclusion, the MEFV mutation pattern is non‐uniform regarding distribution, phenotypic expression, neutrality and population genetics characteristics. Jews are the candidate population for founder effects in MEFV.     

The M694I/M694I genotype: A genetic risk factor of AA-amyloidosis in a group of Algerian patients with familial Mediterranean fever

Familial Mediterranean fever (FMF, OMIM 249100) is the most common hereditary fever, resulting from mutations in MEFV. FMF is characterized by episodic febrile attacks and polyserositis. Renal AA-amyloidosis is a major complication, which often leads to end-stage renal disease in untreated patients. The data about the renal AA-amyloidosis secondary to FMF are scarce in North African countries and non-existent in Algeria. We aimed to investigate the MEFV mutations associated with this complication in an Algerian patient cohort. Molecular analysis included 28 unrelated Algerian FMF patients with ascertained amyloidosis, 23 of them were symptomatic and 5 were asymptomatic. For this study, a group of 20 FMF patients without renal amyloidosis were selected as controls according to their age, disease onset and disease duration. The mutations were detected by sequencing exon 10 of MEFV. A total of 87.5% (49/56) mutant alleles were identified in 27/28 analyzed patients; p.M694I was predominant and appeared with an allele frequency of 62.5%, followed by p.M694V (17.85%), p.M680I (5.35%) and p.I692Del (1.78%). Remarkably, only p.M694I mutation was observed among the asymptomatic patients. The M694I/M694I genotype, identified in 14/27 (52%) patients, was significantly associated with the development of amyloidosis compared to group of controls (p = 0.022). This study did not link the M694V/M694V genotype to the renal complication despite the fact that it has been observed only in the patients with amyloidosis (3/27; 11%) (p = 0.349). The association of other identified genotypes to this complication was statistically insignificant. The progression of amyloidosis led to end-stage renal disease in 14 patients with 6 deaths. This study shows that p.M694I homozygosity is a potential genetic risk factor for the development of renal AA-amyloidosis in Algerian FMF patients.