Familial Mediterranean fever (FMF) in Turkey: results of a nationwide multicenter study.

https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(97)09408-7.pdf

Familial Mediterranean fever.

An emerging theme of studies with spontaneous, engineered and induced mutant mice is that phenotypes often depend on genetic background, implying that genetic modifiers have a role in guiding the functional consequences of genetic variation. Understanding the molecular and cellular basis by which modifier genes exert their influence will provide insights into developmental and physiological pathways that are critical to fundamental biological processes, as well as into novel targets for therapeutic interventions in human diseases.

Modifier genes in mice and humans.

Familial Mediterranean Fever (FMF) is the prototype of a group of inherited inflammatory disorders. The gene (MEFV) responsible for this disease, comprises 10 exons and 781 codons. Twenty-nine mutations, most located in the last exon, have been identified so far. It is unclear whether all are true disease-causing mutations. Five founder mutations, V726A, M694V, M694I, M680I and E148Q account for 74% of FMF chromosomes from typical cases (Armenians, Arabs, Jews, and Turks). Rare mutations are preferentially found in populations not usually affected by FMF (eg Europeans not from the above ancestries). The various combinations of MEFV mutations define severe to mild genotypes. The trend is that genotypes including two mutations located within mutational 'hot-spots' (codons 680 or 694) of the gene are associated with severe phenotypes, whereas mild phenotypes are associated with some other mutations, E148Q being the mildest and least penetrant. Understanding the correlation between the FMF phenotype and genotype is further obscured by the existence of complex alleles, modifier loci, genetic heterogeneity and possible epigenetic factors. Additionally, mutations in the MEFV gene are thought to be involved in non FMF disorders. Carrier rates for FMF mutations may be as high as 1:3 in some populations, suggesting that the disease is underdiagnosed. This review update emphasises that both clinical and genetic features are to be taken into account for patient diagnosis, colchicine treatment and prognosis.

/pdf/the-spectrum-of-familial-mediterranean-fever-fmf-mutations-27craxq6eg.pdf

The spectrum of Familial Mediterranean Fever (FMF) mutations.

Fever of undetermined origin may be familial and have a periodic course. This article discusses three syndromes of hereditary periodic fever: familial Mediterranean fever, the hyper-IgD syndrome, and the tumor necrosis factor receptor–associated periodic syndrome. Each is caused by mutations in different genes and affects different ethnic groups. Important recent advances in our understanding of the pathophysiology of these disorders are presented in this review article.

Hereditary Periodic Fever

Familial Mediterranean fever (FMF) is an autosomal recessive disease characterised by recurrent attacks of inflammation of serosal membranes. Amyloidosis is the most severe complication of the disease. The aim of this study was to investigate the genotype-phenotype correlation and specifically the association between amyloidosis and the four common mutations in exon 10 of the gene causing FMF (MEFV) in a total of 83 FMF families from three ethnic groups: North African Jews, Armenians and Turks. A significant association was found between amyloidosis and the specific mutation at the MEFV gene: Met694Val (RR = 1.41, P = 0.02). Amyloidosis was present in 18 out of 87 homozygous FMF patients (20.7%) and in only two out of the 41 compound heterozygous FMF patients (4.9%). No patients carrying other mutations had amyloidosis. There was no significant association between the various mutations and the type or severity of the FMF symptoms. This finding underscores the importance of performing molecular studies on all suspect FMF patients. In addition to providing accurate diagnosis, these tests allow identification of presymptomatic genetically affected individuals, detection of carriers and assessment of the risk for amyloidosis in later life.

/pdf/phenotype-genotype-correlation-in-familial-mediterranean-2944511otm.pdf

A Mimouni

Papers

Phenotype-genotype correlation in familial Mediterranean fever: evidence for an association between Met694Val and amyloidosis.