Phenotype-genotype correlation in Jewish patients suffering from familial Mediterranean fever (FMF).

Familial Mediterranean Fever is one of the most frequent recessive disease in non-Ashkenazi Jews. The gene responsible for the disease (MEFV) has very recently been identified. The M694V ('MED') mutation was found in about 80% of the FMF Jewish (Iraqi and North African) chromosomes. To see if the presence of this mutation could be correlated with particular traits of the disease, we examined a number of clinical features in a panel of 109 Jewish FMF patients with 0, 1 or 2 MED mutations. We showed that homozygosity for this mutation was significantly associated with a more severe form of the disease. In homozygous patients, the disease started earlier (mean age 6.4 +/- 5 vs 13.6 +/- 8.9) and both arthritis and pleuritis were twice as frequent as in patients with one or no M694V mutation. Moreover, 3/3 patients with amyloidosis displayed two MED mutations. No association was found with fever, peritonitis, response to colchicine and erysipeloid eruption. The present result strongly suggests the potential prognostic value of the presence of this mutation.

Non-founder mutations in the MEFV gene establish this gene as the cause of familial Mediterranean fever (FMF).

Familial Mediterranean fever (FMF) is an autosomal recessive disorder characterized by recurring attacks of fever and serositis. It affects primarily North African Jews, Armenians, Turks and Arabs, in which a founder effect has been demonstrated. The marenostrin-pyrin-encoding gene has been proposed as a candidate gene for the disease ( MEFV ), on the basis of the identification of putative mutations clustered in exon 10 (M680V, M694I, M694V and V726A), each segregating with one ancestral haplotype. In a search for additional MEFV mutations in 120 apparently non-founder FMF chromosomes, we observed eight novel mutations in exon 2 (E148Q, E167D and T267I), exon 5 (F479L) and exon 10 (I692del K695R, A744S and R761H). Except for E148Q and K695R, all mutations were found in a single chromosome. Mutation E148Q was found in all ethnic groups studied and in association with a novel ancestral haplotype in non-Ashkenazi Jews (S2). Altogether, these new findings definitively establish the marenostrin/pyrin-encoding gene as the MEFV locus.

Familial Mediterranean fever clinical and genetic features in Druzes and in Iraqi Jews: a preliminary study.

OBJECTIVE: A number of differences have been noted in clinical familial Mediterranean fever (FMF) among ethnic groups. Iraqi Jews and Druzes are characterized by less severe disease. The differences in disease expression raise the possibility of background genes peculiar to specific ethnic groups. METHODS: We analyzed a series of FMF linked microsatellite markers and searched for gene mutations in these 2 populations. RESULTS: We observed a conserved haplotype in 46% of the FMF druze chromosomes that was different from the Mediterranean haplotype but identical to the ARM3 haplotype. In contrast, 56% of the FMF chromosomes in Iraqi Jews displayed the same mutation as that found in Jews from North Africa. CONCLUSION: Variable expression in FMF is probably due to both allelic heterogeneity and/or modifier genes as well as environmental factors.

Genotypic diagnosis of familial Mediterranean fever (FMF) using new microsatellite markers: example of two extensive non-Ashkenazi Jewish pedigrees.

Familial Mediterranean fever is an autosomal recessive disease characterised by multiple attacks of serosal inflammation in the absence of treatment. In the absence of timely diagnosis, renal amyloidosis is a life threatening complication. The diagnosis is often missed because no specific test is available. Early colchicine treatment prevents attacks and renal complications. The FMF gene (MEF) has been mapped to chromosome 16p 13.3 but has not yet been identified. We compared the suitability of a series of microsatellite markers (four of them were new) and propose the routine use of seven of these markers, exhibiting alleles in strong linkage disequilibrium with the disease and informative in 100% of diagnosed patients. Moreover, the discovery of a homozygous status for the 3-3-9 (or 3-3-18) haplotype at the core loci (D16S3070, D16S3082, and D16S3275), which was found in 73% non-Ashkenazi Jewish patients, points to a diagnosis of FMF, even in sporadic cases, with a risk of error of only 2.10(-5). Two extensive pedigrees covering most indications for genetic counselling are presented, showing that it is now possible both prospectively and retrospectively to identify members likely to have MEF mutations. With the help of this accurate test, colchicine treatment can be better targeted, especially where the symptomatology is mild or atypical.