MEFV mutations and phenotype-genotype correlations in North African Jews and Armenians with familial Mediterranean fever.

BACKGROUND: Familial Mediterranean fever is a genetic disease in which some characteristic gene mutations have been found. OBJECTIVES: To analyze the phenotype-genotype correlations in North African Jews and Armenians with FMF. METHODS: We studied MEFV gene mutations and phenotype-genotype correlations in North African Jews and Armenians with Familial Mediterranean Fever living in France. RESULTS: M694V mutation was the most common mutation in Jews and in Armenians. Patients with M680I homozygosity or M680I/M694V compound heterozygosity had a phenotype as severe as patients with M694V homozygosity. CONCLUSIONS: This study characterizes the phenotype-genotype in specific ethnic groups of patients with FMF.

Mutations in the MEFV gene in a large series of patients with a clinical diagnosis of familial Mediterranean fever.

Familial Mediterranean fever (FMF) is an autosomal recessively inherited disease affecting patients of the Mediterranean basin. FMF is characterized by recurrent episodes of fever accompanied with topical signs of inflammation. Some patients can develop a renal amyloidosis associated (AA) amyloidosis. The administration of colchicine is an effective preventive treatment of both the attacks and amyloidosis. The FMF gene (MEFV) was cloned and missense mutations were found to be responsible for the disease. We investigated a large series of 303 unselected and unrelated patients of various ethnic backgrounds with a clinical suspicion of FMF to confirm or invalidate the diagnosis of FMF and to determine the spectrum of MEFV mutations. Molecular analysis focused on all the most frequent mutations identified so far, and an exhaustive analysis of exon 10, containing the mutational hotspot, was performed through DNA sequencing. Sixty-two percent of Sephardic, North African Arabs, Armenian and Turkish patients were either homozygous or compound heterozygous for MEFV mutations. In other populations surrounding the Mediterranean Sea such as Greek, Italian, Portuguese, Kurdish and Lebanese populations, mutations were also found. In general, patients without Mediterranean origin had no mutations in the MEFV gene. Two new mis-sense mutations were identified in exon 10 of the MEFV gene: the S675N in an Italian patient and the M680L in a French patient without any known at-risk ethnic ancestry.

Clinical versus genetic diagnosis of familial Mediterranean fever.

The diagnosis of familial Mediterranean fever (FMF) has until recently been based on clinical signs alone. Discovery of the MEFV gene has enabled a molecular approach to diagnosis, which is already well established for diagnosing typical clinical forms of FMF. We evaluated the utility of this molecular approach in a large series of patients with various clinical presentations and ethnic origins. We looked for mutations in the MEFV gene in 303 unselected consecutive patients with a variable (from high to low) clinical suspicion of FMF. Two mutations were found in 133 patients (44%). In 22 patients (7%), the clinical diagnosis of FMF was unlikely according to the Tel Hashomer clinical criteria. Our results suggest that the spectrum of FMF-associated signs is broader than previously believed. Wider indications for genotyping should lead to more frequent diagnosis of FMF.

MEFV-Gene analysis in armenian patients with Familial Mediterranean fever: diagnostic value and unfavorable renal prognosis of the M694V homozygous genotype-genetic and therapeutic implications.

Familial Mediterranean fever (FMF) is a recessively inherited disorder that is common in patients of Armenian ancestry. To date, its diagnosis, which can be made only retrospectively, is one of exclusion, based entirely on nonspecific clinical signs that result from serosal inflammation and that may lead to unnecessary surgery. Renal amyloidosis, prevented by colchicine, is the most severe complication of FMF, a disorder associated with mutations in the MEFV gene. To evaluate the diagnostic and prognostic value of MEFV-gene analysis, we investigated 90 Armenian FMF patients from 77 unrelated families that were not selected through genetic-linkage analysis. Eight mutations, one of which (R408Q) is new, were found to account for 93% of the 163 independent FMF alleles, with both FMF alleles identified in 89% of the patients. In several instances, family studies provided molecular evidence for pseudodominant transmission and incomplete penetrance of the disease phenotype. The M694V homozygous genotype was found to be associated with a higher prevalence of renal amyloidosis and arthritis, compared with other genotypes (P=.0002 and P=.006, respectively). The demonstration of both the diagnostic and prognostic value of MEFV analysis and particular modes of inheritance should lead to new ways for management of FMF-including genetic counseling and therapeutic decisions in affected families.

Colchicine concentration in leukocytes of patients with familial Mediterranean fever.

Free and total plasma, granulocyte and mononuclear cell colchicine concentrations were measured by radioimmunoassay in 30 patients with familial Mediterranean fever treated with colchicine 0.5 to 2 mg day-1. Colchicine concentrations showed a large intersubject variability in plasma (0.13-1.75 ng ml-1), granulocytes (4 to 64 ng/10(9) cells), and mononuclear cells (11.4 to 57.6 ng/10(9) cells). Whereas unbound and total plasma colchicine concentrations were well correlated, no correlation was found between total or free plasma and granulocyte or mononuclear cell colchicine concentrations and dose of administered colchicine. In contrast, total or free plasma and granulocyte or mononuclear cell colchicine concentrations were correlated using a hyperbolic function indicating saturable colchicine distribution in both leukocyte populations.

Colchicine disposition in human leukocytes after single and multiple oral administration.

Inasmuch as leukocytes were reported to be an active pharmacologic compartment, colchicine disposition was determined in plasma, granulocytes, and mononuclear cells in healthy volunteers after 1 mg oral single and multiple doses. After the single dose, maximal colchicine concentration was observed at 1 hour in plasma and 47 hours later in leukocytes. This delay was confirmed by the slow accumulation of colchicine by lymphocytes in culture. In the multiple-dose study, mean granulocyte colchicine concentration (20 to 53 ng/10(9) cells) were twofold higher than in mononuclear cells (9 to 24 ng/10(9) cells). Mean predicted colchicine multiple-dose granulocyte and mononuclear cell concentrations were 2.5-fold and ninefold higher, respectively, than those measured. After the last dose, colchicine decreased, with half-life values between 41 and 46 hours for leukocytes and 49 hours for plasma. This study validates leukocytes as a microcompartment whose kinetics correlates with colchicine biologic effects.

Increased procoagulant response of monocytes from patients with familial Mediterranean fever.

Familial Mediterranean Fever (FMF) is an inherited disease of unknown etiology characterized by recurrent inflammatory episodes. Circulating fibrin was found in patients with FMF in absence of clinical manifestation of thrombosis and was statistically less frequently observed in patients treated with colchicine. These results suggest a cellular dysfunction. Therefore, we examined the procoagulant activity (PCA) of isolated mononuclear leukocytes and purified monocytes from FMF patients (n = 20). No PCA was detectable on freshly-isolated monocytes. After several hours of culture. FMF monocytes contained more PCA than control cells and the difference was more marked after endotoxin stimulation. Data obtained with coagulation factor-deficient plasma and anti-human apoprotein III antiserum indicated that the enhanced PCA in FMF monocytes is thromboplastin-like. Lysozyme and interleukin 1 production by monocytes were similar in patients and controls. The increased monocyte PCA appears to be due to an intrinsic and selective higher responsiveness of monocytes.

Evidence for circulating fibrin in familial Mediterranean fever.

Cryofibrinogenemia was found in 10 of 24 plasma samples (42%) from subjects with FMF. This precipitate was found during active disease as well as during intervals between crises. We found a higher incidence of cryofibrinogenemia in subjects with mild to moderately severe disease not being treated with colchicine (six of eight) as compared with colchicine-treated subjects who were in partial or complete clinical remission (four or 16; p less than 0.02). All cryofibrinogen precipitates contained fibrin, as assessed by electrophoretic analyses showing the presence of multimeric crosslinked forms of fibrin(ogen) linked by gamma-dimers. This finding in clinical specimens supports the hypothesis that fibrin in an obligatory component of cryofibrinogen. Fibrin was also found in HPF (two of six specimens) prepared from cryofibrinogen-negative FMF plasmas, thus showing that soluble forms of fibrin are even more prevalent in this disorder than is indicated by the frequent finding of cryofibrinogenemia.

[Familial Mediterranean fever, complement, cryofibrinogen, colchicine (author's transl)]. / Complément sérique et cryofibrinogène dans la maladie périodique (fièvre méditerranéenne familiale).

The components C1, C4, C2, C3 of the complement system were measured in a group of 24 patients with Familial mediterranean fever (F.M.F.). The presence of cryofibrinogen and its analysis was performed in the same patient. C4, C2, C3, were increased in the F.M.F. group. Cryofibrinogenemia was found in 42 p. 100 of the patients. The cryofibrinogen was composed of fibrin, fibrinogen and plasma fibronectin. The cryofibrinogen was less frequent in the group of patients treated by colchicine (p less than 0.02).