Isabelle Touitou

A candidate gene for familial Mediterranean fever

Familial Mediterranean fever (FMF) is an autosomal recessive disorder characterized by attacks of fever and serositis. In this paper, we define a minimal co-segregating region of 60 kb containing the FMF gene (MEFV) and identify four different transcript units within this region. One of these transcripts encodes a new protein (marenostrin) related to the ret-finger protein and to butyrophilin. Four conservative missense variations co-segregating with FMF have been found within the MEFV candidate gene in 85% of the carrier chromosomes. These variations, which cluster at the carboxy terminal domain of the protein, were not present in 308 control chromosomes, including 162 validated non-carriers. We therefore propose that the sequence alterations in the marenostrin protein are responsible for the FMF disease.

The spectrum of Familial Mediterranean Fever (FMF) mutations

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.

Treatment of autoinflammatory diseases: results from the Eurofever Registry and a literature review

Objective To evaluate the response to treatment of autoinflammatory diseases from an international registry and an up-to-date literature review. Methods The response to treatment was studied in a web-based registry in which clinical information on anonymised patients with autoinflammatory diseases was collected retrospectively as part of the Eurofever initiative. Participating hospitals included paediatric rheumatology centres of the Paediatric Rheumatology International Trial Organisation network and adult centres with a specific interest in autoinflammatory diseases. The following diseases were included: familial Mediterranean fever (FMF), cryopyrin-associated periodic syndromes (CAPS), tumour necrosis factor (TNF)-receptor associated periodic syndrome (TRAPS), mevalonate kinase deficiency (MKD), pyogenic arthritis pustulosis acne (PAPA) syndrome, deficiency of interleukin-1 receptor antagonist (DIRA), NLRP12-related periodic fever and periodic fever aphthosis pharyngitis adenitis (PFAPA) syndrome. Cases were independently validated by experts for each disease. A literature search regarding treatment of the abovementioned diseases was also performed using Medline and Embase. Results 22 months from the beginning of the enrolment, complete information on 496 validated patients was available. Data from the registry in combination with evidence from the literature confirmed that colchicine is the treatment of choice for FMF and IL-1 blockade for DIRA and CAPS. Corticosteroids on demand probably represent a valid therapeutic strategy for PFAPA, but also for MKD and TRAPS. Patients with poorly controlled MKD, TRAPS, PAPA or FMF may benefit from IL-1 blockade; anti-TNF treatment may represent a possible valuable alternative. Conclusions In the absence of high-grade evidence, these results could serve as a basis for therapeutic guidelines and to identify candidate drugs for future therapeutic trials.

The infevers autoinflammatory mutation online registry: update with new genes and functions.

Infevers (Internet Fevers; http://fmf.igh.cnrs.fr/ISSAID/infevers), a website dedicated to mutations responsible for hereditary autoinflammatory diseases, was created in 2002 and has continued to evolve. This new version includes eight genes; six were already present: MEFV, MVK, TNFRSF1A, NLRP3, NOD2, PSTPIP1, and two are new, LPIN2 and NLRP7. Currently, Infevers contains over 540 sequence variants. Several new database functions were recently instituted. The website now accepts confidential data and complex alleles. For each gene, a newly created menu offers: 1) a tabular list of the variants that can be sorted by several parameters; 2) a gene graph providing a schematic representation of the variants along the gene; 3) statistical analysis of the data according to the phenotype, alteration type, and location of the mutation in the gene; 4) the cDNA and gDNA sequences of each gene, showing the nucleotide changes along the sequence, with a color‐based code highlighting the gene domains, the first ATG, and the termination codon; and 5) a “download” menu making all tables and figures available for the users, which, except for the gene graphs, are all automatically generated and updated upon submission of the variants. Finally, the entire database was curated to comply with the HUGO Gene Nomenclature Committee (HGNC) and HGVS nomenclature guidelines, and wherever necessary, an informative note was provided. Infevers has already proven useful for the scientific community with a mean number of visits per month of 200 in 2002 and 800 in 2007, and its new design will lead to a more comprehensive comparative analysis and interpretation of auto‐inflammatory sequence variants. Hum Mutat 29(6), 803–808, 2008. Published 2008, Wiley‐Liss, Inc.

Familial Mediterranean Fever in the World

Introduction Familial Mediterranean fever (FMF) is an autosomal recessive disease characterized by recurrent episodes of fever accompanied by peritonitis, pleuritis, arthritis, or erysipelas-like erythema (1,2). A typical FMF attack lasts approximately 3 days. The frequency of episodes varies from once every week to several times a year. One of the devastating complications of FMF is the development of serum amyloid A (SAA) amyloidosis, which mainly affects the kidneys but may involve other organs. Since 1972, colchicine has been the treatment of choice for FMF (3). It controls the acute attacks and prevents the development of amyloidosis. The disease is prevalent among populations surrounding the Mediterranean Sea. However, in recent years, more and more cases have been reported in countries not related or close to this area, such as the US and Japan. This observation raised the question as to the real prevalence of FMF in countries other than those around the Mediterranean basin and to its clinical characteristics in these countries. Furthermore, it poses a challenge to find out the ethnic origin of these patients and to study whether their disease behaves similarly to that in the countries commonly associated with FMF. FMF may display a different clinical picture among various populations, and these differences reflect the change in the repertoire of mutations among the specific populations. In this review, we will try to look for and explain the origin of FMF in countries far from the Mediterranean and Middle East regions. We will also compare the nature of the disease in these countries and find out whether they differ from the FMF manifestations, treatment, and prognosis in patients surrounding the Mediterranean Sea. Prevalence of FMF in the world FMF is almost always restricted to Turks, Armenians, Arabs, and non-Ashkenazi Jews. It is quite a rare disease in the rest of the world, although patients with FMF have been reported in European countries such as France, Germany, Italy, and Spain, as well as in the US and Australia (2,4). The exact frequency of FMF among the various populations is not always available because formal epidemiologic studies have not been done. Nevertheless, a rough estimate regarding the prevalence of the disease can be obtained by gathering details from different studies and sources (Figure 1). Turkey is probably the country with the highest number of FMF patients in the world. Since the prevalence of FMF is approximately 1:400 to 1:1,000 (highest in the areas of Anatolia) and the population is approximately 70 million, it is estimated that Turkey has more than 100,000 patients with FMF (4–6). In Israel, the prevalence is slightly more than 1:1,000 (depending on the ethnic group), and since the population is approximately 7 million, it is estimated that there are approximately 10,000 patients (7). Armenia is probably the next country with widespread FMF. It is estimated that the prevalence of FMF is approximately 1:500 and with a population of 3 million, the total number of patients is approximately 6,000 (8). Other countries in the Middle East such as Jordan, Syria, and Lebanon have many FMF patients, but their exact number is not known (9,10). In addition to the above countries, FMF is found in significant numbers in North African countries, Greece, Crete, France, Germany, Italy, and the US (11–14). In recent years, approximately 100 cases have been reported in Japan (15, 16, and Tsuchiya-Suzuki A, et al: unpublished observations). On the other hand, there are countries where FMF has not been found or reported. These include sub-Saharan African countries, Ethiopia, Yemen, and Scandinavian states, as well as South Asian and Far Eastern countries such as India and Thailand. The identification of the MEFV gene associated with FMF and the prevalence of its mutations in the different ethnic groups allowed some hypotheses on the phylogeny of the disease (12).

A Diagnostic Score for Molecular Analysis of Hereditary Autoinflammatory Syndromes With Periodic Fever in Children

OBJECTIVE To identify a set of clinical parameters that can predict the probability of carrying mutations in one of the genes associated with hereditary autoinflammatory syndromes. METHODS A total of 228 consecutive patients with a clinical history of periodic fever were screened for mutations in the MVK, TNFRSF1A, and MEFV genes, and detailed clinical information was collected. A diagnostic score was formulated based on univariate and multivariate analyses in genetically positive and negative patients (training set). The diagnostic score was validated in an independent set of 77 patients (validation set). RESULTS Young age at onset (odds ratio [OR] 0.94, P = 0.003), positive family history of periodic fever (OR 4.1, P = 0.039), thoracic pain (OR 4.6, P = 0.05), abdominal pain (OR 33.1, P < 0.001), diarrhea (OR 3.3, P = 0.028), and oral aphthosis (OR 0.2, P = 0.007) were found to be independently correlated with a positive genetic test result. These variables were combined in a linear score whose ability to predict a positive result on genetic testing was validated in an independent data set. In this latter set, the diagnostic score revealed high sensitivity (82%) and specificity (72%) for discriminating patients who were genetically positive from those who were negative. In patients with a high probability of having a positive result on genetic testing, a regression tree analysis provided the most reasonable order in which the genes should be screened. CONCLUSION The proposed approach in patients with periodic fever will increase the probability of obtaining positive results on genetic testing, with good specificity and sensitivity. Our results further help to optimize the molecular analysis by suggesting the order in which the genes should be screened.

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.

INFEVERS: the Registry for FMF and hereditary inflammatory disorders mutations

We have established the INFEVERS--INternet periodic FEVERS--website (which is freely accessible at http://fmf.igh.cnrs.fr/infevers/). Our objectives were to develop a specialist site to gather updated information on mutations responsible for hereditary inflammatory disorders: i.e. Familial Mediterranean Fever (FMF), TRAPS (TNF Receptor 1A Associated Syndrome), HIDS (HyperIgD Syndrome), MWS (Muckle-Wells Syndrome)/FCU (Familial Cold Urticaria)/CINCA (Chronic Infantile Neurological Cutaneous and Articular Syndrome). Contributors submit their novel mutations through a 3 step form. Depending on the disease concerned, a member of the editorial board is automatically solicited to overview and validate new submissions, via a special secured web interface. If accepted, the new mutation is available on the INFEVERS web site and the discoverer, who is informed by email, is credited by having his/her name and date of the discovery on the site. The INFEVERS gateway provides researchers and clinicians with a common access location for information on similar diseases, allowing a rapid overview of the corresponding genetic defects at a glance. Furthermore, it is interactive and extendable according to the latest genes discovered.

MEFV mutations in Behçet's disease.

Familial Mediterranean fever (FMF) and Behçets disease (BD), both inflammatory diseases, are highly prevalent in the Middle Eastern and Mediterranean populations. FMF is a Mendelian autosomic recessive disease linked to MEFV, a gene of unknown function. BD in contrast is a polyfactorial disease associated with the major histocompatibility complex. Because FMF and BD have epidemiological similarities, we asked whether the FMF gene was implicated in BD. We screened for the common MEFV mutations a cohort of 114 chromosomes from definite BD patients [meeting the criteria of the International study group] and probable cases [meeting at least two of these criteria]. We screened in parallel an ethnically matched cohort of FMF and control chromosomes. The M694V, V726A and E148Q mutations tended to be more frequent in definite BD (2.6%, 2.6%, and 5.2%, respectively) than in controls (0%, 0%, and 2.2%). The P706 polymorphism was found in 10.5% of the probable BD chromosomes, but in only 1.6% of the controls (p=0.01). Because some MEFV mutations were more frequent in BD than in controls, we suggest that they may act as additional susceptibility factors in BD. Hum Mutat 16:271–272, 2000.

Mutations Causing Familial Biparental Hydatidiform Mole Implicate C6orf221 as a Possible Regulator of Genomic Imprinting in the Human Oocyte

Familial biparental hydatidiform mole (FBHM) is the only known pure maternal-effect recessive inherited disorder in humans. Affected women, although developmentally normal themselves, suffer repeated pregnancy loss because of the development of the conceptus into a complete hydatidiform mole in which extraembryonic trophoblastic tissue develops but the embryo itself suffers early demise. This developmental phenotype results from a genome-wide failure to correctly specify or maintain a maternal epigenotype at imprinted loci. Most cases of FBHM result from mutations of NLRP7, but genetic heterogeneity has been demonstrated. Here, we report biallelic mutations of C6orf221 in three families with FBHM. The previously described biological properties of their respective gene families suggest that NLRP7 and C6orf221 may interact as components of an oocyte complex that is directly or indirectly required for determination of epigenetic status on the oocyte genome.