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Biomedical subjects

I Touitou

Publications and source records attributed to I Touitou.

At least 19 recordsLinked to original sources
PubMed2007

Autoinflammatory gene mutations in Behçet's disease.

BACKGROUND: Behçet's disease (BD) shares clinical features with well-recognised autoinflammatory disorders. In addition, mutations in genes for familial Mediterranean fever and tumour necrosis factor receptor-associated periodic syndrome have been reported to have increased in patients with BD. PATIENTS AND METHODS: DNA samples from 97 patients with BD and 51 matched healthy controls were analysed for the mevalonate kinase (MVK), cold-induced autoinflammatory syndrome 1 (CIAS1) and proline/serine/threonine phosphatase-interacting protein 1 (PSTPIP1) genes, responsible for mevalonate kinase deficiency (MKD), cryopyrin associated periodic syndromes (CAPS) and pyogenic sterile arthritis, pyoderma gangrenosum and acne (PAPA) syndrome, respectively. Over 90% of known mutations were screened using restriction fragment length polymorphism analysis and/or sequencing. RESULTS: Two patients had paired mutations in the MVK gene (genotypes V377I/V377I and V377I/S135L) and displayed typical features of BD and MKD. Another was heterozygotic for the V377I genotype. The V198M mutation in the CIAS1 gene was identified in one patient with typical BD but no symptoms of CAPS. No mutations were identified in the control group. PSTPIP1 analysis revealed a new exon 10 insertion variant (c.741+33_741+34insGT) in 2 of 97 patients and in 1 of 51 controls (p>0.05), indicating that it is a polymorphism rather than a true mutation. DISCUSSION: This study could not demonstrate any significant increases in MVK, CIAS1 or PSTPIP1 mutations in patients with BD as compared with controls.

Adaptor Proteins, Signal Transducing↗
PubMed2006

A decision tree for genetic diagnosis of hereditary periodic fever in unselected patients.

BACKGROUND: The diagnostic value of molecular analysis of the familial Mediterranean fever (FMF) gene (Mediterranean fever (MEFV)) has been well established only in patients selected on the basis of ethnic background or clinical criteria. Genetic diagnosis for other hereditary periodic fever syndromes has been poorly evaluated. OBJECTIVE: To determine the diagnostic contribution of genetic tests for hereditary periodic syndromes in a large, unselected series of patients. METHODS: A retrospective study was conducted on 1941 patients referred to us for FMF genetic tests between 1997 and 2005. MEFV genotypes were compared with clinical data to appraise criteria for FMF diagnosis. Genetic tests for tumour necrosis factor receptor-associated periodic syndrome (TRAPS), hyperimmunoglobulinaemia D syndrome (HIDS) and cryopyrin-associated periodic syndromes (CAPS) were also reviewed. RESULTS: 71% of the 1574 patients with enough data had a clinical diagnosis of FMF according to the widely used Israeli criteria. Two MEFV mutations were found in only 409 patients of this subgroup (sensitivity = 37%) and in 15 (3.3%) of the patients with an improbable clinical diagnosis of FMF (specificity = 97%). Molecular diagnosis for alternate hereditary periodic syndromes was carried out in 456 of the patients having a non-conclusive FMF genetic test. A positive diagnosis was obtained in 31 of these patients (TRAPS (n = 19), HIDS (n = 4) and CAPS (n = 8)). CONCLUSIONS: First-line MEFV mutation screening in patients with clinically typical FMF may be appropriate only in particular areas. To optimise genetic diagnosis, we propose a decision tree, which, with the advice of an expert practitioner, could help redirect test indications towards non-FMF hereditary periodic syndromes.

Adolescent↗
PubMed2003

Identification of an autosomal recessive mode of inheritance in paediatric Behçet's families by segregation analysis.

We have conducted a segregation analysis in order to characterise the transmission of Behçet Disease (BD), a multifactorial condition with a strong genetic component. Complete information about BD status and pedigree was obtained on 104 probands from our database. We used the criteria of the International Study Group for BD (ISBD) to delineate the clinical status of the sibs: possible BD (patients meeting two criteria), or ascertained BD (patients meeting at least three criteria). A proband was defined as "paediatric" when he/she completed ISBD criteria before/by the age of 16 years. Families were distinguished as paediatric (n = 67) (ascertained through a paediatric proband), and non-paediatric (n = 37) ones. An Expectation Maximization (EM) algorithm was used to estimate the Mendelian segregation ratio P in nuclear families (two parents and their offspring). The maximum likelihood estimate: Pcirc; = 0.248, calculated in the paediatric data set, was consistent with the theoretical value of P = (1/4) for autosomal recessive inheritance, whereas the Pcirc; value was 0.08 when using the non-paediatric data set. Our work provides the first evidence of genetic heterogeneity in BD, and of the existence of a Mendelian entity in the paediatric BD subgroup. Previous studies failed to show any simple mode of inheritance in BD, probably because they were performed on the whole BD population.

Behcet Syndrome↗
PubMed2002

Enhanced cytokine mRNA levels in attack-free patients with familial Mediterranean fever.

Familial Mediterranean fever (FMF) is a recessively inherited inflammatory disorder, characterized by recurrent attacks of fever and serositis. Screening of mutations in the causing gene (MEFV) now allows accurate diagnosis of FMF among other inflammatory conditions. It is well documented that secreted levels of some pro-inflammatory cytokines are elevated in FMF. Here, we investigated cytokine expression at the transcriptional level, in patients that could be genetically ascertained. We have measured the transcript abundance of tumor necrosis factor alpha, interleukin-1beta, interleukin-6 and interleukin-8, in circulating leukocytes and shown that these were more elevated in attack-free FMF patients than in controls (P=0.01, P=0.008, P=0.02, P=0.001 respectively). There was no significant difference according to MEFV genotype or colchicine treatment. Our results suggest that cytokine transcriptional pathways are misregulated in attack-free FMF patients, and further supports the hypothesis that these patients have subclinical inflammation between attacks.

Colchicine↗
PubMed2001

The MICA region determines the first modifier locus in familial Mediterranean fever.

OBJECTIVE: Familial Mediterranean fever (FMF) is a genetically recessive inflammatory disease caused by mutations in the MEFV gene. Most patients of non-Ashkenazi Jewish ancestry or those who are homozygous for M694V manifest a severe disease course, but some express a mild form of the disease. We therefore searched for other genes which could possibly be implicated in the disease phenotype. We tested MICA (major histocompatibility complex class I chain-related gene A) because it has been associated with a number of other inflammatory disorders. METHODS: One hundred fifty FMF probands and their family members were evaluated. The MEFV gene was screened by a combination of denaturing gradient-gel electrophoresis, restriction fragment length polymorphism, and amplification refractory mutation system. The MICA transmembrane polymorphism in exon 5 was analyzed after biotin-labeled polymerase chain reaction products were loaded onto sequencing gels and subjected to autoradiography. RESULTS: The contribution of MICA to the FMF phenotype was confirmed after adjustment for the patient's ancestry and for the MEFV genotype. MEFV was individually the most important prognostic factor for the disease. However, the impact of M694V homozygosity on the age at disease onset (OR 2.3) was aggravated if patients also inherited MICA-A9 (OR 6.3). In contrast, the frequency of attacks was found to be dramatically reduced (OR 0.16) in patients with MICA-A4. CONCLUSION: We have identified the first FMF modifier locus, MICA. FMF is the first model of a Mendelian disease associated with MICA. These results clarify, at least partly, the inconsistent phenotype-MEFV correlation in FMF.

Alleles↗
PubMed2001

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.

Familial Mediterranean Fever↗
PubMed2001

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.

Africa, Northern↗
PubMed2000

MEFV mutations in Behçet's disease.

Familial Mediterranean fever (FMF) and Behçet's 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.

Africa, Northern↗
PubMed2000

Familial Mediterranean fever in the 'Chuetas' of Mallorca: a question of Jewish origin or genetic heterogeneity.

Familial Mediterranean fever (FMF) is a hereditary disease commonly found among Jews, Armenians, Turks and Arabs. Recently, FMF was found in the 'Chuetas', a unique community on the island of Mallorca (Spain). To address the question of their possible Jewish origin, we analysed markers known to be linked to the gene responsible for FMF in Jews (MEFV) in this population. We found that 1/3 of the 16p13.3 chromosomes of the 'Chuetas' FMF patients bore the major ancestral haplotypes (S,S2) and their corresponding M694V and E148Q mutations, displayed by Jews from North Africa. Furthermore, we also detected a novel mutation (L110P) in this community. Yet 2/3 of these patients bore S negative haplotypes and lack the mutations commonly known to cause FMF. These results confirm that at least some of the 'Chuetas' share a common origin with Jews. However, they also provide evidence for the possibility of genetic heterogeneity in this disorder.

Amino Acid Substitution↗
PubMed2000

Phenotype-genotype correlation in 91 patients with familial Mediterranean fever reveals a high frequency of cutaneomucous features.

OBJECTIVES: To describe the clinical manifestations of familial Mediterranean fever (FMF) in 91 patients from 47 families and provide data from the genetic study. P:atients and methods. We conducted a retrospective chart review of 91 patients (including 83 children aged <15 yr) from 47 families through a questionnaire and a specific database. The genetic analysis included complete screening of known mutations of the MEFV gene on chromosome 16p13.3. A positive diagnosis required at least two mutations, one on each chromosome. RESULTS: Our panel included 52 females and 39 males, with a mean age of 7.27 yr. Of the 47 families, 31 were non-Ashkenazi Jews, 10 were Armenians and six were from other ethnic groups. Clinical features included fever (100%), peritonitis (86%), pleuritis (56%), arthritis (34%) and myalgias (27%). We observed a high rate of cutaneous manifestations (47%); erythema, oedema and recurrent oral ulcers were the most frequent. Phenotype-genotype correlations showed a significant association of M694V homozygosity with earlier age of onset (P: = 0.044), fever >39 degrees C (P: = 0. 002), pleural crisis (P: = 0.0044), splenomegaly (P: = 0.0005) and arthritis (P: = 0.001). Associations with mucocutaneous features were as follows: erysipelas-like erythema (P: = 0.012), oedema (P: = 0.61, not significant) and oral ulcers (P: = 0.45, not significant). CONCLUSION: New phenotype-genotype correlations emerged from our study: homozygosity for the M694V mutation was associated with intensity of fever, splenomegaly and with erysipelas-like erythema. Apart from erysipelas-like erythema, no significant association was found between other cutaneous features and the genotype.

Adolescent↗
PubMed1999

Familial aggregation in Behçet's disease: high frequency in siblings and parents of pediatric probands.

OBJECTIVE: To examine familial aggregation of Behçet's disease (BD) in pediatric compared with non-pediatric patients. METHODS: A retrospective study was conducted to analyze data collected from 572 patients with BD in whom the diagnosis was made with criteria defined by the International Study Group for BD. The age of attaining criteria (the age at which the patient met the study group criteria) was evaluated for each patient. Recurrence risks were calculated for the pediatric group from information provided by 45 families. RESULTS: Of the 505 patients from whom the age of attaining criteria could be ascertained, 106 showed definitive BD before the age of 16 years and were considered as pediatric patients with BD; the other 399 were classified as non-pediatric patients. Thirteen of the 106 pediatric patients (12.3%) and only 9 of the 399 non-pediatric patients (2.2%) had relatives affected by BD. This excess of familial cases in the pediatric group compared with the non-pediatric group was significant (P <.0001, chi2 analysis). Moreover, the mean age of attaining criteria in familial cases (17. 95 years [SD = 8.62]) was significantly lower than in sporadic cases (27.28 years [SD = 11]; P <.0001, Student t test). The recurrence risk among siblings and parents who met the International Study Group criteria was 0.1. CONCLUSION: Our data support the hypothesis of a genetic component in the pathogenesis of BD, and we propose the inclusion of familial history in the definition of pediatric BD.

Adolescent↗
PubMed1998

[Genetic diagnosis of periodic disease].

INTRODUCTION: Periodic disease is a hereditary disorder. Until recently its diagnosis was essentially based on clinical criteria. When the clinical picture was incomplete or atypical, it often required elimination of other diagnoses which sometimes involved extensive and useless investigations. Diagnosis was consequently delayed or irrelevant, with the risk of renal failure when the patient was not treated (or tardily treated). CURRENT KNOWLEDGE AND KEY POINTS: Efforts of molecular geneticists have allowed to track and recently to identify the gene (MEFV) responsible for this disease. Today blood sampling enables identification of the causative mutations, sometimes even before the onset of symptoms. FUTURE PROSPECTS AND PROJECTS: Four mutations clustered on exon 10 already account for 74% of cases in patients originating from the most affected populations and presenting with complete clinical picture. Identification of rare mutations should progressively allow improvement of the test sensitivity, especially in patients with a less typical form of the disease.

Chromosomes, Human, Pair 16↗