The Population Genetics of Familial Mediterranean Fever: A Meta-Analysis Study

Genetic and clinical features of familial mediterranean fever (FMF) in a homogeneous cohort of patients from South-Eastern Italy

Familial Mediterranean Fever (FMF) is linked with the MEFV gene and is the commonest among monogenic autoinflammatory diseases, with high prevalence in the Mediterranean basin. Although the clinical presentation of FMF has a major role in diagnosis, genotype/phenotype correlations and the role of "benign" gene variants (as R202Q) appear highly variable and incompletely clear, making difficult to select the most effective strategy in the management of patients. Aim of the present study was to investigate the clinical presentation and the genetic background in a homogenous cohort of patients from Apulia (south eastern Italy). We investigated 217 patients with a clinical suspect of autoinflammatory diseases, who were characterized for the occurrence of specific symptoms and with next generation sequencing by a 4-gene panel including MEFV, MVK, NLRP3 and TNFRSF1A. A genetic change was identified in 122 (53.7%) patients, with 161 different MEFV variants recorded in 100 individuals, 10 variants in NLRP3, and 6 each in TNFRSF1A and MVK. The benign variant R202Q was largely prevalent (41.6% of all MEFV variants). When patients were selected according the number of pathogenic MEFV variants (0, 1, or 2 pathogenic variants), results failed to show significant links between the frequency of symptoms and the number of pathogenic variants. Only family history and Pras score (indicative for severity of disease) predicted the presence of pathogenic variants, as compared with carriers of variants considered of uncertain significance or benign. Fever >38 °C and arthralgias appeared more frequently in R202Q-positive patients than in non-R202Q carriers. These two subgroups showed comparable duration of fever, occurrence of myalgia, abdominal and chest pain, Pras, and IFFS scores. In conclusion, results confirm that FMF manifests in mild form in non-middle eastern patients. This possibility partly affects the reliability of clinical criteria/scores. Furthermore, the presence of the R202Q variant might not be completely neutral in selected groups of patients.

An Update on Familial Mediterranean Fever

(1) Background: Familial Mediterranean Fever (FMF) is the prototypal autoinflammatory disease, characterized by recurrent bursts of neutrophilic inflammation. (2) Methods: In this study we look at the most recent literature on this condition and integrate it with novel information on treatment resistance and compliance. (3) Results: The canonical clinical presentation of FMF is in children with self-limited episodes of fever and polyserositis, associated with severe long-term complications, such as renal amyloidosis. It has been described anecdotally since ancient times, however only recently it has been characterized more accurately. We propose an updated overview on the main aspects of pathophysiology, genetics, diagnosis and treatment of this intriguing disease. (4) Conclusions: Overall, this review presents the all the main aspects, including real life outcome of the latest recommendation on treatment resistance of FMF, a disease, that not only helped understanding the pathophysiology of the auto inflammatory process but also the functioning of the innate immune system itself.

Familial Mediterranean Fever in Spain: Time Trend and Spatial Distribution of the Hospitalizations

Familial Mediterranean Fever (FMF) is a rare, hereditary, auto-inflammatory disease. The aims of this study were to explore the time trend and geographical distribution of hospitalizations in Spain from 2008 to 2015. We identified hospitalizations of FMF from the Spanish Minimum Basic Data Set at hospital discharge, using ICD-9-CM code 277.31. Age-specific and age-adjusted hospitalization rates were calculated. The time trend and the average percentage change were analyzed using Joinpoint regression. Standardized morbidity ratios were calculated and mapped by province. A total of 960 FMF-related hospitalizations (52% men) were identified across the period 2008-2015, with an increase in hospitalizations of 4.9% per year being detected (p < 0.05). The risk of hospitalization was higher than expected for the national total (SMR > 1) in 13 provinces (5 in the Mediterranean area), and lower (SMR < 1) in 14 provinces (3 in the Mediterranean area). There was an increase in hospitalizations of patients with FMF in Spain throughout the study period, with a risk of hospitalization that was higher, though not exclusively so, in provinces along the Mediterranean coast. These findings contribute to the visibility of FMF and provide useful information for health planning. Further research should take into account new population-based information, in order to continue monitoring this disease.

Assessment of Surrogate Markers for Cardiovascular Disease in Familial Mediterranean Fever-Related Amyloidosis Patients Homozygous for M694V Mutation in MEFV Gene

Cardiovascular disease (CVD) remains underestimated in familial Mediterranean fever-associated AA amyloidosis (FMF-AA). We aimed to compare early markers of endothelial dysfunction and atherosclerosis in FMF-AA with a homozygous M694V mutation (Group 1 = 76 patients) in the Mediterranean fever (MEFV) gene and in patients with other genotypes (Group 2 = 93 patients). Measures of increased risk for future CVD events and endothelial dysfunction, including flow-mediated dilatation (FMD), pentraxin-3 (PTX3), and carotid intima-media thickness (cIMT), and fibroblast growth factor 23 (FGF23) as a marker of atherosclerotic vascular disease were compared between groups. The frequency of clinical FMF manifestations did not differ between the two groups apart from arthritis (76.3% in Group 1 and 59.1% in Group 2, p < 0.05). FMD was significantly lower in Group 1 when compared with Group 2 (MD [95% CI]: −0.6 [(−0.89)−(−0.31)]). cIMT, FGF23, and PTX3 levels were higher in Group 1 (cIMT MD [95% CI]: 0.12 [0.08−0.16]; FGF23 MD [95% CI]: 12.8 [5.9−19.6]; PTX3 MD [95% CI]: 13.3 [8.9−17.5]). In patients with FMF-AA, M694V homozygosity is associated with lower FMD values and higher cIMT, FGF23, and PTX3 levels, suggesting increased CVD risk profiles. These data suggest that a genotype−phenotype association exists in terms of endothelial dysfunction and atherosclerosis in patients with FMF-AA.

Clinical and molecular evaluation of MEFV gene variants in the Turkish population: a study by the National Genetics Consortium

Familial Mediterranean fever (FMF) is a monogenic autoinflammatory disorder with recurrent fever, abdominal pain, serositis, articular manifestations, erysipelas-like erythema, and renal complications as its main features. Caused by the mutations in the MEditerranean FeVer (MEFV) gene, it mainly affects people of Mediterranean descent with a higher incidence in the Turkish, Jewish, Arabic, and Armenian populations. As our understanding of FMF improves, it becomes clearer that we are facing with a more complex picture of FMF with respect to its pathogenesis, penetrance, variant type (gain-of-function vs. loss-of-function), and inheritance. In this study, MEFV gene analysis results and clinical findings of 27,504 patients from 35 universities and institutions in Turkey and Northern Cyprus are combined in an effort to provide a better insight into the genotype-phenotype correlation and how a specific variant contributes to certain clinical findings in FMF patients. Our results may help better understand this complex disease and how the genotype may sometimes contribute to phenotype. Unlike many studies in the literature, our study investigated a broader symptomatic spectrum and the relationship between the genotype and phenotype data. In this sense, we aimed to guide all clinicians and academicians who work in this field to better establish a comprehensive data set for the patients. One of the biggest messages of our study is that lack of uniformity in some clinical and demographic data of participants may become an obstacle in approaching FMF patients and understanding this complex disease.

Identification of an Anti-Integrin αvβ6 Autoantibody in Patients With Ulcerative Colitis

BACKGROUND AND AIMS

Ulcerative colitis is the most frequent type of inflammatory bowel disease and is characterized by colonic epithelial cell damage. Although involvement of autoimmunity has been suggested in ulcerative colitis, specific autoantigens/antibodies have yet to be elucidated.

METHODS

Using 23 recombinant integrin proteins, we performed enzyme-linked immunosorbent assays on sera from patients with ulcerative colitis and controls. Integrin expression and IgG binding in the colon tissues of patients with ulcerative colitis and controls were examined using immunofluorescence and coimmunoprecipitation, respectively. The blocking activity of autoantibodies was examined using solid-phase binding and cell adhesion assays.

RESULTS

Screening revealed that patients with ulcerative colitis had IgG antibodies against integrin αvβ6. In the training and validation groups, 103 of 112 (92.0%) patients with ulcerative colitis and only 8 of 155 (5.2%) controls had anti-integrin αvβ6 antibodies (P < .001), resulting in a sensitivity of 92.0% and a specificity of 94.8% for diagnosing ulcerative colitis. Anti-integrin αvβ6 antibody titers coincided with ulcerative colitis disease activity, and IgG1 was the major subclass. Patient IgG bound to the integrin αvβ6 expressed on colonic epithelial cells. Moreover, IgG of patients with ulcerative colitis blocked integrin αvβ6-fibronectin binding through an RGD (Arg-Gly-Asp) tripeptide motif and inhibited cell adhesion.

CONCLUSIONS

A significant majority of patients with ulcerative colitis had autoantibodies against integrin αvβ6, which may serve as a potential diagnostic biomarker with high sensitivity and specificity.

Familial Mediterranean Fever and COVID-19: Friends or Foes?

Familial Mediterranean Fever (FMF) and COVID-19 show a remarkable overlap of clinical symptoms and similar laboratory findings. Both are characterized by fever, abdominal/chest pain, elevation of C-reactive protein, and leukocytosis. In addition, colchicine and IL-1 inhibitors treatments that are effective in controlling inflammation in FMF patients have recently been proposed for off-label use in COVID-19 patients. Thus, FMF may resemble a milder recapitulation of the cytokine storm that is a hallmark of COVID-19 patients progressing to severe disease. We analyzed the sequence of the MEFV-encoded Pyrin protein - whose mutations cause FMF- in mammals, bats and pangolin. Intriguingly, although Pyrin is extremely conserved in species that are considered either a reservoir or intermediate hosts for SARS-CoV-2, some of the most common FMF-causing variants in humans are present as wildtype residues in these species. We propose that in humans, Pyrin may have evolved to fight highly pathogenic infections.

Differential mutational profiles of familial Mediterranean fever in North Africa

Familial Mediterranean fever (FMF) is a recessive autoinflammatory disease, mainly occurring in the eastern Mediterranean. In these populations, the five FMF founder mutations are differently distributed. In Algeria, the FMF-causing variants remain poorly explored. This retrospective study aims to report the mutational profile of Algerian FMF patients and to compare it with North African FMF patients. One hundred eighty-three unrelated patients clinically suspected of FMF were recruited from various Algerian hospitals (2007-2015) and tested for mutations in exon 10 of MEFV gene. Molecular analysis identified 144 mutant alleles among 87 of 183 patients (47.5%). p.M694I was the most prevalent pathogenic allele, accounting for 63.2% of mutant alleles, followed by p.M694V and p.M680I occurring with a same frequency (14.5%). Others, p.A744S (6.2%) and p.I692del (1.3%), are less frequent. Interestingly, p.M694I was the most recurrent in patients with renal AA-amyloidosis. Our results provide the first genetic data on FMF in Algeria, demonstrating the predominance of p.M694I and the absence of p.V726A, compared to other North African countries (Morocco, Tunisia, and Egypt). In conclusion, North African FMF patients display differential mutational profiles that may result from the difference in ethnic origin and the genetic heterogeneity among these populations.

Ancient familial Mediterranean fever mutations in human pyrin and resistance to Yersinia pestis

Familial Mediterranean fever (FMF) is an autoinflammatory disease caused by homozygous or compound heterozygous gain-of-function mutations in MEFV, encoding pyrin, an inflammasome protein. Heterozygous carrier frequencies for multiple MEFV mutations are high in several Mediterranean populations, suggesting that they confer selective advantage. Among 2,313 Turks, we found extended haplotype homozygosity flanking FMF-associated mutations, indicating evolutionarily recent positive selection of FMF-associated mutations. Two pathogenic pyrin variants independently arose >1,800 years ago. Mutant pyrin interacts less avidly with Yersinia pestis virulence factor YopM than wild type human pyrin, thereby attenuating YopM-induced IL-1β suppression. Relative to healthy controls, leukocytes from FMF patients harboring homozygous or compound heterozygous mutations and from asymptomatic heterozygous carriers released heightened IL-1β specifically in response to Y. pestis. Y. pestis-infected Mefv^M680I/M680I FMF knock-in mice exhibited IL-1-dependent increased survival relative to wild-type knock-in mice. Thus, FMF mutations that were positively selected in Mediterranean populations confer heightened resistance to Y. pestis.

The Use of Interleukine-1 Inhibitors in Familial Mediterranean Fever Patients: A Narrative Review

Purpose: Familial Mediterranean fever (FMF) is the most common monogenic auto-inflammatory disease characterized by recurrent attacks of fever and serositis. It is associated with mutation in pyrin inflammasome leading to interleukin-1 (IL-1) over secretion. Although colchicine is the first line treatment in FMF, 5-10% of patients are reported in literature as non-responders. Colchicine is not always well-tolerated due either to its direct toxicity or to co-morbidities that preclude the administration of its proper dosage. For these patients an alternative or additional treatment to colchicine is necessary. This literature review reports the published data regarding the use of IL-1 inhibitors in Familial Mediterranean Fever. Results: There is no uniform definition of colchicine resistance, but the different studies of treatment with IL-1 inhibitors provide evidence of IL-1 pathogenic role in colchicine-resistant FMF. IL-1 inhibition is an efficacious option for controlling and preventing flares -at least at the short term- in FMF patients who are insufficiently controlled with colchicine alone. Although canakinumab is the only approved drug in Europe for colchicine resistant FMF treatment, experience with anakinra is also substantial. In the absence of comparative studies both treatments seem to be an equal option for the management of these patients. Overall the safety profile of IL-1 inhibitors seems not different in FMF patients than in the other diseases and can be considered as globally safe. The main side effects are local injection site reactions and infections. Conclusion: IL-1 inhibitors have the potential to improve patient outcome even in FMF patients with co-morbidities or severe complications in whom inflammation control is difficult to achieve with colchicine alone. Nevertheless, current data are limited and further evaluation of long-term efficacy and safety of IL-1 inhibitors are necessary, in order to provide robust evidence in this domain.

Autoinflammation: Lessons from the study of familial Mediterranean fever

Autoinflammatory disorders represent a heterogeneous group of systemic inflammatory diseases caused by genetic or acquired defects in key components of the innate immunity. Familial Mediterranean fever (FMF) is the most common among the other clinical phenotypes of the rare hereditary periodic fevers (HPFs) syndromes. FMF is associated with mutations in the MEFV gene encoding pyrin and is characterized by recurrent, often stress-provoked attacks of fever and serositis, but sometimes also by chronic subclinical inflammation. FMF is prevalent in Greece and other countries of the eastern Mediterranean region. Over the last 17 years, our group has focused on FMF as a model suitable for the research on innate immunity and particularly the role of neutrophils. Therefore, the study of Greek patients with FMF has yielded lessons across several levels: the epidemiology of the disease in Greece, the spectrum of its clinical manifestations and potential overlaps with other idiopathic inflammatory conditions, the demonstration of its rather complex and heterogeneous genetic background and the suggestion of a novel mechanism involved in the crosstalk between environmental stress and inflammation. Mechanistically, during FMF attack, neutrophils release chromatin structures called neutrophil extracellular traps (NETs), which are decorated with bioactive IL-1β. REDD1 (regulated in development and DNA damage responses 1), that encodes a stress-related mTOR repressor, has been found to be the most significantly upregulated gene in neutrophils during disease attacks. Upon adrenergic stress, REDD1-induced autophagy triggers a pyrin-driven IL-1β maturation, and the release of IL-1β-bearing NETs. Consequently, not only the mode of action of IL-1β-targeting therapies is explained, but also new treatment prospects emerge with the evaluation of old or the design of new drugs targeting autophagy-induced NETosis. Information gained from FMF studies may subsequently be applied in more complex but still relevant inflammatory conditions, such as adult-onset Still's disease, gout, ulcerative colitis and Behçet's disease.

Long-term follow-up of paediatric MEFV carriers

Although familial Mediterranean fever (FMF) is inherited autosomal recessively, some heterozygotes may express disease phenotype and require therapy. To date, there is no study in the literature about how to follow-up Mediterranean fever (MEFV) heterozygotes who do not fulfil FMF criteria in the paediatric age group. This study aims to share a single-centre experience of the long-term clinical and laboratory follow-up of paediatric MEFV carriers. We reviewed the charts of 69 children who were heterozygous for MEFV variants. All children were followed-up with their routine analysis and serum amyloid A levels every 6 months. Thirty-nine children had pathogenic mutations and 30 children had variants of unknown significance. The mean follow-up was 3.2 ± 1.6 years (min 2 years, max 6 years). The children with pathogenic mutations had significantly higher mean SAA levels than the children with variants of unknown significance (p = 0.018); however, the mean CRP and ESR were similar. Besides, the children with pathogenic mutations complained of fever episodes significantly more than the children with variants of unknown significance (p = 0.04). None of the children had persistent proteinuria in the follow-up. We started colchicine in only two patients who were M694V heterozygous. Both patients had family history for FMF and fulfilled the disease criteria after 2 years of follow-up. Neither of these patients had persistently elevated acute phase reactants in their routine follow-up. This study suggested that routine clinical follow-up is useful; however, routine periodic laboratory workup is not necessary among MEFV carriers.

Genetic epidemiology of familial Mediterranean fever through integrative analysis of whole genome and exome sequences from Middle East and North Africa

Familial Mediterranean fever (FMF), an autosomal recessive and rare autoinflammatory disease is caused by genetic mutations in the MEFV gene and is highly prevalent in the Mediterranean basin. Although the carrier frequency of specific disease variants in the MEFV gene has been reported from isolated studies, a comprehensive view of variants in the Mediterranean region has not been possible due to paucity of data. The recent availability of whole-genome and whole-exome datasets prompted us to study the genetic epidemiology of MEFV variants in the region. We assembled data from 5 datasets encompassing whole-genome and whole-exome datasets for 2115 individuals from multiple subpopulations in the region and also created a compendium for MEFV genetic variants, which were further systematically annotated as per the American College of Medical Genetics and Genomics (ACMG) guidelines. Our analysis points to significant differences in allele frequencies in the subpopulations, and the carrier frequency for MEFV genetic variants in the population to be about 8%. The MEFV gene appears to be under natural selection from our analysis. To the best of our knowledge, this is the most comprehensive study and analysis of population epidemiology of MEFV gene variants in the Middle East and North African populations.

Prevalence of common MEFV mutations and carrier frequencies in a large cohort of Iranian populations

Familial Mediterranean fever (FMF) is a hereditary autoinflammatory disorder caused by mutations in the MEFV gene. The disease is especially common among Armenian, Turkish, Jewish and Middle East Arab populations. To identify the frequency and the spectrum of common MEFV mutations in different Iranian populations, we investigated a cohort of 208 unselected asymptomatic individuals and 743 FMF patients. Nine hundred and fifty-one samples were analysed for the presence of 12 MEFV mutations by PCR and reverse-hybridization (FMF StripAssay, ViennaLab, Vienna, Austria). Confirmatory dideoxy sequencing of all MEFV gene exons was performed for 39 patients. Fifty-seven (27.4%) healthy individual carried mutant MEFV alleles. Three hundred and ninety-one (52.6%) FMF patients were found positive for either one (172/743; 23.1%), two or three MEFV mutations. Using dideoxy sequencing, three novel variants, A66P, R202W and H300Q, could be identified. Our analysis revealed an allele frequency and carrier rate of 15.6 and 27.4%, respectively, among healthy Iranians. Still moderate compared to neighbouring Armenia, but higher than in Turkey or Iraq, these data suggest that FMF is remarkably common among Iranian populations. E148Q was most frequent in the group of healthy individuals, whereas M694V was the most common mutation among FMF patients, thereby corroborating previous studies on MEFV mutational spectra in the Middle East. Accordingly, MEFV mutations are frequent in healthy Iranian individuals across different ethnic groups. Based on this finding, the awareness for FMF and the implementation of augmented carrier screening programmes considering the multiethnic nature of the Iranian population should be promoted.

Distribution of MEFV gene mutations and R202Q polymorphism in the Serbian population and their influence on oxidative stress and clinical manifestations of inflammation

BACKGROUND

The Mediterranean fever (MEFV) gene codes for protein pyrin, one of the regulators of inflammasome activity in innate immune cells. Mutations in this gene are considered the primary cause of Familial Mediterranean fever, but are also found in other monogenic and multifactorial autoinflammatory diseases. The aim of the study was to determine if healthy carriers of MEFV gene mutations and R202Q polymorphism have clinical manifestations of inflammation and impaired oxidative stress parameters.

METHODS

One hundred DNA samples from healthy volunteers (13.3 ± 8.87 years of age (mean ± SD); range 2-35) were sequenced by ABI PRISM 310 automated sequencer (PE Applied Biosystems, Norwalk, USA). The Eurofever questionnaire was used to collect retrospectively medical history data. Oxidative stress was determined by measuring spectrophotometrically thiobarbituric acid reactive substances (TBARS) in plasma and erythrocytes, as well as advanced oxidation protein products in plasma. Superoxide dismutase (SOD) activity was determined by McCord and Fridovich method in plasma and erythrocytes, while the catalase erythrocyte activity was assessed using a catalase ELISA kit.

RESULTS

We found heterozygous carriers of K695R/N mutations in 5 %, E148Q/N mutations in 6 %, R202Q homozygous polymorphism in 10 % and heterozygous R202Q alterations in 45 % of healthy volunteers. The MEFV mutation carriers and R202Q polymorphism homozygotes reported significantly more often recurrent febrile episodes (p = 0.009), diffuse abdominal pain (p = 0.025), and malaise (p = 0.012) compared to non-carriers. Erythrocyte TBARS levels and plasma SOD activity were higher in persons with MEFV mutations and R202Q/R202Q (p = 0.03 and p = 0.049, respectively).

CONCLUSIONS

Healthy individuals may bear E148Q and K695R MEFV gene mutations, as well as R202Q polymorphism in homozygous state. The determined gene alterations contribute to a subtle oxidative stress and may be associated with more frequent episodes of fever and unspecific inflammatory manifestations. An incomplete penetrance or variable expressivity of R202Q in populations of different ethnicity could influence the expression of autoinflammatory diseases phenotype.

Update on Pyrin Functions and Mechanisms of Familial Mediterranean Fever

Mutations in the MEFV gene, which encodes the protein named pyrin (also called marenostrin or TRIM20), are associated with the autoinflammatory disease familial Mediterranean fever (FMF). Recent genetic and immunologic studies uncovered novel functions of pyrin and raised several new questions in relation to FMF pathogenesis. The disease is clinically heterogeneous reflecting the complexity and multiplicity of pyrin functions. The main functions uncovered so far include its involvement in innate immune response such as the inflammasome assemblage and, as a part of the inflammasome, sensing intracellular danger signals, activation of mediators of inflammation, and resolution of inflammation by the autophagy of regulators of innate immunity. Based on these functions, the FMF-associated versions of pyrin confer a heightened sensitivity to a variety of intracellular danger signals and postpone the resolution of innate immune responses. It remains to be demonstrated, however, what kind of selective advantage the heterozygous carriage conferred in the past to be positively selected and maintained in populations from the Mediterranean basin.

Relationship between clinical findings and genetic mutations in patients with familial Mediterranean fever

BACKGROUND

Familial Mediterranean fever (FMF) is one of the most frequent genetic diseases encountered in the Mediterranean region. We aimed to investigate the correlation between genetic mutations and the clinical findings in 562 patients with FMF.

METHODS

In this retrospective cross-sectional study conducted with patients' files between 2006, and 2013, reverse hybridization assay for MEFV gene mutations was used and the 12 most frequent mutations were screened. Mutation types and clinical findings were compared with variance analysis.

RESULTS

The mean age was 6.9 ± 3.4 years (range, 1.8-11.6 years). The most common symptom was fever (97.3%). Thirty-four of the patients (6.04%) were admitted with periodic fever only. Of these patients, M694V was the most common mutation type (73.5%). The percentage of the patients predominantly presenting with recurrent abdominal pain was 77.78% and the most frequent mutations were M694V and E148Q. The rate of arthritis and arthralgia was significantly higher in patients with M694V and E148Q mutations. Chest pain was reported more often in patients homozygous for M694V (61.4%). Pericardial effusion was documented in the echocardiography of 10.9% of the 229 children with chest pain. Some patients had both FMF and Henoch Schönlein purpura (HSP), and were more likely to harbor either homozygote M694V or E148Q mutations. The frequency of episodes was higher in patients with homozygous M694V mutations (number of attacks = 4.4 ± 1.6/month). Proteinuria was detected in 106 patients of cases (29.2%), at an average of 854 ± 145 mg/L. Most of the patients with proteinuria and elevated serum amyloid-A had homozygous M694V mutation.

CONCLUSION

The most common mutation in children in Turkey with FMF is the M694V mutation. Recurrent abdominal pain, arthritis or arthralgia, chest pain, and pericarditis were commonly seen in patients with M694V and E148Q mutations.

Mediterranean Founder Mutation Database (MFMD): Taking Advantage from Founder Mutations in Genetics Diagnosis, Genetic Diversity and Migration History of the Mediterranean Population

The Mediterranean basin has been the theater of migration crossroads followed by settlement of several societies and cultures in prehistoric and historical times, with important consequences on genetic and genomic determinisms. Here, we present the Mediterranean Founder Mutation Database (MFMD), established to offer web-based access to founder mutation information in the Mediterranean population. Mutation data were collected from the literature and other online resources and systematically reviewed and assembled into this database. The information provided for each founder mutation includes DNA change, amino-acid change, mutation type and mutation effect, as well as mutation frequency and coalescence time when available. Currently, the database contains 383 founder mutations found in 210 genes related to 219 diseases. We believe that MFMD will help scientists and physicians to design more rapid and less expensive genetic diagnostic tests. Moreover, the coalescence time of founder mutations gives an overview about the migration history of the Mediterranean population. MFMD can be publicly accessed from http://mfmd.pasteur.ma.

Sonographic assessment of spleen size in Turkish migrants with Familial Mediterranean fever in Germany

OBJECTIVES

Familial Mediterranean fever (FMF) can be associated with splenomegaly. Prospective quantitative data are lacking. We performed a sonographic assessment of spleen size in patients with FMF and healthy control participants to assess its diagnostic value.

METHODS

Patients with FMF according to the criteria of Livneh et al (Arthritis Rheum 1997; 40:1879-1885) who were in an asymptomatic interval and control participants were prospectively included in this study in Germany and underwent sonographic measurement of the spleen as well as a structured interview and a physical examination. Patients and controls were Turkish migrants.

RESULTS

Thirty-six patients and 27 controls were included. Patients and controls did not differ significantly in age (mean ± SD, 34.8 ± 9.7 versus 33.3 ± 10.0 years, respectively; P = .56), sex, height, weight, or body mass index (26.7 ± 4.7 versus 26.1 ± 4.3 kg/m(2); P = .63). Spleen size was greater in patients than controls in width (4.3 ± 1.0 versus 3.7 ± 0.7 cm; P = .008) and also length (12.1 ± 1.9 versus 10.5 ± 1.4 cm; P = .001). Twenty-six of 36 patients (72.2%) had a history of appendectomy compared to 3 of 27 controls (11.1%; P < .001). The combination of an enlarged spleen (length >11 cm and/or width >4 cm) gave specificity of 100% (95% confidence interval, 87%-100%) and a positive predictive value of 100% (95% confidence interval, 78%-100%) for the diagnosis of FMF in our study.

CONCLUSIONS

Spleen size as evaluated by sonography is larger in patients with FMF compared to healthy controls. Most patients with FMF included in this study had undergone appendectomy. Familial Mediterranean fever should be considered as a differential diagnosis in Turkish migrants in Germany if the spleen is enlarged and a history of appendectomy is reported.

P wave dispersion and QT dispersion in adult Turkish migrants with familial mediterranean fever living in Germany

BACKGROUND

Familial Mediterranean Fever (FMF) is a hereditary autoinflammatory disease associated with subclinical inflammation, which includes atherosclerosis arising from endothelial inflammation, which in turn increases the risk of atrial or ventricular arrhythmias. Conduction abnormalities can be detected using the electrocardiographic (ECG) indices P and QT dispersion (Pdisp and QTdisp). Currently, it is unknown whether patients with FMF are more likely to have abnormalities of these ECG indices. Moreover, existing studies were conducted in countries with higher FMF prevalence. We therefore perform the first prospective study assessing Pdisp and QTdisp in adult FMF patients in Germany, where prevalence of FMF is low.

METHOD

Asymptomatic FMF patients (n=30) of Turkish ancestry living in Germany and age-matched healthy controls (n=37) were prospectively assessed using 12-lead ECG.

RESULTS

Patients and controls were comparable in gender and body mass index, and patients had higher erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and serum amyloid A (SAA) compared to controls (ESR: 23.7±14.3 vs. 16.1±13,3 mm/1(st)h, p=0.03, CRP: 0.73±0.9 vs. 0.26±0.4 g/dl, p=0.01, SAA: 3.14±4,8 vs. 0.37±0.3 mg/dl, p<0.01). No statistically significant difference between patients and controls respectively, for Pdisp (43.7±11.9 vs. 47.1±11.2ms, p=0.23), QTdisp (65.9±12.3 vs. 67.6±12.7 ms, p=0.58) or corrected QTdisp (cQTdisp: 73.9±15.0 vs. 76.0±13.3 ms, p=0.55) was found. No correlation could be found between Pdisp or QTdisp or cQTdisp and any of the biochemical markers of inflammation.

CONCLUSION

FMF patients living in Germany show a Pdisp and QTdisp comparable to healthy controls, with no increased risk of atrial or ventricular arrhythmias indicated.

Disease severity in adult patients of Turkish ancestry with familial mediterranean fever living in Germany or Turkey. Does the country of residence affect the course of the disease?

BACKGROUND

The environment may affect the course of familial Mediterranean fever (FMF).

OBJECTIVE

The objective of this study was to compare disease severity between adult FMF patients in Turkey (TR) and Germany (G).

METHODS

Adult FMF patients of Turkish ancestry on colchicine living in Turkey (n = 40) or G (n = 35) were compared. Disease severity, C-reactive protein (CRP), and erythrocyte sedimentation rate were assessed.

RESULTS

Groups differed significantly in the following aspects: age at onset of disease (TR: 15.6, G: 10.8 years; P = 0.02), delay between onset and initiation of colchicine treatment (TR: 6.8 years, G: 14.9 years; P < 0.001), female gender (TR: 80%, G: 57.1%; P = 0.04), and duration of disease (TR: 14.4 years, G: 23.4 years; P < 0.001). There was no significant difference in colchicine treatment concerning average dosing and duration of therapy. No significant difference could be found between the 2 groups in CRP and disease severity as assessed by the score of Pras et al. (Am J Med Genet. 1998;75:216-219) even after adjusting for potential confounding variables. Mean erythrocyte sedimentation rate was significantly higher among patients living in G (TR: 13.2 mm/first hour, G: 26.3 mm/first hour; P < 0.001). Among patients living in Germany, there was a significant difference in age at FMF onset depending on their country of birth (born in TR: 14.9 years, born in G: 6.9 years; P = 0.0001).

CONCLUSIONS

In adult FMF patients living in Turkey or Germany, no difference in disease activity or CRP could be found. German patients were younger at onset of disease and had a longer delay between onset and initiation of colchicine treatment.

From the Mediterranean to the sea of Japan: the transcontinental odyssey of autoinflammatory diseases

Autoinflammatory diseases are comprehensively caused by aberrant production of proinflammatory cytokines and are revealed by cyclically and spontaneously occurring inflammatory events. Over the last decade, there has been a revolution in the understanding of periodic fever syndromes, cryopyrinopathies, and skin disorders with pyogenic, granulomatous, or dystrophic features, which have been recognized across different countries spanning from the Mediterranean basin to the Japanese archipelago. Many children and adults with autoinflammatory diseases continue to elude diagnosis, and the diagnostic delay of many years puts these patients at risk of long-term severe complications, such as amyloidosis. Any hint of suspicion of autoinflammatory disease thus needs to be highlighted in various medical specialties, and this review examines their frequencies around the world, trying to match them with geographic location, ethnic and genetic data, in an attempt to realize a geoepidemiologic map for most of these conditions.

Bloody Diarrhea as a Presentation Manifestation of Familial Mediterranean Fever in a Patient with Compound Heterozygote Mutations of the MEFV Gene

Familial Mediterranean fever (FMF) is a hereditary autoinflammatory disease characterized by episodic fever and inflammatory polyserositis, which could lead to a variety of manifestations, including recurrent abdominal pain. Herein, a 12-year-old boy who has suffered from fever and bloody diarrhea since early childhood is described. All structural and underlying disorders leading to bleeding were excluded. Genetic studies indicated compound heterozygote mutations of M680I/R761H in the MEFV gene, which confirmed the diagnosis of FMF. Therefore, treatment with colchicine was started, which led to symptom relief. As gastrointestinal manifestations appear to be the main features of FMF, bloody diarrhea could also be considered an initial symptom of FMF.

Management of familial Mediterranean fever by colchicine does not normalize the altered profile of microbial long chain fatty acids in the human metabolome

In our previous works we established that in an autoinflammatory condition, familial Mediterranean fever (FMF), the gut microbial diversity is specifically restructured, which also results in the altered profiles of microbial long chain fatty acids (LCFAs) present in the systemic metabolome. The mainstream management of the disease is based on oral administration of colchicine to suppress clinical signs and extend remission periods and our aim was to determine whether this therapy normalizes the microbial LCFA profiles in the metabolome as well. Unexpectedly, the treatment does not normalize these profiles. Moreover, it results in the formation of new distinct microbial LCFA clusters, which are well separated from the corresponding values in healthy controls and FMF patients without the therapy. We hypothesize that the therapy alters the proinflammatory network specific for the disease, with the concomitant changes in gut microbiota and the corresponding microbial LCFAs in the metabolome.

The role of TNF-α and PAI-1 gene polymorphisms in familial Mediterranean fever

OBJECTIVES

Familial Mediterranean fever (FMF) is one of the most serious inherited inflammatory disorders among Jewish, Armenian, Turkish and Arab populations. The imbalance between pro- and anti-inflammatory cytokines may play a role in its etiology. We have investigated whether tumor necrosis factor-alpha (TNF-α) and plasminogen activator inhibitor 1 (PAI-1) gene polymorphisms are associated with FMF and evaluated the relationship between these polymorphisms and genotypic manifestation of FMF.

METHODS

We investigated single nucleotide polymorphisms of the TNF-α promoter at positions -308 G/A and the PAI-1 4G/5G gene polymorphism in peripheral blood leukocytes collected from 177 individuals with FMF with different genotype combinations. All of the polymorphisms of TNF-α and PAI-1 were detected by PCR and restriction fragment length polymorphism analysis.

RESULTS

There were no association between the TNF-α/308 genotypes and mutations in FMF. In contrast, the PAI-1 4G/5G gene polymorphism may have a significant effect in FMF disease.

CONCLUSIONS

Screening with PAI-1 gene polymorphism tests may be beneficial for tracing future FMF patients. However, further investigations are needed to reach a conclusion on the association between PAI-1 polymorphisms and FMF.

Familial Mediteranean fever with protein-losing enteropathy due to constrictive pericarditis

BACKGROUND

Constrictive pericarditis (CP) represents a rare cause of protein-losing enteropathy (PLE) resulting from intestinal lymphangiectasia (IL). In this report, we describe an 8-year-old Turkish boy with IL and PLE secondary to CP.

METHODS

The boy was introduced to our clinic due to bilateral pretibial edema and swelling of the eyelids caused by hypoproteinemia. Physical examination revealed a distended right jugular vein. Laboratory investigation revealed PLE with fecal concentration of alpha-1 antitripsin of 4.87 mg/g. Histopathologic examination of random biopsies obtained from the duodenum revealed markedly dilated lymphatics compatible with IL. Constrictive pericarditis was diagnosed by tagged cine cardiac magnetic resonance imaging.

RESULTS

Pericardiectomy was performed for the patient. Genetic analysis was done and heterozygous mutation E148Q was detected as a disease-causing Mediterranean fever (MEFV) mutation. Colchicine was started after the operation. Six months after the initiation of regular colchicine therapy, echocardiography revealed disappearance of CP.

CONCLUSION

This is the first reported case of PLE with a distended right jugular vein due to CP secondary to familial Mediterranean fever associated with E148Q heterozygosity in the MEFV gene.

Autoinflammatory diseases and cardiovascular manifestations

Abstract A host of clinical scenarios can be depicted in hereditary autoinflammatory diseases, and the cardiovascular system can also be involved especially in familial Mediterranean fever (FMF), caused by mutations in the MEFV gene, and tumour necrosis factor receptor-associated periodic syndrome (TRAPS), caused by mutations in the TNFRSF1A gene. Pericardial diseases are the most represented cardiovascular abnormalities, though the role of MEFV and TNFRSF1A in the initiation of heart involvement has not been demonstrated formally and will be discussed herein.

Enhanced exon 2 skipping caused by c.910G>A variant and alternative splicing of MEFV genes in two independent cases of familial Mediterranean fever

Most reported cases of familial Mediterranean fever (FMF) involve missense mutations of MEFV concentrated within exon 10. We experienced two independent pedigrees of a unique variant in the MEFV gene that might cause excessive exon 2 skipping due to enhanced alternative splicing. In this study, we tried to elucidate the molecular mechanism of the MEFV variant as a cause of the FMF phenotype. Peripheral blood was obtained from volunteers and two patients with homozygous c.910G>A variant of the MEFV gene. MEFV messenger RNA (mRNA) expression patterns in mononuclear cells and granulocytes were compared using forward and reverse primers from exons 1 and 3, respectively. Expression profiles of pyrin were examined by transfecting wild-type and variant MEFV genes into HEK293T cells. Expression of normal-sized mRNA was extremely reduced in these patients, whereas that of aberrant short mRNA, deleting exon 2 (Δex2), was significantly increased. Immunohistochemical and immunoblotting analyses revealed a truncated immunoreactive pyrin protein in cells transfected with Δex2 cDNA. The MEFV gene c.910G>A variant results in accelerated aberrant splicing with abnormal protein size, presumably leading to anomalous pyrin function. This is the first report to show that an MEFV variant other than missense mutation is responsible for the FMF phenotype.

Periodic fever syndromes in Eastern and Central European countries: results of a pediatric multinational survey

OBJECTIVE

To analyze the prevalence of diagnosed and suspected autoinflammatory diseases in Eastern and Central European (ECE) countries, with a particular interest on the diagnostic facilities in these countries.

METHODS

Two different strategies were used to collect data on patients with periodic fever syndromes from ECE countries- the Eurofever survey and collection of data with the structured questionnaire.

RESULTS

Data from 35 centers in 14 ECE countries were collected. All together there were 11 patients reported with genetically confirmed familial Mediterranean fever (FMF), 14 with mevalonate-kinase deficiency (MKD), 11 with tumor necrosis factor receptor associated periodic syndrome (TRAPS) and 4 with chronic infantile neurological cutaneous and articular syndrome (CINCA). Significantly higher numbers were reported for suspected cases which were not genetically tested. All together there were 49 suspected FMF patients reported, 24 MKD, 16 TRAPS, 7 CINCA and 2 suspected Muckle-Wells syndrome (MWS) patients.

CONCLUSIONS

The number of genetically confirmed patients with periodic fever syndromes in ECE countries is very low. In order to identify more patients in the future, it is important to organize educational programs for increasing the knowledge on these diseases and to establish a network for genetic testing of periodic fever syndromes in ECE countries.

Familial Mediterranean fever presenting as anti-cyclic citrullinated peptide antibody negative palindromic rheumatism

A 64-year-old Egyptian man who resides in the United States presented to the rheumatology clinic with 6 months history of episodic recurrent pauci--arthritis along with constitutional symptoms. His Mediterranean ancestry, anti-cyclic citrullinated peptide negativity, and cyclical palindromic rheumatism prompted an investigation for familial Mediterranean fever gene mutation. He was found to have heterozygous 694I gene mutation during MEFV analysis. He also met Liveneh 1 major and 1 minor criteria for the diagnosis of familial Mediterranean fever.

Common MEFV mutation analysis in 36 Iranian patients with familial Mediterranean fever: clinical and demographic significance

The aim of our study was to determine the spectrum of the 12 most common familial Mediterranean fever gene (MEFV) mutations in Iranian patients with heterogeneous ethnicity, using the familial Mediterranean fever (FMF) strip assay test. A total of 36 patients were diagnosed according to established clinical criteria. Genomic DNA from all patients was tested for 12 common mutations located in exon 2 (E148Q), 3 (P369S), 5 (F479L), 10 [M680I (G>C), M680I (G>A), I692del, M694V, M694I, K695R, V726A, A744S, R761H], respectively, using the FMF strip assay test. Of the 35 patients with mutations, ten were homozygote, 20 were compound heterozygote, and five were heterozygote. The most frequent genotype was M680I/M680I (6 patients, 16.7%). The most frequent mutation was M680I, followed by M694V, and V726A. The FMF strip assay test for common these 12 mutations was positive in 90.6% of alleles in this study, indicating that it appears to be an effective method for FMF mutation screening in Iranian patients.

Targeting IL-1beta in disease; the expanding role of NLRP3 inflammasome

NLRP3 inflammasome activation and IL-1beta secretion have recently emerged as a central mechanism in the pathogenesis of disease. Genetically defined syndromes like cryopyrin-associated periodic syndromes (CAPS, cryopyrinopathies) and familial Mediterranean fever (FMF) or diseases associated with NLRP3 activation by danger signals like gout, pseudogout, Alzheimer's disease or type 2 diabetes are included in this group of diseases. The contribution of anakinra, a recombinant, nonglycosylated human IL-1 receptor antagonist, in both the identification and treatment of such syndromes was considerable. Recently, rilonacept, a long-acting IL-1 receptor fusion protein, and canakinumab, a fully humanized anti-IL-1beta monoclonal antibody, have been developed, with the intention to further extent IL-1beta inhibition treatment strategies to a broader spectrum of disorders beyond the characterized autoinflammatory syndromes, offering a more favorable administration profile. On the other hand, the developed caspase-1 inhibitors, even though effective in experimental models, were not proven efficient in the treatment of inflammatory diseases.

Prevalence of known mutations in the MEFV gene in a population screening with high rate of carriers

The Familial Mediterranean Fever (FMF) shows an autosomal recessive pattern of inheritance and affects certain ethnic groups. Disease is caused by mutations in MEFV gene and more than 180 mutations have been defined in affected individuals. Current study aimed to determine the frequency-type of the mutations for MEFV gene in Sivas-middle Anatolian city. The cohort was composed of 3340 patients. MEFV gene mutations were studied by multiplex PCR based reverse hybridization stripAssay method. Patients' clinical features were; family history: 68%, erysipelas-like erythema: 17.6%, fever: 89.9%, abdominal pain: 84.2%, peritonitis: 90.2%, arthritis: 33%, pleuritis: 14.2%, parental consanguinity: 21.2%. Current results revealed that M694V is the most frequent mutation (43.12%), followed by E148Q (20.18), M680I(G/C) (15.00%) and V726A (11.32%). The study population has a high rate of carriers and the E148Q mutation frequency was found to be highest when compared to the other regions of Turkey and other Mediterranean groups.

A case of familial Mediterranean fever associated with compound heterozygosity for the pyrin variant L110P-E148Q/M680I in Japan

Familial Mediterranean fever (FMF) is an autosomal recessive disorder characterized by recurrent and self-limited fever attacks and serositis/arthritis. The M694V, M694I, M680I, V726A, and E148Q mutations in MEFV, the gene responsible for FMF, account for most FMF cases in Mediterranean populations. In Japan, M694I and E148Q are most frequently detected; M694V, M680I, and V726A have not been identified so far. We report the first case of FMF associated with M680I in Japan.

MEFV mutations in patients with Familial Mediterranean Fever from the Aegean region of Turkey

Familial Mediterranean Fever (FMF) which is frequently present in Mediterranean populations is caused by mutations in the MEFV gene. According to recent data, MEFV mutations are not the only cause of FMF, but these are major genetic determinants which cause FMF. It has also been suggested that there may be a number of other genes causing FMF. The MEFV gene is located at 16p13.3 and encodes a protein, pyrin/marenostrin. More than 70 disease associated mutations and totally 186 mutations and polymorphisms have been defined in affected individuals. We have retrospectively evaluated the molecular test results of 1,201 patients identified as having FMF clinical symptoms referred to the Molecular Genetics Laboratory of the Department of Medical Genetics, Faculty of Medicine, Ege University, Izmir/Turkey over the last 4 years. Patients were tested for 12 common mutations in the MEFV gene using a strip assay method (Innogenetics, Belgium). Out of the 1,201 patients tested (2,402 chromosomes) in the Aegean region in Turkey, 654 (54.45%) did not carry any mutations, among the 547 (45.55%) patients with mutations 246 patients were either homozygous (101) or compound heterozygous (145), 296 carried only one detected mutation, and five patients had three mutations. Allelic frequencies for the four most common mutations in the mutation positive groups were 47.60% (M694V), 16.75% (E148Q), 12.95% (V726A), 11.94% (M680I G/C).The remaining alleles (10.76%) showed rare mutations which were R761H, P369S, A744S, K695R, F479L, M694I. When the frequencies of mutations detected in our group were compared to the frequencies reported in the other regions of Turkey, an increase in V726A mutation frequency was observed. No patient showed a I692del mutation which is sometimes evident in other Mediterranean populations.