Population genetics of familial Mediterranean fever: a review

Single Nucleotide Polymorphisms of the MEFV Gene E148Q Are Highly Associated With Disease Phenotype in Crohn's Disease

BACKGROUND

Single nucleotide polymorphisms (SNPs) of the MEFV gene may modify inflammatory bowel disease (IBD) activity. The prevalence of MEFV gene SNPs in IBD patients and their involvement in IBD pathophysiology remains unclear.

METHODS

We analyzed 12 MEFV gene SNPs in peripheral leukocytes of Japanese IBD patients (Crohn's disease [CD]: 69 patients, ulcerative colitis: 32 patients) by polymerase chain reaction using next-generation DNA sequencing and evaluated their prevalence and association with the disease characteristics. Inflammasome activity and mature interleukin (IL)-1β and IL-18 production were evaluated in peripheral blood mononuclear cells obtained from CD patients stimulated with lipopolysaccharides and adenosine triphosphate, and compared between those with and without the E148Q SNP. COL1A1 and HSP47 gene expression was analyzed in CCD-18Co cells costimulated with IL-1β and other inflammatory cytokines.

RESULTS

The prevalence of MEFV gene SNPs in IBD patients was similar to that in the human gene database. E148Q was the most common SNP. Compared with CD patients without E148Q, those with E148Q had a significantly greater frequency of the stricture phenotype, and their peripheral blood mononuclear cells exhibited significantly higher IL-1β and IL-18 levels and higher caspase-1 activity. IL-1β and IL-17A synergistically increased COL1A1 and HSP47 gene expression.

CONCLUSIONS

MEFV gene SNPs, including E148Q, modify the behavior of CD. IL-1β and IL-18 are produced through enhanced caspase-1 activity in monocytes of CD patients with E148Q. IL-1β promotes gene expression of fibrosis-related genes by cooperating with IL-17A in myofibroblasts. Therefore, E148Q might be a disease-modifying gene associated with the fibrostenosis phenotype in CD patients.

Pyrin variant E148Q potentiates inflammasome activation and the effect of pathogenic mutations in cis

OBJECTIVE

The p.E148Q variant in pyrin is present in different populations at a frequency of up to 29%, and has been associated with diseases, including vasculitis and FMF. The pathogenicity of p.E148Q in FMF is unclear, even when observed in cis or in trans to a single, typically recessive, pathogenic mutation. We performed functional validation to determine whether p.E148Q increases the ability of pyrin to form an active inflammasome complex in cell lines.

METHODS

We interrogated the Australian Autoinflammatory Disease RegistrY (AADRY) to find candidate inheritance patterns for the p.E148Q variant in pyrin. Different pyrin variant combinations were tested in HEK293T cells stably expressing the adaptor protein apoptosis-associated speck-like (ASC), which were analysed by flow cytometry to visualize inflammasome formation, with and without stimulation by Clostridioides difficile toxin B (TcdB). Inflammasome-dependent cytokine secretion was also quantified by ELISA of supernatants from THP-1 cells transduced with lentiviral expression vectors.

RESULTS

In AADRY, we observed the p.E148Q allele in individuals with autoinflammatory diseases alone or in conjunction with other pyrin variants. Two FMF families harboured the allele p.E148Q-M694I in cis with dominant heritability. In vitro, p.E148Q pyrin could spontaneously potentiate inflammasome formation, with increased IL-1β and IL-18 secretion. p.E148Q in cis to classical FMF mutations provided significant potentiation of inflammasome formation.

CONCLUSION

The p.E148Q variant in pyrin potentiates inflammasome activation in vitro. In cis, this effect is additive to known pathogenic FMF mutations. In some families, this increased effect could explain why FMF segregates as an apparently dominant disease.

Patient Experiences and Challenges in the Management of Autoinflammatory Diseases-Data from the International FMF & AID Global Association Survey

BACKGROUND

Autoinflammatory diseases (AIDs) are rare, mostly genetic diseases that affect the innate immune system and are associated with inflammatory symptoms. Both paediatric and adult patients face daily challenges related to their disease, diagnosis and subsequent treatment. For this reason, a survey was developed in collaboration between the FMF & AID Global Association and the Erlangen Center for Periodic Systemic Autoinflammatory Diseases.

METHODS

The aim of the survey was to collect the personal assessment of affected patients with regard to their current status in terms of diagnostic timeframes, the interpretation of genetic tests, the number of misdiagnoses, and pain and fatigue despite treatment.

RESULTS

In total, data from 1043 AID patients (829 adults and 214 children/adolescents) from 52 countries were collected and analyzed. Familial Mediterranean fever (FMF) (521/50%) and Behçet's disease (311/30%) were the most frequently reported diseases. The average time to diagnosis was 3 years for children/adolescents and 14 years for adults. Prior to the diagnosis of autoinflammatory disease, patients received several misdiagnoses, including psychosomatic disorders. The vast majority of patients reported that genetic testing was available (92%), but only 69% were tested. A total of 217 patients reported that no increase in acute-phase reactants was detected during their disease episodes. The intensity of pain and fatigue was measured in AID patients and found to be high. A total of 88% of respondents received treatment again, while 8% reported no treatment.

CONCLUSIONS

AID patients, particularly adults, suffer from significant delays in diagnosis, misdiagnosis, and a variety of symptoms, including pain and fatigue. Based on the results presented, raising awareness of these diseases in the wider medical community is crucial to improving patient care and quality of life.

PFAPA syndrome in children

ABSTRACT

Periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) syndrome is, as the name implies, characterized by an extremely regular cycle of fevers that is accompanied by one or more other symptoms such as oral ulcers, pharyngitis, adenitis, tonsillitis, sore throat, cervical adenopathy, and headache. Originally known as Marshall syndrome, PFAPA is most commonly identified in children younger than age 5 years; however, adults may also present with the disease, though they may report additional symptoms. PFAPA is now understood to be a diagnosis of exclusion. Laboratory studies are typically unremarkable except for increases in acute phase reactants such as C-reactive protein. Treatment is primarily supportive and most frequently uses systemic steroids to suppress the inflammatory response. Acute flares are self-limited, and the syndrome typically resolves on its own as the child reaches age 7 or 8 years.

Genetic and Epigenetic Regulation of MEFV Gene and Their Impact on Clinical Outcome in Auto-Inflammatory Familial Mediterranean Fever Patients

Epigenetic modifications play a pivotal role in autoimmune/inflammatory disorders and could establish a bridge between personalized medicine and disease epidemiological contexts. We sought to investigate the role of epigenetic modifications beside genetic alterations in the MEFV gene in familial Mediterranean fever (FMF). The study comprised 63 FMF patients diagnosed according to the Tel Hashomer criteria: 37 (58.7%) colchicine-responders, 26 (41.3%) non-responders, and 19 matched healthy controls. MEFV mutations were detected using a CE/IVD-labeled 4-230 FMF strip assay. DNA methylation of MEFV gene exon 2 was measured using bisulfite modification and related to pyrin level, phenotypic picture, MEFV mutations, disease severity, serum amyloid A (SAA), CRP, ESR, disease severity, and colchicine response. Our results showed that FMF patients exhibited significantly higher methylation percentage (p < 0.001) and lower pyrin levels (p < 0.001) compared to the control. The MEFV gene M694I mutation was the most commonly reported mutation (p < 0.004). High methylation percentage of the MEFV exon 2 and low pyrin concentration were correlated with disease severity, high SAA, ESR levels, H-pylori, and renal calculi. In conclusion, this study highlights the relation between high methylation percentage, reduced pyrin level, and different biomarkers in FMF, which underscores their role in the pathogenesis of FMF and could be considered as potential therapeutic targets.

The effect of a 18 bp deletion/insertion variant of VEGF gene on the FMF development

Objective: Familial Mediterranean fever (FMF) is one of the most common inherited autoinflammatory diseases. Angiogenesis is a feature of inflammatory activation and part of pathogenic processes in autoimmune diseases. Therefore, this study aimed to investigate the role of the Vascular endothelial growth factor (VEGF) gene insertion/deletion (I/D) functional variant in FMF Turkish patients. Methods: MEFV gene mutations were detected in all patients. The FMF patients (N:105) and the healthy controls (N:100) were genotyped for the VEGF I/D variant using PCR followed by agarose gel electrophoresis. The results were statistically analyzed by calculating the odds ratios (OR) and their 95% confidence intervals (95% CI) using the χ²-tests. Results: The mean age of patients was 25.46 ± 10.09. Fifty-nine patients (56.2%) had two or more MEFV gene mutations. The most common MEFV mutation was M694V/M694V. The VEGF I/D variant genotype distribution exhibited a statistically significant difference between the patients and the controls. VEGF I/D genotype was higher in controls compared to patients, while D/D genotype was higher in patients compared to the controls (p = 0.003, p = 0.013, respectively). When we examined the clinical findings, joint pain was more common in patients with VEGF D/D and I/D genotypes compared to I/I genotype (p = 0.043). Although not statistically significant, the most common genotype in patients with two or more MEFV mutations was VEGF D/D (28.6%). Conclusion: The results provided evidence supporting that the D/D genotype of the VEGF I/D variant is associated with an increased risk of FMF in a group of Turkish populations.

M680I/M694V Heterozygous Mutation in Early Onset Familial Mediterranean Fever

Familial Mediterranean fever (FMF) is a hereditary autoinflammatory disorder affecting individuals with biallelic pathogenic mutations in the MEFV gene. The disease is characterized by recurrent attacks of fever and serosal inflammation as manifested by abdominal and chest pain. This case report presents an FMF case with a 3-year history of pain crises consisting of severe abdominal pain and fever, lasting up to 72 h. Genetic investigation identified an uncommon heterozygous mutation in the MEFV gene. This mutation is associated with a more severe phenotype of FMF and may lead to an early onset of the disease.

Current and future advances in genetic testing in systemic autoinflammatory diseases

Systemic autoinflammatory diseases (SAIDs) are a group of inflammatory disorders caused by dysregulation in the innate immune system that leads to enhanced immune responses. The clinical diagnosis of SAIDs can be difficult since individually these are rare diseases with considerable phenotypic overlap. Most SAIDs have a strong genetic background, but environmental and epigenetic influences can modulate the clinical phenotype. Molecular diagnosis has become essential for confirmation of clinical diagnosis. To date there are over 30 genes and a variety of modes of inheritance that have been associated with monogenic SAIDs. Mutations in the same gene can lead to very distinct phenotypes and can have different inheritance patterns. In addition, somatic mutations have been reported in several of these conditions. New genetic testing methods and databases are being developed to facilitate the molecular diagnosis of SAIDs, which is of major importance for treatment, prognosis and genetic counselling. The aim of this review is to summarize the latest advances in genetic testing for SAIDs and discuss potential obstacles that might arise during the molecular diagnosis of SAIDs.

Hints for Genetic and Clinical Differentiation of Adult-Onset Monogenic Autoinflammatory Diseases

Monogenic autoinflammatory diseases (mAIDs) are inherited errors of innate immunity characterized by systemic inflammation recurring with variable frequency and involving the skin, serosal membranes, synovial membranes, joints, the gastrointestinal tube, and/or the central nervous system, with reactive amyloidosis as a potential severe long-term consequence. Although individually uncommon, all mAIDs set up an emerging chapter of internal medicine: recent findings have modified our knowledge regarding mAID pathophysiology and clarified that protean inflammatory symptoms can be variably associated with periodic fevers, depicting multiple specific conditions which usually start in childhood, such as familial Mediterranean fever, tumor necrosis factor receptor-associated periodic syndrome, cryopyrin-associated periodic syndrome, and mevalonate kinase deficiency. There are no evidence-based studies to establish which potential genotype analysis is the most appropriate in adult patients with clinical phenotypes suggestive of mAIDs. This review discusses genetic and clinical hints for an ideal diagnostic approach to mAIDs in adult patients, as their early identification is essential to prompt effective treatment and improve quality of life, and also highlights the most recent developments in the diagnostic work-up for the most frequent hereditary periodic febrile syndromes worldwide.

Familial Mediterranean Fever: Assessing the Overall Clinical Impact and Formulating Treatment Plans

Recurrent self-limited attacks of fever and short-lived inflammation in the serosal membranes, joints, and skin are the leading features of familial Mediterranean fever (FMF), the most common autoinflammatory disorder in the world, transmitted as autosomal recessive trait caused by MEFV gene mutations. Their consequence is an abnormal function of pyrin, a natural repressor of inflammation, apoptosis, and release of cytokines. FMF-related mutant pyrins are hypophosphorylated following RhoA GTPases’ impaired activity and show a propensity to relapsing uncontrolled systemic inflammation with inappropriate response to inflammatory stimuli and leukocyte spread to serosal membranes, joints or skin. Typical FMF phenotype 1 consists of brief episodes of inflammation and serositis, synovitis, and/or erysipelas-like eruption, whereas phenotype 2 is defined by reactive amyloid-associated (AA) amyloidosis, which is the most ominous complication of FMF, in otherwise asymptomatic individuals.

Furthermore, FMF phenotype 3 is referred to the presence of two MEFV mutations with neither clinical signs of FMF nor AA amyloidosis. The influence of epigenetic and/or environmental factors can contribute to the variable penetrance and phenotypic heterogeneity of FMF. Colchicine, a tricyclic alkaloid with anti-microtubule and anti-inflammatory properties, is the bedrock of FMF management: daily administration of colchicine prevents the recurrence of FMF attacks and the development of secondary AA amyloidosis. Many recent studies have also shown that anti-interleukin-1 treatment is the best therapeutic option for FMF patients nonresponsive or intolerant to colchicine. This review aims to catch readers’ attention to the clinical diversity of phenotypes, differential diagnosis, and management of patients with FMF.

Bile acid analogues are activators of pyrin inflammasome

Bile acids are critical metabolites in the gastrointestinal tract and contribute to maintaining intestinal immune homeostasis through cross-talk with the gut microbiota. The conversion of bile acids by the gut microbiome is now recognized as a factor affecting both host metabolism and immune responses, but its physiological roles remain unclear. We conducted a screen for microbiome metabolites that would function as inflammasome activators and herein report the identification of 12-oxo-lithocholic acid (BAA485), a potential microbiome-derived bile acid metabolite. We demonstrate that the more potent analogue 11-oxo-12S-hydroxylithocholic acid methyl ester (BAA473) can induce secretion of interleukin-18 (IL-18) through activation of the inflammasome in both myeloid and intestinal epithelial cells. Using a genome-wide CRISPR screen with compound induced pyroptosis in THP-1 cells, we identified that inflammasome activation by BAA473 is pyrin-dependent (MEFV). To our knowledge, the bile acid analogues BAA485 and BAA473 are the first small molecule activators of the pyrin inflammasome. We surmise that pyrin inflammasome activation through microbiota-modified bile acid metabolites such as BAA473 and BAA485 plays a role in gut microbiota regulated intestinal immune response. The discovery of these two bioactive compounds may help to further unveil the importance of pyrin in gut homeostasis and autoimmune diseases.

The Broad-Ranging Panorama of Systemic Autoinflammatory Disorders with Specific Focus on Acute Painful Symptoms and Hematologic Manifestations in Children

Systemic autoinflammatory disorders (SAIDs) are inherited defects of innate immunity characterized by recurrent sterile inflammatory attacks involving skin, joints, serosal membranes, gastrointestinal tube, and other tissues, which recur with variable rhythmicity and display reactive amyloidosis as a potential long-term complication. Dysregulated inflammasome activity leading to overproduction of many proinflammatory cytokines, such as interleukin-1 (IL-1), and delayed shutdown of inflammation are considered crucial pathogenic keys in the vast majority of SAIDs. Progress of cellular biology has partially clarified the mechanisms behind monogenic SAIDs, such as familial Mediterranean fever, tumor necrosis factor receptor-associated periodic syndrome, cryopyrin-associated periodic syndrome, mevalonate kinase deficiency, hereditary pyogenic diseases, idiopathic granulomatous diseases and defects of the ubiquitin-proteasome pathway. Whereas, little is clarified for the polygenic SAIDs, such as periodic fever, aphthous stomatitis, pharyngitis, and cervical adenopathy (PFAPA) syndrome. The puzzle of symptomatic febrile attacks recurring over time in children requires evaluating the mixture of clinical data, inflammatory parameters in different disease phases, the therapeutic efficacy of specific drugs such as colchicine, corticosteroids or IL-1 antagonists, and genotype analysis in selected cases. The long-term history of periodic fevers should also need to rule out chronic infections and malignancies. This review is conceived as a practical template for proper classification of children with recurring fevers and includes tips useful for the diagnostic approach to SAIDs, focusing on the specific acute painful symptoms and hematologic manifestations encountered in childhood.

Familial Mediterranean fever: overview of pathogenesis, clinical features and management

Familial Mediterranean fever (FMF) is the most common monogenic autoinflammatory disease, and is characterized by recurrent attacks of fever and polyserositis. It is associated with mutations in the MEFV gene encoding pyrin, which result in inflammasome activation and the uncontrolled production of IL-1β. FMF mainly affects individuals originating from the Mediterranean basin; however, a Japanese nationwide survey demonstrated that FMF is not uncommon in Japan. The survey also indicated that Japanese FMF patients are clinically or genetically distinct from Mediterranean FMF patients, suggesting a genotype-phenotype correlation. In Japanese patients with FMF, MEFV exon 10 mutations are associated with the more typical FMF phenotype. Conversely, Japanese FMF patients with mutations in MEFV exons 2 or 3 present with an atypical FMF phenotype. Colchicine is the mainstay of FMF treatment, and its regular use prevents febrile attacks and decreases the long-term risk of AA amyloidosis. However, a minority of FMF patients are colchicine-resistant, and anti-IL-1 treatment has proven beneficial in suppressing inflammation in these patients. Although Japanese FMF patients may develop less severe disease compared with Mediterranean FMF patients, they should nevertheless be treated early to prevent recurrent attacks and the subsequent development of AA amyloidosis.

Is colchicine more effective to prevent periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis episodes in Mediterranean fever gene variants?

BACKGROUND

Periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis (PFAPA) syndrome is the most frequent repetitive fever syndrome in childhood. It is characterized by fever episodes lasting for approximately 3-6 days, once every 3-8 weeks.

METHODS

Clinical and laboratory data for PFAPA syndrome patients between January 2010 and December 2014 followed up at a tertiary pediatric care hospital were reviewed.

RESULTS

Four hundred children (256 male, 144 female; mean age at diagnosis, 4.2 ± 2.2 years), were enrolled in the study. During the episodes, mean leukocyte number was high (12 725/mm³ ) with predominant neutrophils. The mean number of monocytes was 1256/mm³ , and 90.2% had monocytosis. Serum amyloid A and C-reactive protein were high in 84.6% and in 77.8% of the patients, respectively. Mediterranean fever (MEFV) gene heterozygous mutation was identified in 57 of the 231 patients (24.7%) in whom genetic analysis had been performed. The most frequent mutation was heterozygous M694V (10%, n = 23). Extension of between-episode interval following prophylaxis was noted in 85% of those on regular colchicine treatment (n = 303). In the colchicine group, between-episode interval was prolonged from 18.8 ± 7.9 days (before colchicine treatment) to 49.5 ± 17.6 days on prophylactic colchicine therapy; also, prophylactic treatment was more effective in reducing episode frequency in patients with MEFV gene variant (n = 54, 96%) than in those without (n = 122, 80%; P = 0.003).

CONCLUSIONS

This study has involved the largest number of PFAPA syndrome patients in the literature. It is particularly important to assess and to demonstrate the high rate of response to colchicine prophylaxis in PFAPA syndrome patients, especially those with MEFV variant. On blood screening, neutrophilia associated with monocytosis and low procalcitonin could contribute to diagnosis.

Bone Mineral Density in Egyptian Children with Familial Mediterranean Fever

BACKGROUND

Familial Mediterranean fever (FMF) has episodic or subclinical inflammation that may lead to a decrease in bone mineral density (BMD). The objective of this study was to assess BMD in Egyptian children with FMF on genetic basis.

METHODS

A cross sectional study included 45 FMF patients and 25 control children of both sexes in the age range between 3-16 years old. The patients were reclassified into two groups, namely group I(A) with 23 cases using colchicine for 1 month or less, and group I(B) with 22 cases using colchicine for more than 6 months. For both the patients and control groups, MEFV mutations were defined using molecular genetics technique and BMD was measured by DXA at the proximal femur and lumbar spines.

RESULTS

Four frequent gene mutations were found in the patient group E148Q (35.6%), V726A (33.3%), M680I (28.9%), and M694V (2.2%). There were also four heterozygous gene mutations in 40% of the control children. Patients receiving colchicine treatment for less than 1 month had highly significant lower values of BMD at the femur and lumbar spines than the control children (P=0.007, P<0.001). Patients receiving colchicine treatment for more than 6 months had improved values of BMD at femur compared with the control, but there were still significant differences between them in lumbar spine (P=0.036). There were insignificant effect of gene mutation type on BMD and the risk of osteopenia among the patients.

CONCLUSION

FMF had a significant effect on BMD. However, regular use of colchicine treatment improves this effect mainly at the femur.

A case of a ten-year old girl with dominantly inherited Familial Mediterranean fever in Republic of Macedonia

The Familial Mediterranean fever (FMF, MIM249100) is an autoimflammatory genetic disease characterized with recurrent painful attacks in the abdomen, chest or joints, usually accompanied with high body temperature. It is classically inherited in an autosomal recessive manner. It is associated with mutations of the MEFV gene, coding for the protein pyrin. More than 140 mutations of the MEFV gene are defined worldwide. Despite the progress in establishing reliable tests practical for routine use, as much as 20% of the patients with FMF remain without a detectable mutation in the MEFV gene. This is the main reason why the diagnosis of FMF remains still a clinical one, according to Tel Hashomer criteria. A 10-year old girl admitted to the Clinic of Pediatrics at the Faculty of Medicine in Skopje for unexplained fever. After numerous laboratory analyses and specialist consultations were done, genetic testing for FMF was requested. The presence of an heterozygous mutation E148Q was confirmed at the Institute for Immunobiology and Human Genetics using a PCR based, reverse hybridization method. Administration of colchicine, the therapy of choice, in a dose of 1.5 mg/day, lead to complete resolution of the symptoms within some days following commencement. Although the disease is classically inherited in a recessive manner, some atypical cases of autosomal dominant inheritance are described. Our patient may be another example supporting the unusual dominant inheritance, since the heterozygous state for the E148Q mutation was the only positive finding in the genotyping of the 12 most frequent MEFV mutations.

Clinical evaluation of R202Q alteration of MEFV genes in Turkish children

To date, over 200 alterations have been reported in Mediterranean fever (MEFV) genes, but it is not clear whether all these alterations are disease-causing mutations. This study aims to evaluate the clinical features of the children with R202Q alteration. The medical records of children with R202Q alteration were reviewed retrospectively. A total of 225 children, with 113 males, were included. Fifty-five patients were heterozygous, 30 patients were homozygous for R202Q, and 140 patients were compound heterozygous. Classical familial Mediterranean fever (FMF) phenotype was present in 113 patients: 2 heterozygous and 7 homozygous R202Q, 46 double homozygous R202Q and M694V, and 58 compound heterozygous. The main clinical characteristics of the patients were abdominal pain in 71.5 %, fever in 37.7 %, arthralgia/myalgia in 30.2 %, arthritis in 10.2 %, chest pain in 14.6 % and erysipelas-like erythema in 13.3 %. The frequency of abdominal pain was significantly lower in patients with homozygous R202Q alteration (p = 0.021), whereas patients with heterozygous R202Q mutations, though not statistically significant, had a higher frequency of arthralgia/myalgia (40.0 %, p = 0.05). R202Q alteration of the MEFV gene leads to symptoms consistent with FMF in some cases. This alteration may be associated with a mild phenotype and shows phenotypic differences other than the common MEFV mutations.

An unusual cause of peritonitis in a deployed environment

Acute abdominal pain is a common presenting complaint to both primary and secondary care, and is a frequent cause of hospital admission among deployed personnel. Identification of generalised peritonism on abdominal examination is a classical indicator of intra-abdominal pathology that may warrant exploratory laparotomy. Negative findings at laparotomy should serve as a diagnostic prompt to consider other non-surgical mimics of an acute abdomen.

Association between MEFV gene mutations and recurrent aphthous stomatitis in a cohort of Turkish patients

Recurrent aphthous stomatitis (RAS) has a multifactorial etiopathogenesis, an interaction between predisposing factors and/or systemic conditions and immunological components in genetically predisposed subjects. The Mediterranean fever (MEFV) gene has already been identified as being responsible for familial Mediterranean fever. Because the association between MEFV gene mutations and Behçet's disease has been reported before in several studies, we considered that the role of MEFV gene mutations should be studied in patients with RAS, because of the clinical similarities of both diseases. The aim of this study was to explore the frequency and clinical significance of MEFV gene mutations in a cohort of Turkish patients with RAS. The study population comprised 100 unrelated patients with a clinical diagnosis of RAS and 156 healthy controls. Genomic DNA was isolated and genotyped using polymerase chain reaction and restriction fragment length polymorphism for the four MEFV gene mutations (M694V, M680I, V726A and E148Q). There were statistically significant differences of the MEFV gene mutation carrier rates and allele frequencies between RAS patients and healthy controls (P = 0.042, odds ratio [OR] = 1.9, 95% confidence interval [CI] = 1.01-3.41; and P = 0.039, OR = 1.8, 95% CI = 1.02-3.14, respectively). Even if it is not statistically significant, the E148Q allele frequency was higher in patients with RAS than the control group. A statistically significant increased prevalence of MEFV variants in RAS patients was found. This is the first study to report that missense mutations of MEFV is associated with RAS in the Turkish population.

Plasminogen activator inhibitor-1 gene polymorphism in Iranian Azeri Turkish patients with FMF disease and its association with amyloidosis

Familial Mediterranean fever (FMF) is an autosomal recessive disorder characterized by intermittent episodes of fever with serositis, arthritis, or eriseplemya. Plasminogen activator inhibitor 1 (PAI-1) is a key element in the inhibition of fibrinolysis by inactivating tissue-type and urokinase-type plasminogen activators. We evaluated the association of PAI-1 -675 4G/5G polymorphism with the severity of FMF disease. For this purpose, 89 FMF patients with M694V homozygous mutation and 95 healthy controls from Iranian Azeri Turks were selected. Detection of this polymorphism was performed by polymerase chain reaction using allele-specific primers. No significant association was found between patients and control group. However, these data showed that FMF patients with M694V homozygous mutation carrying 4G/4G genotype have a reduced risk for development of pleuritis (odds ratios (OR) 0.36; 95 % confidence intervals (CI) 0.5-0.85; P value = 0.007) compared with 5G/5G homozygotes who have increased risk for development of amyloidosis (OR = 2.46; 95 %CI = 1.29-4.72; P value = 0.001), pleuritis (OR = 2.55; 95 %CI = 1.31-4.99; P value = 0.001), and fever (OR = 4.68; 95 %CI = 2.04-10.96; P value = 0.000). Furthermore, the allelic frequency of the 4G among the patients with pleuritis was significantly low (OR = 0.5, 95 % CI = 0.27-0.92, P value = 0.008).

CONCLUSION

Our data suggest a protective role for the 4G allele against pleuritis in FMF patients with M694V homozygous mutation in this cohort. More evaluation of this polymorphism may be important and require further studies.

Clinical and biochemical landmarks in systemic autoinflammatory diseases

Systemic autoinflammatory diseases are a group of inherited disorders of the innate immune system characterized by seemingly unprovoked inflammation recurring at variable intervals and involving skin, serosal membranes, joints, and gastrointestinal apparatus, with reactive amyloidosis as a possible severe long-term complication. Recent advances in genetics and molecular biology have improved our understanding of the pathogenesis of these diseases, including familial Mediterranean fever, mevalonate kinase deficiency syndrome, tumor necrosis factor receptor-associated periodic syndrome, cryopyrin-associated periodic syndromes, and hereditary pyogenic and granulomatous disorders: the vast majority of these conditions are related to the activation of the interleukin-1 pathway, which results in (or from?) a common unifying pathogenetic mechanism. Their diagnostic identification derives from the combination of clinical data, evaluation of acute phase reactants, clinical efficacy in response to specific drugs, and recognition of specific mutations in the relevant genes, although genetic tests may be unconstructive in some cases. This review will discuss clinical and laboratory clues useful for a diagnostic approach to systemic autoinflammatory diseases.

Significance of MEFV gene R202Q polymorphism in Turkish familial Mediterranean fever patients

OBJECTIVE

Familial Mediterranean fever (FMF) is an autosomal recessive disorder characterized by recurrent attacks of fever and inflammation in the peritoneum, synovium, or pleura, accompanied by pain. The disease is associated with mutations in the Mediterranean fever (MEFV) gene, which encodes for the pyrin protein. The aim of this study was to explore the frequency and clinical significance of the R202Q (c.605G>A) polymorphism in exon 2 of the MEFV gene in a cohort of Turkish patients with FMF.

METHODS

The study included 191 patients with FMF and 150 healthy controls. Genomic DNA was isolated and genotyped using polymerase chain reaction (PCR)-based restriction fragment length polymorphism (RFLP) assay for the MEFV gene R202Q polymorphism.

RESULTS

The genotype and allele frequencies of R202Q polymorphism showed a statistically significant difference between FMF patients and controls (p<0.0001 and p=0.0004, respectively) and especially the homozygous AA genotype was significantly higher in FMF patients than healthy controls (p=0.0002; odds ratio=6.27; 95% CI=2.1-18.3). However no significant association was observed between clinical and demographic features of FMF patients and R202Qpolymorphism.

CONCLUSION

The results of this study showed that there was a high association between MEFV gene R202Q polymorphism and FMF. R202Q polymorphism should be included in routine molecular diagnosis of FMF patients.

A molecular analysis of familial Mediterranean fever disease in a cohort of Turkish patients

BACKGROUND AND OBJECTIVES

Familial Mediterranean fever (FMF) is an autosomal recessive disorder caused by mutations in MEFV gene, which encodes pyrin. FMF is especially prevalent among Turks, Armenians, non-Ashkenazi Jews, and Arabs. The aim of this study was to determine the frequency and spectrum of 12 MEFV mutations of these patients and any genotype-phenotype correlation in this large Turkish group.

DESIGN AND SETTING

A retrospective study at Erciyes University Medical Faculty, from January 2007 to June 2009.

PATIENTS AND METHODS

We enrolled 446 Turkish FMF patients and identified the known 12 MEFV mutations with clinical investigations. DNA was amplified by PCR and subjected to reverse hybridization for the detection of MEFV gene mutations.

RESULTS

Among the 446 patients, 103 (46.6%) had a heterozygous genotype, 44 (19.9%) had a homozygous genotype, and 74 (33.49%) had a compound heterozygous genotype. The most common mutation detected was heterozygote M694V (46/221). Of the included 446 patients, 218 (48.87%) were male and 228 (51.12%) were female. High parental consanguinity rates affect FMF development. The clinical spectrum varied with different mutation profiles.

CONCLUSIONS

This study plays an important role in detecting the distribution of MEFV mutations and determining clinical approaches among Turk FMF patients. Also, we seemed to detect a distinctive clinical picture, specifically a lower frequency of amyloidosis.

Logical Gene Ontology Annotations (GOAL): exploring gene ontology annotations with OWL

MOTIVATION

Ontologies such as the Gene Ontology (GO) and their use in annotations make cross species comparisons of genes possible, along with a wide range of other analytical activities. The bio-ontologies community, in particular the Open Biomedical Ontologies (OBO) community, have provided many other ontologies and an increasingly large volume of annotations of gene products that can be exploited in query and analysis. As many annotations with different ontologies centre upon gene products, there is a possibility to explore gene products through multiple ontological perspectives at the same time. Questions could be asked that link a gene product's function, process, cellular location, phenotype and disease. Current tools, such as AmiGO, allow exploration of genes based on their GO annotations, but not through multiple ontological perspectives. In addition, the semantics of these ontology's representations should be able to, through automated reasoning, afford richer query opportunities of the gene product annotations than is currently possible.

RESULTS

To do this multi-perspective, richer querying of gene product annotations, we have created the Logical Gene Ontology, or GOAL ontology, in OWL that combines the Gene Ontology, Human Disease Ontology and the Mammalian Phenotype Ontology, together with classes that represent the annotations with these ontologies for mouse gene products. Each mouse gene product is represented as a class, with the appropriate relationships to the GO aspects, phenotype and disease with which it has been annotated. We then use defined classes to query these protein classes through automated reasoning, and to build a complex hierarchy of gene products. We have presented this through a Web interface that allows arbitrary queries to be constructed and the results displayed.

CONCLUSION

This standard use of OWL affords a rich interaction with Gene Ontology, Human Disease Ontology and Mammalian Phenotype Ontology annotations for the mouse, to give a fine partitioning of the gene products in the GOAL ontology. OWL in combination with automated reasoning can be effectively used to query across ontologies to ask biologically rich questions. We have demonstrated that automated reasoning can be used to deliver practical on-line querying support for the ontology annotations available for the mouse.

AVAILABILITY

The GOAL Web page is to be found at http://owl.cs.manchester.ac.uk/goal.

The first case of familial Mediterranean fever associated with renal amyloidosis in Korea

Familial Mediterranean fever (FMF) is an auto-inflammatory disease characterized by periodic episodes of fever and recurrent polyserositis. It is caused by a dysfunction of pyrin (or marenostrin) as a result of a mutation within the MEFV gene. It occurs mostly in individuals of Mediterranean origin; however, it has also been reported in non-Mediterranean populations. In this report, we describe the first case of FMF in a Korean child. As eight-year-old boy presented recurrent febrile attacks from an unknown cause, an acute scrotum and renal amyloidosis. He also showed splenomegaly, lymphadenopathy, pleural effusion, ascites and elevated acute phase reactants. After MEFV gene analysis, he was diagnosed as FMF combined with amyloidosis.

Common Familial Mediterranean Fever gene mutations in a Turkish cohort

Familial Mediterranean Fever (FMF) is an autosomal recessive autoinflammatory disorder with the responsible gene of MEFV which primarily affects Jewish, Armenian, Turkish and Arab populations. The FMF gene (MEFV) has recently been cloned to chromosome 16 p, which encodes pyrin. In the present study, we enrolled 2,067 unrelated patients with the suspicion of FMF in Middle Anatolia between the years 2006-2009 and identified the 12 MEFV mutations. DNA was amplified by PCR and subjected to reverse hybridization for the detection of MEFV gene mutations. Among the 2,067 patients, 866 (41.9%) were males and 1,201 (58.1%) were females. The mutations were homozygous in 176 (16.85%) patients, compound heterozygous in 314 (30.1%) patients, heterozygous in 546 (52.25%) patients and the other forms of mutations were found in 8 patients (0.76%). No mutation was detected in 1,023 (49.5%) patients. The most frequent mutations were M694V, M680I (G/C), E148Q and V726A. We could not find any significant differences between the two common mutations according to the gender. The high incidence of MEFV gene mutations in the Turkish population indicated that newborn screening may be discussed in the future. Because of the ethnic origin of Anatolia, larger serial analyses are necessary to investigate the rate and coexistence of these mutations.

Evaluation of common mutations in the Mediterranean fever gene in Multiple Sclerosis patients: is it a susceptibility gene?

PURPOSE

Multiple Sclerosis (MS) is a disease of the central nervous system characterized by multiple areas of inflammation and demyelination in the white matter of the brain and spinal cord. MEFV gene, which is the main factor in familial Mediterranean fever, is an intracellular regulator of inflammation. This study was designed to determine if known mutations in pyrin domain of MEFV gene are involved in MS and associated with MS morbidity.

METHODS

Fifty-three patients with MS and 66 healthy subjects, who were all Turkish, were included in this study. Five pyrin gene mutations (E148Q, M680I, M694V, M694I and V726A) were detected in the patients and controls by using the PRONTO FMF Basic Kit according to the manufacturer's instructions.

RESULTS

Pyrin gene mutations were found in 20 of the 53 MS patients (38%) and in seven of the 66 healthy subjects (11%). The frequency of total pyrin domain mutations was significantly higher in the MS patients than in the healthy subjects (p<0.0001). The frequencies of M694V, E148Q and V726A mutations were significantly higher in the patients than in the healthy subjects (p=0.02, p=0.013, p=0.004 respectively). The mean time to reach EDSS score 3.0 was earlier in the patients with MEFV gene mutation (p=0.02) and the relapse rate was slightly higher among the MS patients carrying MEFV gene mutation (p=0.04).

CONCLUSION

The results of this study supported the hypothesis that MS patients with MEFV mutation seem to have the susceptibility to develop a more progressive disease. Moreover, these data suggest that MEFV mutations may increase the risk of MS development.

Current perspectives on familial Mediterranean fever

PURPOSE OF REVIEW

The gene responsible for familial Mediterranean Fever (FMF), MEditerranean FeVer (MEFV), was identified two decades ago; however, only recent studies have shed light on its pathogenesis. This review focuses on recent studies that have led us to more fully understand FMF pathogenesis.

RECENT FINDINGS

The vast majority of FMF-associated mutations are located in the B30.2 (SPRY) domain, which functions as a ligand binding or a signal transduction domain, at the carboxy terminus of the protein. As a result, B30.2 mutations may lead to postponed apoptosis and inflammation due to the reduced ability of pyrin to control interleukin-1beta (IL-1beta) activation. Development of AA amyloidosis is rare in FMF patients without amyloidogenic single nucleotide polymorphisms (SNPs) (713T allele) of the SAA1 gene. High macrophage inflammatory protein-1alpha levels during FMF attacks might be responsible for the enhancement of T-cell mediated immunity in FMF. IL-1beta-511 (C/T), IL-1beta+3953 (C/T) and IL-1Ra VNTR polymorphisms were not associated with the development of amyloid in FMF patients.

SUMMARY

Future studies should focus on defining the impact of MEFV and other mutations on the pathological course of FMF, and to understand the exact pathophysiology of those patients who are unresponsive to colchicine, which may help to develop novel therapeutic options for the management and improvement of prognosis.

Isolated populations and complex disease gene identification

Isolated populations can be useful for the identification of genes underlying common complex diseases.

The utility of genetically isolated populations (population isolates) in the mapping and identification of genes is not only limited to the study of rare diseases; isolated populations also provide a useful resource for studies aimed at improved understanding of the biology underlying common diseases and their component traits. Well characterized human populations provide excellent study samples for many different genetic investigations, ranging from genome-wide association studies to the characterization of interactions between genes and the environment.