Association of the MEFV gene variations with inflammatory bowel disease in Turkey

The Influence of Coexisting Familial Mediterranean Fever on Crohn's Disease: Data From an FMF Endemic Area

GOAL

The goal of this study was to evaluate the impact of coexisting familial Mediterranean fever (FMF) on Crohn's disease (CD) patients' phenotype and disease course in an endemic region for FMF.

BACKGROUND

CD and FMF are inflammatory diseases characterized by recurrent abdominal pain and fever attacks. The impact of coexisting FMF on CD patients' phenotype and disease course is currently unknown.

MATERIALS AND METHODS

We reviewed the medical records of 210 adult CD patients who were regularly followed up at a tertiary gastroenterology clinic between November 2006 and April 2018. The patients were divided into FMF positive (CD-FMF) and FMF negative (CD-control) groups. The severity of CD was assessed by the rate of hospitalization because of CD, the need for biological therapy, and whether surgery was performed for CD.

RESULTS

Eight (3.8%) of 210 CD patients have concomitant FMF, which is 35 to 40 times higher than expected in an endemic region for FMF. Baseline demographic parameters, location/behavior of the CD, and initial therapeutic regimens were similar between the 2 groups. The prevalence of peripheral arthritis was significantly higher in CD-FMF group (37.5% vs. 10.4%, respectively, P =0.04). A significantly greater proportion of the CD-FMF patients had received biological therapy (50% vs. 11.9%; P =0.012). Steroid dependence and CD-related hospitalization rates in the CD-FMF group were relatively higher but were not statistically significant (37.5% vs. 15.3 and 62.5% vs. 41.1%).

CONCLUSIONS

Our findings indicate that the disease course of CD tends to be more severe in patients with coexisting FMF.

Next generation sequencing (NGS)-based approach to diagnosing Algerian patients with suspected inborn errors of immunity (IEIs)

The advent of next-generation sequencing (NGS) technologies has greatly expanded our understanding of both the clinical spectra and genetic landscape of inborn errors of immunity (IEIs). Endogamous populations may be enriched for unique, ancestry-specific disease-causing variants, a consideration that significantly impacts molecular testing and analysis strategies. Herein, we report on the application of a 2-step NGS-based testing approach beginning with targeted gene panels (TGPs) tailored to specific IEI subtypes and reflexing to whole exome sequencing (WES) if negative for Northwest Algerian patients with suspected IEIs. Our overall diagnostic yield of 57% is comparable to others broadly applying short-read NGS to IEI detection, but data from our localized cohort show some similarities and differences from NGS studies performed on larger regional IEI cohorts. This suggests the importance of tailoring diagnostic strategies to local demographics and needs, but also highlights ongoing concerns inherent to the application of genomics for clinical IEI diagnostics.

Behçet disease, familial Mediterranean fever and MEFV variations: More than just an association

Behçet disease (BD) and familial Mediterranean fever (FMF) are two inflammatory disorders that share many features including historical background, ethnical distribution and inflammatory characteristics. Several studies suggested that BD and FMF might occur in the same individual more commonly than expected. Additionally, the pathogenic MEFV gene variants, especially p.Met694Val, activating the inflammasome complex have been shown to increase the risk for BD in regions where both FMF and BD are prevalent. Whether these variants are associated with certain disease subtypes and whether they may help in the planning of treatment need to be explored. This review provides a recent overview of the plausible association between FMF and BD and the role of MEFV variants in the pathogenesis of BD.

Vasculitis and familial Mediterranean fever: Description of 22 French adults from the juvenile inflammatory rheumatism cohort

Objective

The frequency of vasculitis may be increased in patients with Familial Mediterranean Fever (FMF), according to several studies. Our aim was to assess the characteristics of French adult patients with both diseases.

Methods

Patients with vasculitis were selected from patients followed for FMF in the French JIR-cohort.

Results

Twenty-two patients were included [polyarteritis nodosa (PAN) n = 10, IgA vasculitis n = 8, unclassified vasculitis n = 2, granulomatosis with polyangiitis n = 1, and microscopic polyangiitis n = 1]. Pathogenic mutations in exon 10 were found in all 21 patients (96%) for which MEFV testing results were available, and 18 (82%) had two pathogenic mutations. Histology showed vasculitis in 59% of patients. Most patients with FMF-associated PAN were HBV-negative and had an inactive FMF before PAN onset, and 40% had a peri-renal or central nervous system bleeding. Most patients with FMF-associated IgA vasculitis had an active FMF before vasculitis onset, and 25% had digestive bleeding. Both patients with unclassified vasculitis had ischemic and/or hemorrhagic complications.

Conclusion

This study confirms the predominance of PAN and IgA vasculitis in patients with FMF and the high frequency of bleeding in FMF-associated PAN. FMF should be considered in case of persistent symptoms and/or inflammatory syndrome despite vasculitis treatment in Mediterranean patients.

Tripartite motif family proteins in inflammatory bowel disease: Mechanisms and potential for interventions

Inflammatory bowel disease (IBD) is a chronic recurrent gastrointestinal inflammatory disease that poses a heavy burden to the global healthcare system. However, the current paucity of mechanistic understanding of IBD pathogenesis hampers the development of aetiology‐directed therapies. Novel therapeutic options based on IBD pathogenesis are urgently needed for attaining better long‐term prognosis for IBD patients. The tripartite motif (TRIM) family is a large protein family including more than 70 structurally conservative members, typically characterized by their RBCC structure, which primarily function as E3 ubiquitin ligases in post‐translational modification. They have emerged as regulators of a broad range of cellular mechanisms, including proliferation, differentiation, transcription and immune regulation. TRIM family proteins are involved in multiple diseases, such as viral infection, cancer and autoimmune disorders, including inflammatory bowel disease. This review provides a comprehensive perspective on TRIM proteins' involvement in the pathophysiology and progression of IBD, in particular, on intestinal mucosal barriers, gene susceptibility and opportunistic infections, thus providing novel therapeutic targets for this complicated disease. However, the exact mechanisms of TRIM proteins in IBD pathogenesis and IBD‐related carcinogenesis are still unknown, and more studies are warranted to explore potential therapeutic targets of TRIM proteins in IBD.

Evaluation of the Clinical Effects and Frequency of MEFV Gene Mutation in Patients with Inflammatory Bowel Disease

Background

The clinical and pathological features of inflammatory bowel disease (IBD) and Familial Mediterranean Fever (FMF) are similar.

Objective

Here, the frequency of Mediterranean Fever (MEFV) gene mutation and its effect on the outcome of IBD were evaluated.

Methods

DNA sequence analysis detected the variants on the MEFV gene in patients with IBD. The relationship between mutations and the need for steroids, immunomodulators, biologics, and surgery was assessed.

Results

We evaluated 100 patients with IBD (55 with ulcerative colitis (UC) and 45 with Crohn's disease (CD)) and 60 healthy individuals as controls. The frequency of MEFV gene mutation was 26.7% (n = 12) and 14.5% (n = 8) for UC and CD, respectively. No relationship was found between MEFV gene mutation and the need for steroids, immunomodulators, and biologics (p = 0.446; p = 0.708; p > 0.999, resp.); however, in UC, the need for surgery in those with mutation (p = 0.018) and E148Q mutation alone was significant (p = 0.037).

Conclusion

The rate of MEFV gene mutations was high in patients with UC who required surgery. These patients have frequent and severe attacks, indicating that the mutations are related to disease severity. MEFV mutation as a modifier factor of IBD should be considered.

Metabolic Host-Microbiota Interactions in Autophagy and the Pathogenesis of Inflammatory Bowel Disease (IBD)

Inflammatory bowel disease (IBD) is a family of conditions characterized by chronic, relapsing inflammation of the gastrointestinal tract. IBD afflicts over 3 million adults in the United States and shows increasing prevalence in the Westernized world. Current IBD treatments center on modulation of the damaging inflammatory response and carry risks such as immunosuppression, while the development of more effective treatments is hampered by our poor understanding of the molecular mechanisms of IBD pathogenesis. Previous genome-wide association studies (GWAS) have demonstrated that gene variants linked to the cellular response to microorganisms are most strongly associated with an increased risk of IBD. These studies are supported by mechanistic work demonstrating that IBD-associated polymorphisms compromise the intestine's anti-microbial defense. In this review, we summarize the current knowledge regarding IBD as a disease of defects in host-microbe interactions and discuss potential avenues for targeting this mechanism for future therapeutic development.

Genetics and the axial spondyloarthritis spectrum

The axial SpAs (axSpAs) are clearly clinically a heterogeneous set of diseases with markedly varying extra-articular features. These diseases are all highly heritable and have overlapping but differing genetic origins. Shared features include association with HLA class I alleles and genes of the IL-23 pathway, among other things. Significant differences do exist however, both in the genetic loci involved and at specific loci in the individual genetic variants associated with each disease. These similarities and differences are of great interest in regards to disease pathogenesis and treatment development, although individually they are too small in effect to be of prognostic or diagnostic value. Polygenic risk scores, which capture a high proportion of the genetic variation between disorders, have been shown to have clinically useful discriminatory capacity in axSpA. This suggests they have the potential to enable improved disease classification, incorporating basic pathogenic features such as genomics, and ultimately benefitting clinical care. The aim of this article is to review the genetic characteristics of the spectrum of axSpAs and to discuss how this influences our understanding of the disease pathogenesis and the clinical implications of this understanding.

Familial Mediterranean fever: What associations to screen for?

Familial Mediterranean fever (FMF) is the most common and best known of hereditary recurrent fever or periodic fever syndromes. It was described in 1945 and genetically characterized in 1992. It is caused by a point mutation in the MEFV gene located on the short arm of chromosome 16. It is particularly frequent among Sephardic Jews, Armenians, Turks and Middle Eastern Arabs, where the prevalence can reach 1/2000 to 1/1000.

Recent publications described its frequent association with other diseases and/or syndromes, particularly those of autoimmune, genetic, and autoinflammatory origin.

The objective of this review is to familiarize healthcare professionals with the main associations to look for in patients followed for FMF. The early detection of these associations makes it possible to improve the management and the prognosis of patients with FMF.

FMF Is Associated With a Wide Spectrum of MHC Class I- and Allied SpA Disorders but Not With Classical MHC Class II-Associated Autoimmune Disease: Insights From a Large Cohort Study

Objectives: To test the hypothesis that familial Mediterranean fever (FMF)-associated autoinflammation may exaggerate the tendency toward adaptive immunopathology or spondyloarthritis (SpA)-associated disorders including major histocompatibility complex (MHC) class I associated disorders but not classical MHC class II-associated disorders that exhibit transplacental autoimmunity including myasthenia gravis and pemphigus.

Methods: Seven thousand seven hundred forty-seven FMF patients and 10,080 age- and sex-matched controls in the Clalit Health Services medical database were identified and compared in terms of prevalence of SpA-associated disorders. We also evaluated four classical and strong MHC class II-associated disorders, namely, pemphigus vulgaris, myasthenia gravis, sarcoidosis, and pernicious anemia, to ascertain whether such associations with SpA-spectrum disease were specific or merely reflected the non-specific consequences of innate immune system activation on driving divergent types of immunity. The diagnosis of FMF was based on the medical records and not genetically proven.

Results: FMF showed a strong association with MHC class I-related diseases: odds ratio (OR) of 28.58 [95% confidence interval (95% CI), 6.93–117.87; p < 0.0001] for Behçet's disease, OR of 10.33 (95% CI, 4.09–26.09; p < 0.0001) for ankylosing spondylitis, and OR of 1.67 (95% CI, 1.19–2.33; p = 0.0029) for psoriasis. For weakly MHC class I-linked diseases, an OR of 3.76 (95% CI, 2.48–5.69; p < 0.0001) for Crohn's disease and OR of 2.64 (95% CI, 1.52–4.56; p = 0.0005) for ulcerative colitis were found. No association was found between FMF and the four MHC class II-associated autoimmune disorders.

Conclusion: FMF patients are associated with increased risk of SpA-related disease diagnosis including MHC-I-opathies but not MHC-II-associated autoimmune diseases, suggesting that tissue-specific dysregulation of innate immunity share between FMF and SpA spectrum disorders may drive adaptive immune MHC class I-associated conditions.

Periodic fever syndromes: beyond the single gene paradigm

Familial Mediterranean fever (FMF) is the most common monogenic autoinflammatory disease in Canada and is characterized by a clinical syndrome of episodic inflammatory symptoms. Traditionally, the disease is defined by autosomal recessive inheritance of MEFV gene variants, yet FMF also not uncommonly manifests in individuals with only one identified disease-associated allele. Increasing availability and affordability of gene sequencing has led to the identification of multiple MEFV variants; however, they are often of unknown clinical significance. Variants in other genes affecting overlapping or distinct inflammatory signaling pathways - together with gene-environment interactions including epigenetic modulation - likely underlie the significant genetic and phenotypic heterogeneity seen among patients with this disease. We review recent evidence of the expanding spectrum of FMF genotype and phenotype and suggest that current drug funding schemes restricting biologic agents to patients with homozygous mutations have not kept pace with our biological understanding of the disease.

Genome-wide association study in Turkish and Iranian populations identify rare familial Mediterranean fever gene (MEFV) polymorphisms associated with ankylosing spondylitis

Ankylosing spondylitis (AS) is a highly heritable immune-mediated arthritis common in Turkish and Iranian populations. Familial Mediterranean Fever (FMF) is an autosomal recessive autoinflammatory disease most common in people of Mediterranean origin. MEFV, an FMF-associated gene, is also a candidate gene for AS. We aimed to identify AS susceptibility loci and also examine the association between MEFV and AS in Turkish and Iranian cohorts. We performed genome-wide association studies in 1001 Turkish AS patients and 1011 Turkish controls, and 479 Iranian AS patients and 830 Iranian controls. Serum IL-1β, IL-17 and IL-23 cytokine levels were quantified in Turkish samples. An association of major effect was observed with a novel rare coding variant in MEFV in the Turkish cohort (rs61752717, M694V, OR = 5.3, P = 7.63×10⁻¹²), Iranian cohort (OR = 2.9, P = 0.042), and combined dataset (OR = 5.1, P = 1.65×10⁻¹³). 99.6% of Turkish AS cases, and 96% of those carrying MEFV rs61752717 variants, did not have FMF. In Turkish subjects, the association of rs61752717 was particularly strong in HLA-B27-negative cases (OR = 7.8, P = 8.93×10⁻¹⁵), but also positive in HLA-B27-positive cases (OR = 4.3, P = 7.69×10⁻⁸). Serum IL-1β, IL-17 and IL-23 levels were higher in AS cases than controls. Among AS cases, serum IL-1β and IL-23 levels were increased in MEFV 694V carriers compared with non-carriers. Our data suggest that FMF and AS have overlapping aetiopathogenic mechanisms. Functionally important MEFV mutations, such as M694V, lead to dysregulated inflammasome function and excessive IL-1β function. As IL-1 inhibition is effective in FMF, AS cases carrying FMF-associated MEFV variants may benefit from such therapy.

Ankylosing spondylitis (AS) is a highly heritable immune-mediated arthritis. To identify new genetic associations with AS, we performed genome-wide association studies in Turkish and Iranian AS patients and controls. We identified a novel rare coding MEFV variant associated with AS. Rare polymorphisms of MEFV, which encodes the protein pyrin, are known to cause Familial Mediterranean Fever (FMF), a monogenic, autosomal recessive, autoinflammatory disease which can be complicated by arthritis. 99.6% of Turkish AS cases, and 96% of those carrying the MEFV variant, did not have FMF, and the association with AS remains excluding cases with FMF. In Turkish subjects, the MEFV variant association was particularly strong in HLA-B27-negative cases, but also positive in HLA-B27-positive cases. This represents the first rare variant association with AS, and has the highest odds ratio for AS of any non-MHC reported hitherto, indicating a major effect on disease pathogenesis. We assessed serum cytokine levels in the cohort, and found that IL-1β, IL-17 and IL-23 levels were higher in AS cases. Furthermore, among AS cases, IL-1β and IL-23 levels were increased in MEFV variant carriers compared with non-carriers. This study has therapeutic implications; as IL-1 inhibition is effective in FMF, AS cases carrying FMF-associated MEFV variants may benefit from such therapy.

Targeted Gene Sequencing in Children with Crohn's Disease and Their Parents: Implications for Missing Heritability

Crohn’s disease is a complex genetic trait characterized by chronic relapsing intestinal inflammation. Genome wide association studies (GWAS) have identified more than 170 loci associated with the disease, accounting for ∼14% of the disease variance. We hypothesized that rare genetic variation in GWAS positional candidates also contribute to disease pathogenesis. We performed targeted, massively-parallel sequencing of 101 genes in 205 children with Crohn’s disease, including 179 parent-child trios and 200 controls, both of European ancestry. We used the gene burden test implemented in VAAST and estimated effect sizes using logistic regression and meta-analyses. We identified three genes with nominally significant p-values: NOD2, RTKN2, and MGAT3. Only NOD2 was significant after correcting for multiple comparisons. We identified eight novel rare variants in NOD2 that are likely disease-associated. Incorporation of rare variation and compound heterozygosity nominally increased the proportion of variance explained from 0.074 to 0.089. We estimated the population attributable risk and total heritability of variation in NOD2 to be 32.9% and 3.4%, respectively, with 3.7% and 0.25% accounted for by rare putatively functional variants. Sequencing probands (as opposed to genotyping) to identify rare variants and incorporating phase by sequencing parents can recover a portion of the missing heritability of Crohn’s disease.

[Familial Mediterranean fever]

Familial Mediterranean Fever (FMF) is the most frequent monogenic auto-inflammatory disease. FMF is an autosomal recessive disease, which affects populations from Mediterranean origin and is associated with MEFV gene mutations encoding for the protein pyrin. Pyrin activation enhances the secretion of interleukin 1 by myelo-monocytic cells. Main features of the disease are acute attacks of serositis mainly located on the abdomen, less frequently on chest and joints, accompanied by fever and biological inflammatory markers elevation. Usually attacks last 1 to 3 days and spontaneously stop. A daily oral colchicine intake of 1 to 2mg/day is able to prevent attack's occurrence, frequency, intensity and duration among most patients. Colchicine is also able to prevent the development of inflammatory amyloidosis, the most severe complication of FMF. This state of the art article will focus on the diagnosis of FMF, the treatment and an update on the pathophysiology including the recent described dominant form of MEFV-associated new auto-inflammatory diseases.

Pyrin Inflammasome Regulates Tight Junction Integrity to Restrict Colitis and Tumorigenesis

BACKGROUND & AIMS

Inflammatory bowel diseases (IBD) increase risk for colorectal cancer. Mutations in the Mediterranean fever gene (MEFV or pyrin) are associated with hereditary autoinflammatory disease and severe IBD. Expression of MEFV, a sensor protein that the initiates assembly of the inflammasome complex, is increased in colon biopsies from patients with IBD. We investigated the role of pyrin in intestinal homeostasis in mice.

METHODS

Mefv-/- mice and C57/BL6 mice (controls) were given azoxymethane followed by multiple rounds of dextran sodium sulfate (DSS) to induce colitis and tumorigenesis. In some experiments, Mefv-/- mice were given injections of recombinant interleukin 18 (rIL18) or saline (control) during DSS administration. Colon tissues were collected at different time points during colitis development and analyzed by histology, immunohistochemistry, immunoblots, or ELISAs (to measure cytokines). Spleen and mesenteric lymph node were collected, processed, and analyzed by flow cytometry. Colon epithelial permeability was measured in mice with colitis by gavage of fluorescent dextran and quantification of serum levels.

RESULTS

MEFV was expressed in colons of control mice and expression increased during chronic and acute inflammation; high levels were detected in colon tumor and adjacent non-tumor tissues. Mefv-/- mice developed more severe colitis than control mice, with a greater extent of epithelial hyperplasia and a larger tumor burden. Levels of inflammatory cytokines (IL6) and chemokines were significantly higher in colons of Mefv-/- mice than control mice following colitis induction, whereas the level IL18, which depends on the inflammasome for maturation and release, was significantly lower in colons of Mefv-/- mice. Mefv-/- mice had increased epithelial permeability following administration of DSS than control mice, and loss of the tight junction proteins occludin and claudin-2 from intercellular junctions. STAT3 was activated (phosphorylated) in inflamed colon tissues from Mefv-/-, which also had increased expression of stem cell markers (OLFM4, BMI1, and MSI1) compared with colons from control mice. Administration of rIL18 to Mefv-/- mice reduced epithelial permeability, intestinal inflammation, the severity of colitis, and colon tumorigenesis.

CONCLUSIONS

In studies with DSS-induced colitis, we found that pyrin (MEFV) is required for inflammasome activation and IL18 maturation, which promote intestinal barrier integrity and prevent colon inflammation and tumorigenesis. Strategies to increase activity of MEFV or IL18 might be developed for the treatment of IBD and prevention of colitis-associated tumorigenesis.

Inflammasome biology, molecular pathology and therapeutic implications

Inflammasomes are intracellular multiprotein signaling complexes, mainly present in myeloid cells. They commonly assemble around a cytoplasmic receptor of the nucleotide-binding leucine-rich repeat containing receptor (NLR) family, although other cytoplasmic receptors like pyrin have been shown to form inflammasomes. The nucleation of the multiprotein scaffolding platform occurs upon detection of a microbial, a danger or a homeostasis pattern by the receptor that will, most commonly, associate with the adaptor protein ASC (apoptosis-associated speck-like protein containing a CARD) through homotypic domain interactions resulting in recruitment of procaspase-1. This will lead to the autoproteolytic activation of caspase-1, which regulates the secretion of proinflammatory IL1β and IL18 cytokines and pyroptosis, a caspase-1-mediated form of cell death. Pyroptosis occurs through cleavage of Gasdermin D, a membrane pore forming protein. Recently, non-canonical inflammasomes have been described, which directly sense intracellular pathogens through caspase-4 and -5 in humans, leading to pyroptosis. Inflammasomes are important in host defense; however, a deregulated activity is associated with a number of inflammatory, immune and metabolic disorders. Furthermore, mutations in inflammasome receptor coding genes are causal for an increasing number of rare autoinflammatory diseases. Biotherapies targeting the products of inflammasome activation as well as molecules that directly or indirectly inhibit inflammasome nucleation and activation are promising therapeutic areas. This review discusses recent advances in inflammasome biology, the molecular pathology of several inflammasomes, and current therapeutic approaches in autoinflammatory diseases and in selected common multifactorial inflammasome-mediated disorders.

Genetic association and phenotypic correlation of TLR4 but not NOD2 variants with Tunisian inflammatory bowel disease

OBJECTIVE

The common association between NOD2/CARD15 and TLR4 gene variants with inflammatory bowel disease (IBD) has not been replicated in all studies. We studied the polymorphism of these two genes in Tunisian patients with IBD.

METHODS

Polymorphisms of NOD2 (R702W, G908R and L1007fs) and TLR4 (Asp299Gly and Thr399Ile) genes were analyzed in 106 patients with IBD (68 with ulcerative colitis [UC], 38 with Crohn's disease [CD]) and 160 healthy controls using polymerase chain reaction-restriction fragment length polymorphism. Genotypes and phenotypes were correlated.

RESULTS

The mutated allele of TLR4-Thr399Ile was strongly associated with IBD (9.4% in IBD, 7.4% in UC and 13.2% in CD vs 2.5% in controls; P = 0.0004, 0.014 and 0.00006, respectively). Heterozygous genotypes were significantly more frequent in patients with IBD (17.0%), UC (14.7%) and CD (21.1%) than in controls (5.0%) (P = 0.0012, 0.012 and 0.001, respectively). Interestingly, the wild genotype was found to be protective (odds ratio 0.24). The mutated allele of TLR4-Asp299Gly was more frequent in controls (6.8%) than in patients with IBD (2.9%). A phenotypic correlation of Asp299Gly-AG genotype with arthritis in UC patients was detected (P = 0.003). Regarding the NOD2 gene, the common variations studied were not polymorphic and there was no genetic association with IBD.

CONCLUSION

The TLR4-Thr399Ile variant was strongly associated with susceptibility to IBD, whereas TLR4-Asp299Gly seems to play a role in the clinical expression of UC. The rarity and non-association of NOD2 mutations with IBD may reveal a genetic characteristic of the population in our region.

MEFV M694V mutation has a role in susceptibility to ankylosing spondylitis: A meta-analysis

OBJECTIVE

The aim of the current study was to determine the contributions of several common mutations in the Mediterranean fever (MEFV) gene, namely, E148Q, M680I, M694V and V726A, to ankylosing spondylitis (AS) susceptibility.

METHODS

Two investigators independently searched the literature regarding the association of MEFV with AS in the PubMed, EMBASE, Web of Science, and Scopus databases. They independently selected eligible articles and then extracted data from the included studies. The associations between MEFV mutations and AS risk were assessed with odds ratios (ORs) and 95% confidence intervals (95% CI). Further analyses were conducted with STATA 12.0 software (Stata Corp.; College Station, Texas, USA).

RESULTS

Four mutations (E148Q, M680I, M694V and V726A) were genotyped in 869 AS cases and 879 controls from the 8 eligible studies. Of the four mutations, M694V (pooled OR: 3.330, 95% CI: 2.129-5.208) was found to be associated with AS through overall analysis. However, the other mutations demonstrated no relation with AS (pooled ORs: 1.295, 1.258, 1.778; 95% CI: 0.886-1.891, 0.688-2.298 and 0.938-3.371). No significant publication bias was discovered in the meta-analysis.

CONCLUSIONS

The present study indicates that the MEFV M694V mutation may contribute to the pathogenesis of AS. The associations between the other mutations and AS need to be validated with more relevant and well-designed studies.

No shortcuts: new findings reinforce why nuance is the rule in genetic autoinflammatory syndromes

PURPOSE OF REVIEW

Practitioners dazed by the evolving concept of autoinflammation are in good company. Despite the clinical challenges autoinflammatory patients present, their study has been fundamental to our understanding of basic human inflammation. This review will focus on the ways in which recent discoveries in genetically mediated autoinflammation broaden and refine the concept.

RECENT FINDINGS

Major developments in pyrin inflammasome biology, defective ubiquitination, and the hyperferritinemic syndromes will be highlighted.

SUMMARY

We offer a brief discussion of discordance, convergence, genotype, and phenotype in autoinflammation. Additionally, we introduce the concepts of mutation dose effect and hybrid nomenclature. Overall, we hope to provide an update on developments in the field of autoinflammation, some conceptual tools to help navigate the rising tide of discovery, and some encouragement that keeping up with developments in autoinflammation is both exciting and necessary.

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.

Genomic architecture of inflammatory bowel disease in five families with multiple affected individuals

Currently, the best clinical predictor for inflammatory bowel disease (IBD) is family history. Over 163 sequence variants have been associated with IBD in genome-wide association studies, but they have weak effects and explain only a fraction of the observed heritability. It is expected that additional variants contribute to the genomic architecture of IBD, possibly including rare variants with effect sizes larger than the identified common variants. Here we applied a family study design and sequenced 38 individuals from five families, under the hypothesis that families with multiple IBD-affected individuals harbor one or more risk variants that (i) are shared among affected family members, (ii) are rare and (iii) have substantial effect on disease development. Our analysis revealed not only novel candidate risk variants but also high polygenic risk scores for common known risk variants in four out of the five families. Functional analysis of our top novel variant in the remaining family, a rare missense mutation in the ubiquitin ligase TRIM11, suggests that it leads to increased nuclear factor of kappa light chain enhancer in B-cells (NF-κB) signaling. We conclude that an accumulation of common weak-effect variants accounts for the high incidence of IBD in most, but not all families we analyzed and that a family study design can identify novel rare variants conferring risk for IBD with potentially large effect size, such as the TRIM11 p.H414Y mutation.

Inflammatory bowel disease in Turkish children

BACKGROUND

This study was undertaken to evaluate demographics, clinical manifestations, laboratory findings and outcomes of children with inflammatory bowel disease (IBD) in Turkey.

METHODS

We analyzed the medical records of 127 children diagnosed with IBD (under 18 years old) between January 2004 and January 2012 in 8 pediatric gastroenterology centers.

RESULTS

Of the 127 patients, 90 (70.9%) suffered from ulcerative colitis (UC), 29 (22.8%) from Crohn's disease (CD), and 8 (6.3%) from IBD unclassified. The mean age of the 127 patients was 11.6 ± 4.1 years, and 11.8% of the patients were below 5 years old. Of the patients, 49.6% were male, and males were more predominant in patients with CD than in those with UC (72.4% vs. 42.2%, P = 0.008; a male/female ratio of 2.62 in CD, P = 0.0016). Approximately one fifth of the patients had extra-intestinal manifestations and 13.3% of the patients had associated diseases. Extraintestinal manifestations and associated diseases were more common in early onset disease [P = 0.017, odds ratio (OR) = 4.02; P = 0.03, OR = 4.1]. Of the patients, 15% had normal laboratory parameters including anemia, high platelet count, hypoalbuminemia, hypoferritinemia, and high sedimentation rate. Area under receiver operation characteristics was used to predict pancolitis in patients with UC. The values of C-reactive protein, sedimentation rate and pediatric ulcerative colitis activity were 0.61 (P = 0.06), 0.66 (P = 0.01) and 0.76 (P = 0.0001), respectively. Four (4.4%) patients with UC underwent colectomy, and finally two (1.5%, 95% confidence interval: 0-3.7%) patients died from primary disease or complications.

CONCLUSIONS

IBD is an increasing clinical entity in Turkey. Features of IBD are similar to those in other populations, but prospective multicenter studies are needed to analyze the true incidence of IBD in Turkish children.

The immunogenetics of Behçet's disease: A comprehensive review

Behçet's disease is a chronic multisystem inflammatory disorder characterized mainly by recurrent oral ulcers, ocular involvement, genital ulcers, and skin lesions, presenting with remissions and exacerbations. It is thought that both environmental and genetic factors contribute to its onset and development. Although the etiology of Behçet's disease remains unclear, recent immunogenetic findings are providing clues to its pathogenesis. In addition to the positive association of HLA-B*51, which was identified more than four decades ago, and which has since been confirmed in multiple populations, recent studies report additional independent associations in the major histocompatibility complex class I region. HLA-B*15, -B*27, -B*57, and -A*26 are independent risk factors for Behçet's disease, while HLA-B*49 and -A*03 are independent class I alleles that are protective for Behçet's disease. Genome-wide association studies have identified associations with genome-wide significance (P < 5 × 10(-8)) in the IL23R-IL12RB2, IL10, STAT4, CCR1-CCR3, KLRC4, ERAP1, TNFAIP3, and FUT2 loci. In addition, targeted next-generation sequencing has revealed the involvement of rare nonsynonymous variants of IL23R, TLR4, NOD2, and MEFV in Behçet's disease pathogenesis. Significant differences in gene function or mRNA expression associated with the risk alleles of the disease susceptibility loci suggest which genes in a disease-associated locus influence disease pathogenesis. These genes encompass both innate and adaptive immunity and confirm the importance of the predominant polarization towards helper T cell (Th) 1 versus Th2 cells, and the involvement of Th17 cells. In addition, epistasis observed between HLA-B*51 and the risk coding haplotype of the endoplasmic reticulum-associated protease, ERAP1, provides a clue that an HLA class I-peptide presentation-based mechanism contributes to this complex disease.

Overcoming difficulty in diagnosis and differential diagnosis of Crohn's disease: the potential role of serological and genetic tests

Crohn's disease (CD) represents a heterogeneous group of chronic inflammatory disorders with various phenotypes. Establishing a definite diagnosis of CD should be based upon a combined assessment of clinical, endoscopic, radiological and pathological features. Although segmental disease distribution, transmural inflammation and non-caseating epithelioid granulomas have been considered as a 'hallmarks' for CD, clear diagnosis of CD in some patients has been challenging, due to overlapping endoscopic, radiographic and histologic features with other inflammatory bowel disease-like conditions. Laboratory markers (serological and genetic tests) may provide additional clues for the diagnosis and differential diagnosis of CD. This review focuses on the application of the currently available serological and genomic markers and in diagnosis and differential diagnosis of CD.

Association between MEFV Mutations M694V and M680I and Behçet's Disease: A Meta-Analysis

Objective

Several studies have identified an association between Behçet’s disease (BD) and mutations in the Mediterranean fever (MEFV) gene, which was originally linked to the autosomal recessive disease, Familial Mediterranean fever. However, no consensus has been reached. Here, a meta-analysis was conducted on published data to comprehensively evaluate this relationship.

Methods

Literature searches were performed in Pubmed, Embase, the Web of Science, and HuGE Navigator databases, in order to identify studies pertaining to the association between MEFV mutations and BD. Two investigators independently extracted and evaluated the data from eligible studies. The association between MEFV mutations (M694V, M680I, and E148Q) and BD was estimated overall by the odds ratio (OR) and 95% confidence intervals (95% CI). Further analysis was conducted with STATA 12.0 software (Stata Corp.; College Station, TX).

Results

Eligible studies (n=8) included genotyping data obtained from 2538 BD patients and 2792 healthy controls. Of the three mutations, M694V (pooled OR: 2.60, 95% CI: 2.02-3.34) and M680I (pooled OR: 1.74, 95% CI: 1.23-2.46) were found to be associated with BD in the overall analysis. The third mutation, E148Q, however, was not found to be linked with BD (pooled OR: 1.26, 95% CI: 0.69-2.31). Subgroup analysis furthermore revealed that M694V and M680I were risk loci for BD specifically in Turkish patients.

Conclusions

The meta-analysis confirmed that MEFV mutations M694V and M680I were associated with BD. Additional studies from other ethnic populations and functional experiments are necessary to determine the extent to which the MEFV gene underlies the development of BD.

Treatment of Crohn’s disease and familial Mediterranean fever by leukopheresis: Single shot for two targets

Coexistence of Crohn's disease (CD) and familial Mediterranean fever (FMF) is a rare condition and knowledge about this clinical situation is limited with a few case reports in the literature. The treatment of both diseases depends on their individual therapies. However, it is very hard to deal with this coexistence when CD is refractory to standard therapies. Ongoing activity of CD triggers the clinical attacks of FMF and the symptoms like abdominal pain interfere with both disease presentations which can cause problems about diagnostic and therapeutic approach. The main therapeutic agent for FMF is colchicine and diarrhea is the most common side effect of this drug. This side effect also causes problems about management of these diseases when both of them are clinically active. Here we report probably the first case in the literature with coexisting CD and FMF who was successfully treated by leukopheresis since he was refractory to conventional therapies for CD.

Small bowel mucosal damage in familial Mediterranean fever: results of capsule endoscopy screening

OBJECTIVE

Familial Mediterranean fever (FMF) is the most common form of autoinflammatory diseases. We aimed to evaluate the small bowel mucosa by capsule endoscopy (CE) in FMF patients for investigation of other possible causes of abdominal pain.

MATERIAL AND METHODS

The study group consisted of 41 patients with FMF. A standard questionnaire was used to record the gastrointestinal symptoms, other clinical findings, Mediterranean fever gene (MEFV) mutations, and history of medications including non-steroidal anti-inflammatory drugs (NSAIDs). Gastroscopy, colonoscopy and small bowel CE were performed in all patients, and biopsies were taken from terminal ileum and duodenum.

RESULTS

The mean age of the patients was 34 ± 11 years, 63% of them were female, and 76.5% of them were carrying MEFV exon 10 mutations. Only one patient used NSAIDs in addition to colchicine. In endoscopic investigations, gastric erosion was detected in only one patient, and no significant findings were detected in colonoscopy. CE showed small bowel mucosal defects in 44% (erosions in 26.8%, ulcer in 17.1%) and edema in 29.3% of the patients. Most (64%) of the ulcer and erosions were localized to jejunum, and only 24% were in ileum. Mitotic changes as an indirect finding of colchicine toxicity were not different from the changes observed in samples of independent group of patients with irritable bowel syndrome.

CONCLUSION

Mucosal defect was observed in half of the FMF patients, which may be associated with underlying inflammation or chronic colchicine exposure. Detection of nonspecific chronic inflammation without mitotic changes supports that mucosal defects may be associated with the autoinflammatory process.

Detection of Mediterranean fever gene mutations in Egyptian children with inflammatory bowel disease

AIM

The aim of the current study is to investigate the prevalence of familial Mediterranean fever gene (MEFV) mutations in a cohort of Egyptian children with inflammatory bowel disease (IBD), and to characterize familial Mediterranean fever (FMF)-IBD patients, helping better understanding of IBD pathogenesis.

METHODS

The study enrolled 17 patients with ulcerative colitis (UC), 15 with Crohn's disease(CD), 10 with indeterminate colitis (IC) and 33 healthy children as controls. All cases and controls were tested for 12 FMF gene mutations by reverse hybridization after multiplex polymerase chain reaction amplification and DNA sampling.

RESULTS

Eighty-eight percent of the IBD patients carried the mutations, with Sequence variant V627A being the commonest versus 42.4% of controls. No associations were found between MEFV gene mutations, and phenotypic characteristics of IBD patients.

CONCLUSION

IBD patients, in populations with a high background carrier rate of MEFV variants, should be screened for MEFV gene mutations, especially those diagnosed as indeterminate colitis. Testing larger numbers of healthy Egyptian children for MEFV gene mutation is important to further determine the allele frequency in Egypt.

Association of familial Mediterranean fever in Turkish children with inflammatory bowel disease

AIM

Familial Mediterranean fever (FMF) and inflammatory bowel disease (IBD) carry similar clinical and biological properties. Both are characterized with chronic inflammation attacks and neutrophil migration and impaired apoptosis mechanism are present in the areas of damage in both conditions. In our study, we aimed to determine the frequency of association of FMF in patients with IBD, to compare the demographic, clinical, laboratory and treatment response properties in these patients with the ones in other IBD patients and to determine association of FMF especially in treatment-resistant patients.

MATERIAL AND METHODS

Fifty-three patients who were being followed up with a diagnosis of IBD aged between 0 and 18 years were included in the study. The patient group included the patients who were diagnosed with IBD according to clinical, serological, endoscopic and histopathological criteria, who were being followed up and whose therapies were continuing. Genetic analysis in terms of MEFV gene mutations was performed in all patients with a diagnosis of IBD. Acute phase reactants, complete blood count, immunoglobulin levels, stool analysis, "perinuclear anti-neutrophil cytoplasmic antibodies" (pANCA) and "anti-Saccharomyces cerevisiae antibodies" (ASCA) were studied at the time of diagnosis. The diagnosis of FMF was made according to detailed history, physical examination findings, laboratory tests and the results of genetic analyses in terms of MEFV gene mutations in accordance with the criteria defined in 2009.

RESULTS

We found that FMF accompanied in 14 (26.4%) of the patients who had a diagnosis of IBD. 3 of these 14 patients in whom FMF accompanied were being followed up with a diagnosis of Crohn disease and 11 were being followed up with a diagnosis of ulcerative colitis. All of these patients had MEFV gene mutation. These mutations included M694V (50%), K695R (21.4%), M680I (14.3%) and R202Q (14.3%) in order of frequency. When the laboratory data were compared between the patients who had a diagnosis of IBD alone and who had a diagnosis of IBD plus FMF, it was observed that the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) values were statistically significantly higher in the IBD+FMF group.

CONCLUSIONS

FMF is a common condition in the Turkish population and M694V mutation is found most commonly. In our study, this status did not change in cases where FMF accompanied IBD, but K695R mutation was found more frequently compared to FMF alone. We think that it should be kept in mind that other inflammatory conditions including mainly FMF may accompany IBD, if a case of IBD does not have an expected course or is resistant to treatment.

Mediterranean fever (MEFV) variant P369S/R408Q in a patient with entero-Behçet's disease who successfully responded to treatment with colchicine

A 57-year-old Japanese woman who had been diagnosed as having entero-Behçet's disease nine years earlier was admitted with a persistent high-grade fever. An Mediterranean fever (MEFV) gene analysis revealed the compound heterozygous P369S-R408Q variant. She was treated with colchicine, and her symptoms immediately improved. Prednisolone (PSL) was added to treat the punched-out ulcers in the terminal ileum, leading to remission. There has been no relapse since the PSL was discontinued. In Behçet's disease patients with MEFV variants, the use of colchicine should therefore be considered in such patients as well as immunosuppressive therapy.

Targeted resequencing implicates the familial Mediterranean fever gene MEFV and the toll-like receptor 4 gene TLR4 in Behçet disease

Genome-wide association studies (GWAS) are a powerful means of identifying genes with disease-associated common variants, but they are not well-suited to detecting genes with disease-associated rare and low-frequency variants. In the current study of Behçet disease (BD), nonsynonymous variants (NSVs) identified by deep exonic resequencing of 10 genes found by GWAS (IL10, IL23R, CCR1, STAT4, KLRK1, KLRC1, KLRC2, KLRC3, KLRC4, and ERAP1) and 11 genes selected for their role in innate immunity (IL1B, IL1R1, IL1RN, NLRP3, MEFV, TNFRSF1A, PSTPIP1, CASP1, PYCARD, NOD2, and TLR4) were evaluated for BD association. A differential distribution of the rare and low-frequency NSVs of a gene in 2,461 BD cases compared with 2,458 controls indicated their collective association with disease. By stringent criteria requiring at least a single burden test with study-wide significance and a corroborating test with at least nominal significance, rare and low-frequency NSVs in one GWAS-identified gene, IL23R (P = 6.9 × 10(-5)), and one gene involved in innate immunity, TLR4 (P = 8.0 × 10(-4)), were associated with BD. In addition, damaging or rare damaging NOD2 variants were nominally significant across all three burden tests applied (P = 0.0063-0.045). Furthermore, carriage of the familial Mediterranean fever gene (MEFV) mutation Met694Val, which is known to cause recessively inherited familial Mediterranean fever, conferred BD risk in the Turkish population (OR, 2.65; P = 1.8 × 10(-12)). The disease-associated NSVs in MEFV and TLR4 implicate innate immune and bacterial sensing mechanisms in BD pathogenesis.