Mapping of a gene causing familial Mediterranean fever to the short arm of chromosome 16

[Challenges in diagnosing familial Mediterranean fever: exploring atypical clinical features. Clinical case]

This clinical case series presents descriptions of 3 patients with familial Mediterranean fever (FMF) who have atypical manifestations and abnormal inheritance mechanisms in terms of Gregor Mendel's laws. Although molecular genetic testing can help with disease diagnosis, it is not always conclusive. The primary need for genetic testing in atypical cases is to explain the mechanism of inflammation and to select the optimal therapy. These clinical observations demonstrate the changes in the spectrum of phenotypic manifestations of FMF in the context of the widespread introduction of molecular genetic methods.

Autoinflammatory Contributors to Cytokine Storm

Cytokine Storm is a complex and heterogeneous state of life-threatening systemic inflammation and immunopathology. Autoinflammation is a mechanistic category of immune dysregulation wherein immunopathology originates due to poor regulation of innate immunity. The growing family of monogenic Systemic Autoinflammatory Diseases (SAIDs) has been a wellspring for pathogenic insights and proof-of-principle targeted therapeutic interventions. There is surprisingly little overlap between SAID and Cytokine Storm Syndromes, and there is a great deal to be inferred from those SAID that do, and do not, consistently lead to Cytokine Storm. This chapter will summarize how illustrations of the autoinflammatory paradigm have advanced the understanding of human inflammation, including the role of autoinflammation in familial HLH. Next, it will draw from monogenic SAID, both those with strong associations with cytokine storm and those without, to illustrate how the cytokine IL-18 links innate immune dysregulation and cytokine storm.

Investigation of the relationship between disease severity and development of amyloidosis and genetic mutation in FMF disease

BACKGROUND

Familial Mediterranean fever (FMF) is an autosomal recessive genetic disease. Amyloidosis is the most important complication of FMF that determines the prognosis of the disease.

AIMS

In our study, we have investigated the relationship between the genetic mutations with the disease severity and the frequency of development of amyloidosis inpatients with FMF.

METHODS

A total of 148 patients with FMF were included this study. The relationship between disease activity score, clinical findings, response to treatment, and presence of amyloid and genetic mutations were evaluated.

RESULTS

One hundred forty-eight patients (80 women (54%), 68 men (46%)) were enrolled over 18 years of age. The mean age of the patients was 30.98 ± 11.18 (18-67) years. In our study, the most frequently seen mutations are M694V, M680I, R202Q, and E148Q, respectively. The most common genotype is M694V/M694V mutation and this mutation has been found in 37 patients (25%). In 25 patients, M694V heterozygous have been found (16.8%). The third frequent mutationis M694V/M680I/R202Q has been found in13 patients (8.7%). In 23 patients, amyloidosis has been developed. Ten patients with amyloidosis have M694V homozygous mutations (27%) and 5 patients with amyloidosis M694V heterozygous (20%) mutations. The both of the two patients who carry the homozygous E148Q mutations have developed amyloidosis.

CONCLUSIONS

In our study, the distribution of the frequency of mutations is consistent with other similar studies performed in Turkey. We found that patients with M694V mutation had a significantly higher rate of exacerbation, higher drug doses for treatment, and a close relationship with amyloidosis, as compared to patients with other mutations.

MEFV gene allele frequency and genotype distribution in 3230 patients' analyses by next generation sequencing methods

Familial Mediterranean Fever (FMF, OMIM ID: 249100) is the most common autoinflammatory, autosomal recessive disease caused by mutations in the MEFV gene. It is widespread in the Mediterranean, primarily among Turkish, Armenian, Arab and Jewish. This study aims to examine genotype distributions of common MEFV variants in the Turkish population using targeted NGS and to evaluate all rare mutations. It included 3230 people applying to Ege University Children's Hospital Molecular Medicine Laboratory with the suspicion of autoinflammatory disease between 2017 and 2021. MEFV missense variant was detected in 1839 (56.9%) individuals. One or more mutations were found in them. 1063 patients were heterozygous (57.8%), 410 were compound heterozygous (22.3%), 238 were complex genotype (12.9%), and 128 were homozygous (7%). 56 different mutations and 141 genotypes were detected, two of which were novel (p.His87Arg, c.260A > G and p.Leu396Phe, c.1186C > T). These were determined as 6benign, 40 uncertain significant, 3 likely pathogenic and 7 pathogenic according to the ACMG classification. The most common ones were R202Q (n = 1097, 37.48%), E148Q (n = 512, 17.49%), M694V (n = 493, 16.84%), V726A (n = 155, 5.30%), M680I (n = 150, 5.12%), P369S (n = 108, 3.69%), R408Q (n = 95, 3.25%) respectively. They constitute 89.17 % of the entire patient population. In conclusion, DNA variants/mutations in the MEFV gene were evaluated in 3230 patients. To date, no mutation screening has been encountered in such a large population using NGS. Genotype distributions of both common and rare mutations were revealed. The obtained data will hopefully contribute to the future genotype-phenotype studies of FMF disease.

The Interactions Between Autoinflammation and Type 2 Immunity: From Mechanistic Studies to Epidemiologic Associations

Autoinflammatory diseases are a group of clinical syndromes characterized by constitutive overactivation of innate immune pathways. This results in increased production of or responses to monocyte- and neutrophil-derived cytokines such as interleukin-1β (IL-1β), Tumor Necrosis Factor-α (TNF-α), and Type 1 interferon (IFN). By contrast, clinical allergy is caused by dysregulated type 2 immunity, which is characterized by expansion of T helper 2 (Th2) cells and eosinophils, as well as overproduction of the associated cytokines IL-4, IL-5, IL-9, and IL-13. Traditionally, type 2 immune cells and autoinflammatory effectors were thought to counter-regulate each other. However, an expanding body of evidence suggests that, in some contexts, autoinflammatory pathways and cytokines may potentiate type 2 immune responses. Conversely, type 2 immune cells and cytokines can regulate autoinflammatory responses in complex and context-dependent manners. Here, we introduce the concepts of autoinflammation and type 2 immunity. We proceed to review the mechanisms by which autoinflammatory and type 2 immune responses can modulate each other. Finally, we discuss the epidemiology of type 2 immunity and clinical allergy in several monogenic and complex autoinflammatory diseases. In the future, these interactions between type 2 immunity and autoinflammation may help to expand the spectrum of autoinflammation and to guide the management of patients with various autoinflammatory and allergic diseases.

Evaluation of S100A12 protein levels in children with familial Mediterranean fever

Background/aim

Familial Mediterranean fever (FMF), the most common autoinflammatory disease in children, is characterized by recurrent febrile episodes. FMF is known to progress with chronic inflammation, particularly during attack periods. This study aimed to investigate the relationship of S100A12, an inflammatory marker, with attacks and inflammatory events in FMF patients.

Materials and methods

The study included 57 patients diagnosed with FMF, 43 in an attack-free period and 14 in an attack period, and 31 healthy children as the control group. Only white blood cell (WBC) count, C-reactive protein (CRP) level, erythrocyte sedimentation rate (ESR), and S100A12 level were analyzed in the control group. In addition, serum amyloid A (SAA), and fibrinogen levels were measured, and a mutation analysis was performed in the patient group. The results were compared among the attack-free period, acute attack FMF and control groups.

Results

The mean age of patients and control group was 10 (2.5–18) and 9.5 (2.5–16) years, respectively. The CRP (p = 0.001), S100A12 (p = 0.003) and ESR (p= 0.001) values differed significantly between the FMF and control groups. S100A12 level (p = 0.027), WBC count (p = 0.003), CRP level (p = 0.0001), ESR (p = 0.004), and fibrinogen level (p = 0.001) differed significantly between the acute attack and attack-free period groups. SAA level (p = 0.05), ESR (p = 0.001), fibrinogen level (p = 0.001), WBC count (p = 0.001), and S100A12 level (p = 0.027) were higher in M694V homozygous FMF patients than in other FMF patients.

Conclusion

Patients with FMF had higher S100A12 levels than the control group, while the mean S100A12 concentration was higher in acute attack period patients than in attack-free period patients. S100A12 level might be an important indicator in the monitoring of chronic inflammation in patients with FMF.

Coexisting Diseases in Patients with Familial Mediterranean Fever

Background and Aims

Familial Mediterranean fever (FMF) is a prototype of autoinflammatory disease and mainly associated with MEFV gene mutations. This single-center study as an experience represents FMF-coexisting disease in the FMF registration database.

Methods

Four hundred patients who had FMF based on clinical criteria (Tel-Hashomer) and/or MEFV mutations enrolled the study. Twelve most common MEFV mutations (P369S, F479L, M680I (G/C), M680I (G/A), I692del, M694V, M694I, K695R, V726A, A744S, R761H, E148Q) were analyzed if needed by the reverse hybridization assay. Any co-existed disease had been confirmed by a related subspecialist. All data were analyzed by a simple analytical method.

Results

Fifty-seven (14%) patients had associated disease, 32 patients were male and 24 patients were under 10 years old. They included 92 MEFV variant alleles and only in five patients there were not any mutations. The most common variant alleles were M694V (36%), E148Q (22%), V726A (17%), M680I (1%) and M694I (0.07%) respectively. Rheumatologic disorders were the most common coexisting disease, then followed by gastrointestinal and neurological disorders. Some rare diseases such as TTP, growth hormone deficiency, multiple sclerosis, idiopathic ascites, Leiden factor V deficiency and Felty syndrome have been detected. Homozygote mutations of (M694V-M694V) were associated with idiopathic ascites, orchitis and pericarditis.

Conclusion

Coexisting disease in patients with FMF is presented with positive MEFV gene mutations particularly with these five common variant alleles: M694V, E148Q, V726A, M680I, and M694I. The commonly associated diseases are rheumatologic, gastrointestinal and CNS disorders.

Mesothelioma in Familial Mediterranean Fever With Colchicine Intolerance: A Case Report and Literature Review

A 65-year-old Italian physician affected by Familial Mediterranean fever (FMF) was hospitalized due to progressive abdominal enlargement, which had begun 6 months before admission. Physical examination revealed ascites and bilateral leg edema. Abdominal CT scan showed ascitic fluid and extensive multiple peritoneal implants; peritoneal CT-guided biopsy revealed an epithelial-type malignant mesothelioma. The patient's past medical history revealed recurrent episodes of abdominal pain and fever from the age of 2. Clinical diagnosis of FMF was suspected at the age of 25, while genetic analysis, performed at the age of 50, confirmed homozygosity for the M694I mutation in the MEFV gene. Treatment with the first line FMF drug colchicine was started and stopped several times because of worsened leukopenia. The patient in fact had a history of asymptomatic leukopenia/lymphopenia from an early age; the intake of colchicine aggravated his pre-existing problem until the definitive suspension of the drug. As for second-line drugs, canakinumab was first prescribed, but due to prescription issues, it was not possible to be administered. When he was given anakinra, there was a worsening of leukopenia leading to septic fever. Systematic literature review indicates that, in most cases, recurrent peritoneal inflammation results in benign peritoneal fibrosis or less commonly in encapsulating peritonitis. There are only a few reported cases of recurrent peritoneal inflammation progressing from FMF to peritoneal mesothelioma (MST). In such cases, intolerance to colchicine or its erratic intake may lead to long-term recurrent inflammation, which usually precedes the development of the tumor, while pre-existing leukopenia, as in our patient, could also be a factor promoting or accelerating the tumor progression. In conclusion, we suggest that in the presence of intolerance or resistance to colchicine, interleukin (IL)-1 inhibition could suppress peritoneal inflammation and prevent MSTs.

Next-generation screening of a panel of genes associated with periodic fever syndromes in patients with Familial Mediterranean Fever and their clinical characteristics

Familial Mediterranean Fever (FMF) is a hereditary fever syndrome that primarily affects Mediterranean populations. For the study, total number of 182 patients with FMF disease were enrolled and screening of a panel of genes , called "fever panel" which comprises 17 genes, was performed. The most common mutations in MEFV gene were homozygous M694V missense mutation (4.3%) and R202Q missense mutation (4.9%). The most common heterozygous mutations were R202Q (26.5%), M694V (25.9%) and E148Q (11.9%). Compound heterozygous and homozygous mutations were also detected. Also, different types of mutations were identified in NOD2, CARD14, NLRP12, NLRP3, NLRP7, IL1RN, LPIN2, TNFRSF1A, MVK and PSTPIP1 genes. Two novel missense variations in the MEFV gene, Gln34Pro and Ile247Val, which have not been previously reported in the databases, were identified. Also, Thr91Ile missense variation in the NOD2 gene, Gly461Cys missense variation in NLRP3 and Tyr732Stop nonsense variation in LPIN2 were firstly identified. The results of the current study suggest that in addition to the MEFV gene which has an important roles in FMF, molecular screening of other genes related to other autoinflammatory diseases might provide support in suspected cases and provide detailed information about the course of the disease.

Familial Mediterranean fever and atherosclerosis in childhood and adolescence

Familial Mediterranean fever is a chronic inflammatory disease characterized by periodic and self-limited episodes of fever and aseptic polyserositis. Although colchicine treatment has altered the course of the disease, it is believed that subclinical inflammation is still present, leading to endothelial dysfunction and atherosclerosis in the course of time. In this review, following the published recommendations, we queried online databases such as MEDLINE Pubmed, Scopus, and Web of science for peer-reviewed studies and reviews written in English language, using the following keywords: familial Mediterranean fever, children, endothelial dysfunction, atherosclerosis, cardiovascular disease. The objective of this review is to highlight the correlation between familial Mediterranean fever and atherosclerosis, and moreover to describe new serum inflammatory markers and non-invasive methods of endothelial dysfunction, to detect the atherosclerosis process early starting from childhood.

Association between MEFV polymorphisms and the susceptibility to ankylosing spondylitis in a Chinese Han population: A case-control study

The aim of this study was to explore the genetic association of Mediterranean fever (MEFV) gene polymorphisms rs3743930 and rs11466023 with ankylosing spondylitis (AS) susceptibility in a cohort of Chinese Han population.Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used for genotyping MEFV polymorphisms in 131 AS patients and 127 healthy controls. Chi-square test was employed to compare the genotype and allele distributions between the case and control groups. Odds ratio (OR) with 95% confidence interval (CI) was calculated to assess the association between MEFV gene polymorphisms and AS incidence.The frequency of the G allele of MEFV polymorphism rs3743930 in the AS group was significantly higher than that in the healthy control group (36.64% vs 28.35%, P < .05). And individuals carrying the GG genotype showed 2.896 folds higher risk of developing AS when compared with CC genotype carriers (OR = 2.896, 95% CI = 1.115-7.519). But no significant differences were detected in either genotype or allele distributions between case and control groups for the polymorphism rs11466023 (P > .05).MEFV gene polymorphism rs3743930 might be significantly associated with AS susceptibility in Chinese Han population, and its G allele might predict high risk of AS.

New autoinflammatory diseases

PURPOSE OF REVIEW

Advances in sequencing techniques and systematic cohort-analysis of patients with autoinflammatory phenotypes have enabled a burst in the recognition of new autoinflammatory diseases and contributed to the description of the mechanisms involved in autoinflammation. This review focuses on new genetic and mechanistic discoveries that have broadened the definition of autoinflammatory diseases in the context of the established landscape, providing new therapeutic opportunities and avenues for further discoveries.

RECENT FINDINGS

Mechanistic insights of inflammatory diseases open opportunities for new targeted therapies. Advances in high-throughput screening of small-molecule inhibitors accelerate the discovery of new and more specific therapeutic options. Recent evidence establishes IL-18 as a driver of macrophage activation, emerging as a new biomarker and therapeutic target. Finally, the identification of escape of nonsense-mediated decay as the genetic mechanism resulting in a monogenic immune-dysregulatory disease, unveils a possibility for future discoveries.

SUMMARY

Recent mechanistic findings in autoinflammatory diseases as well as the identification of specific biomarkers and discovery of new diseases, continue to pave the way for ever more specific targeted approaches. These therapies are not only applicable to monogenic autoinflammatory syndromes but also for other diseases in which the same pathways are dysregulated.

Posttranslational Modification as a Critical Determinant of Cytoplasmic Innate Immune Recognition

Cell surface innate immune receptors can directly detect a variety of extracellular pathogens to which cytoplasmic innate immune sensors are rarely exposed. Instead, within the cytoplasm, the environment is rife with cellular machinery and signaling pathways that are indirectly perturbed by pathogenic microbes to activate intracellular sensors, such as pyrin, NLRP1, NLRP3, or NLRC4. Therefore, subtle changes in key intracellular processes such as phosphorylation, ubiquitination, and other pathways leading to posttranslational protein modification are key determinants of innate immune recognition in the cytoplasm. This concept is critical to establish the “guard hypothesis” whereby otherwise homeostatic pathways that keep innate immune sensors at bay are released in response to alterations in their posttranslational modification status. Originally identified in plants, evidence that a similar guardlike mechanism exists in humans has recently been identified, whereby a mutation that prevents phosphorylation of the innate immune sensor pyrin triggers a dominantly inherited autoinflammatory disease. It is also noteworthy that even when a cytoplasmic innate immune sensor has a direct ligand, such as bacterial peptidoglycan (NOD1 or NOD2), RNA (RIG-I or MDA5), or DNA (cGAS or IFI16), it can still be influenced by posttranslational modification to dramatically alter its response. Therefore, due to their existence in the cytoplasmic milieu, posttranslational modification is a key determinant of intracellular innate immune receptor functionality.

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

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

Screening of Free Carnitine and Acylcarnitine Status in Children With Familial Mediterranean Fever

OBJECTIVES

This study aims to demonstrate the patterns of free carnitine (FC) and acylcarnitine (AC) esters in familial Mediterranean fever (FMF) patients.

PATIENTS AND METHODS

A total of 205 patients (106 males, 99 females; mean age 131.3±52.1 months; range 24 to 254 months) with FMF and 50 healthy controls (27 males, 23 females; mean age 125.7±49.6 months; range 32 to 217 months) were enrolled. Fasting dried blood samples were taken for showing FC and AC ester levels with tandem mass spectrometry from both patients and controls.

RESULTS

Screening of AC profile revealed increased FC, 3-hydroxypalmitoylcarnitine (C16-OH), and 3-Hydroxy octadecanoylcarnitine (C18:2-OH) carnitine levels, while decreased acetyl-carnitine (C2), propionyl-carnitine (C3), butyryl-carnitine (C4), tiglyl-carnitine (C5:1), hexanoyl-carnitine (C6), octanoyl-carnitine (C8), decenoylcarnitine (C10:1), decadienoylcarnitine (C10:2), malonylcarnitine (C3DC), methylmalonylcarnitine (C4DC), glutarylcarnitine (C5DC), hexadecenoylcarnitine (C16:1), 3-Hydroxy butyrylcarnitine (C4-OH), and 3-Hydroxy oleylcarnitine (C18:1-OH) carnitine levels in FMF patients compared to controls. Total AC levels (p<0.001) and AC to FC ratio (p<0.001) were also lower in FMF patients than the controls.

CONCLUSION

In this study, we were able to detect some of the AC profile variations in FMF patients; however, usage of carnitine in all patients with FMF is not recommended since we were not able to demonstrate secondary carnitine deficiency in FMF patients of this study.

Unified Modeling of Familial Mediterranean Fever and Cryopyrin Associated Periodic Syndromes

Familial mediterranean fever (FMF) and Cryopyrin associated periodic syndromes (CAPS) are two prototypical hereditary autoinflammatory diseases, characterized by recurrent episodes of fever and inflammation as a result of mutations in MEFV and NLRP3 genes encoding Pyrin and Cryopyrin proteins, respectively. Pyrin and Cryopyrin play key roles in the multiprotein inflammasome complex assembly, which regulates activity of an enzyme, Caspase 1, and its target cytokine, IL-1β. Overproduction of IL-1β by Caspase 1 is the main cause of episodic fever and inflammatory findings in FMF and CAPS. We present a unifying dynamical model for FMF and CAPS in the form of coupled nonlinear ordinary differential equations. The model is composed of two subsystems, which capture the interactions and dynamics of the key molecular players and the insults on the immune system. One of the subsystems, which contains a coupled positive-negative feedback motif, captures the dynamics of inflammation formation and regulation. We perform a comprehensive bifurcation analysis of the model and show that it exhibits three modes, capturing the Healthy, FMF, and CAPS cases. The mutations in Pyrin and Cryopyrin are reflected in the values of three parameters in the model. We present extensive simulation results for the model that match clinical observations.

30 years hids-Travels between bedside and bench

In this paper I describe more than 30 years of investigations of the autoinflammatory syndrome hyper-IgD syndrome (HIDS). In the first paper after the recognition of the syndrome published in 1984, we described the characteristics of this periodic fever syndrome. The hypotheses regarding the pathogenesis of the fever and the acute phase response in these patients prompted us to study interleukin-1 (IL-1), the cytokine formerly described as endogenous pyrogen and lymphocyte activating factor. Although we were unable to find elevated concentrations of IL-1 in the circulation, we discovered that white blood cells spontaneously produced elevated amounts of IL-1b. A major next discovery was the identification of the gene defect by us and others in 1999: quite unexpectedly the mevalonate kinase, an enzyme in the cholesterol synthesis pathway was found to be mutated. We were able to describe a founder effect and a phenotypic continuum with the classical mevalonate aciduria in the years to follow. A major step forward was the finding that recombinant interleukin-1 receptor antagonist (anakinra) was an effective treatment for the majority of patients. Thus, research over a period of three decades after the first recognition of the syndrome, has yielded much insight into the pathogenesis as well as an effective therapy for HIDS.

Mutations in the B30.2 domain of pyrin and the risk of ankylosing spondylitis in the Chinese Han population: a case-control study

Ankylosing spondylitis (AS) and familial Mediterranean fever (FMF) are a common autoimmune disease and a classic autoinflammatory disease, respectively. Mediterranean fever (MEFV) encodes the pyrin protein and is the causal disease gene in FMF. This protein is an important regulator of innate immunity and may play a key role in the development of AS. To identify the mutations in the B30.2 domain of pyrin and to uncover the relationships between these mutations and AS risk in the Chinese Han population, we extracted genomic DNA from the peripheral blood of 200 AS patients and 200 matched controls and performed polymerase chain reactions (PCRs) and direct sequencing on those samples. Statistical analysis indicated that only Met694Val (rs61752717) in the B30.2 domain of pyrin could affect the risk of AS (P = 0.042; odds ratio [OR] = 5.103; 95% confidence interval [CI] = 1.111-23.437 for the model of Met (M) vs. Val (V), P = 0.040; OR = 5.211; 95% CI = 1.127-24.091 for the model of MM vs. MV+VV). Moreover, M694V is significantly associated with a higher level of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) in AS patients. Our results are the first to suggest that the M694V allele of the pyrin was associated with AS risk in the Chinese Han population and that this mutation may be associated with the inflammatory response in the development of AS.

Familial mediterranean fever: a fascinating model of inherited autoinflammatory disorder

BACKGROUND

Familial Mediterranean fever (FMF) is a rare inherited autosomal recessive autoinflammatory disorder characterized by recurrent and self-limited episodes of fever and painful serositis, lasting 1-3 days. FMF occurs almost exclusively among ethnic groups of the Mediterranean basin, although cases have also been found in Japan and Korean populations. Diagnosis is based on clinical features, response to colchicine and genetic analysis. Novel drugs are emerging, allowing better management of colchicine-resistant/colchicine-intolerant patients. This review aims to attract the attention of the readers on differential diagnosis and management of patients with FMF.

METHODS

The current state-of-the-art on FMF is outlined, with respect to epidemiological, genetic, pathophysiological and therapeutic characteristics, based on critical analysis of solid scientific literature.

RESULTS

FMF is more frequent than it was thought before. The phenotypic expression of M694V is more severe than that of V726A. Patients with M694V/M694V homozygosity are exposed to a higher risk of developing renal amyloidosis, arthritis, dermatologic and oral lesions, higher fever and more frequent painful attacks. Life-long therapy with colchicine (1·0-2·4 mg/day) is effective and safe to prevent recurrent attacks and renal amyloidosis and to reverse proteinuria. In nonresponder patients, alternative novel approaches include interleukin-1 receptor antagonist anakinra and the interleukin-1 decoy receptor rilonacept.

CONCLUSIONS

The prognosis of FMF is normal if AA amyloidosis is prevented. Colchicine remains the first-line therapy to treat pain and prevent amyloidosis. A follow-up should include clinical evaluation, therapeutic adjustments, measurement of serum amyloid A and proteinuria.

Gene hunting in autoinflammation

Steady progress in our understanding of the genetic basis of autoinflammatory diseases has been made over the past 16 years. Since the discovery of the familial Mediterranean fever gene MEFV (also known as marenostrin) in 1997, 18 other genes responsible for monogenic autoinflammatory diseases have been identified to date. The discovery of these genes was made through the utilisation of many genetic mapping techniques, including next generation sequencing platforms. This review article clearly describes the gene hunting approaches, methods of data analysis and the technological platforms used, which has relevance to all those working within the field of gene discovery for Mendelian disorders.

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.

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.

Familial Mediterranean fever-associated mutation pyrin E148Q as a potential risk factor for multiple sclerosis

BACKGROUND

Familial Mediterranean fever (FMF) is an inherited autoinflammatory disease caused by mutations in the MEFV gene and characterized by recurrent febrile polyserositis. A possible association of FMF and multiple sclerosis (MS) has been suggested in cohorts from Turkey and Israel.

OBJECTIVE

The objective of this study was to investigate the prevalence of MEFV mutations in subjects with MS and in controls in Germany.

METHODS

One-hundred and fifty seven MS patients with at least one symptom or without symptoms suggestive of FMF from our outpatient clinic were investigated for mutations in exons 2, 3, and 10 of the MEFV gene (group 1). 260 independent MS patients (group 2) and 400 unrelated Caucasian controls (group 3) were screened selectively for the low-penetrance pyrin mutations E148Q and K695R RESULTS: In group 1, 19 MS patients (12.1%) tested positive for a mutation in the MEFV gene, mainly the E148Q (n=7) substitution. Fifteen of the 19 mutation-positive individuals reported at least one symptom suggestive of FMF. In three cases, we could identify additional family members with MS. In these pedigrees, the E148Q exchange co-segregated with MS (p=0.026). Frequencies of the pyrin E148Q and K695R mutations were not statistically different between MS group 2 and controls but they occurred with a surprisingly high frequency in the German population.

CONCLUSION

The MEFV gene appears to be another immunologically relevant gene locus which contributes to MS susceptibility. In particular, the pyrin E148Q mutation, which co-segregated with disease in three MS families, is a promising candidate risk factor for MS that should be further explored in larger studies.

Pitfalls in familial mediterranean fever: acute intestinal strangulation/obstruction due to primary adhesions

Familial Mediterranean Fever (FMF) presents in 90% of patients with painful attacks of peritoneal inflammation, which may mimic an acute surgical abdomen. These episodes characteristically resolve spontaneously within 72 hours. However, recurrent episodes of primary peritonitis may lead to the development of primary intraperitoneal adhesions, even in the absence of previous abdominal surgery. When an atypical bout of pain fails to resolve spontaneously and rapidly, the surgeon must consider the diagnosis of intestinal obstruction due to an adhesive band with the associated risk of strangulation with bowel necrosis. In this case report, we describe this rare but classical presentation of FMF for which any delay in diagnosis or treatment may result in severe morbidity.

Familial Mediterranean fever (FMF) and multiple sclerosis: an association study in one of the world's largest FMF cohorts

BACKGROUND AND PURPOSE

  To describe and characterize the association between familial Mediterranean fever (FMF) and multiple sclerosis (MS).

METHODS

  The patient registry of The National Center for FMF was screened for the coexistence of FMF and MS. Tel-Hashomer criteria were used for the diagnosis of FMF, and FMF severity was evaluated, using the simplified FMF severity scale. McDonald criteria were used for the diagnosis of MS, and neurologic disability was measured using the expanded disability status scale (EDSS).

RESULTS

  We identified nine patients, affected with both FMF and MS. The onset of the FMF averaged 15.6 (3-37) years. Most patients suffered from abdominal and joint attacks, and 50% of the patients sustained a moderate to severe FMF. The onset of the MS was at an average age of 31.6 (17-50) years. Neurologic manifestations varied individually, without a dominant deficit, and the course was in a relapsing-remitting pattern in most. The median EDSS was in general of low score (3.0), apart from the patients who were homozygous for the M694V mutation, in whom the MS was more severe. Based on our case series, the frequency of MS in our FMF population is 0.075%, twice higher the expected rate in the general population (P=0.0057).

CONCLUSIONS

  Multiple sclerosis is more common in FMF than in the general Israeli population. Homozygosity for the M694V MEFV mutation may aggravate the phenotype of MS and predispose FMF patients to develop MS.

Arterial Distensibility in Chronic Inflammatory Rheumatic Disorders

The pulse wave velocity (PWV), as an indicator of arterial distensibility, may play an important role in the stratification of patients based on the cardiovascular risk. PWV inversely correlates with arterial distensibility and relative arterial compliance. Decreased arterial distensibility alters arterial blood pressure and flow dynamics, and disturbes coronary perfusion. Systemic immune and inflammatory diseases, such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) are associated with increased morbidity and mortality, predominantly due to adverse cardiovascular events. Systemic inflammation in these disorders may alter arterial compliance and arterial distensibility and, through this effect, lead to accelerated atherosclerosis. We have demonstrated an increase in the carotid-femoral (aortic) PWV that is a technique in which large artery elasticity is assessed from analysis of the peripheral arterial waveform, in patients with chronic inflammatory conditions such as RA, SLE, familial Mediterranean fever (FMF), Wegener’s granulomatosis (WG), sarcoidosis, psoriasis and psoriatic arthritis except Behçet’s disease (BD). In this review, the issue of arterial stiffness in RA, SLE, as well as WG, psoriasis, FMF, BD, sarcoidosis, systemic sclerosis (SS) and Takayasu's arteritis (TA) is overviewed.

Arterial distensibility in chronic inflammatory rheumatic disorders

The pulse wave velocity (PWV), as an indicator of arterial distensibility, may play an important role in the stratification of patients based on the cardiovascular risk. PWV inversely correlates with arterial distensibility and relative arterial compliance. Decreased arterial distensibility alters arterial blood pressure and flow dynamics, and disturbes coronary perfusion. Systemic immune and inflammatory diseases, such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) are associated with increased morbidity and mortality, predominantly due to adverse cardiovascular events. Systemic inflammation in these disorders may alter arterial compliance and arterial distensibility and, through this effect, lead to accelerated atherosclerosis. We have demonstrated an increase in the carotid-femoral (aortic) PWV that is a technique in which large artery elasticity is assessed from analysis of the peripheral arterial waveform, in patients with chronic inflammatory conditions such as RA, SLE, familial Mediterranean fever (FMF), Wegener's granulomatosis (WG), sarcoidosis, psoriasis and psoriatic arthritis except Behçet's disease (BD). In this review, the issue of arterial stiffness in RA, SLE, as well as WG, psoriasis, FMF, BD, sarcoidosis, systemic sclerosis (SS) and Takayasu's arteritis (TA) is overviewed.

[Molecular diagnostics of hereditary fever syndromes. Familial Mediterranean fever (FMF), hyperimmunoglobulin D syndrome (HIDS), tumor necrosis factor receptor-associated periodic syndrome (TRAPS), cryopyrin-associated periodic syndrome (CAPS: FCAS, MWS, NOMID/CINCA)]

Periodic episodes of fever and inflammation can have a genetic origin. Nowadays, the identification of the causative genetic variants in the majority of cases allows molecular genetic confirmation of the clinical diagnosis, which enables approaches with specific drug treatment and improves patient compliance as well as genetic counseling. Besides a detailed clinical examination a medical history including family history and an assessment of the ethnic origin are required. In order to make genetic testing straightforward and cost effective an iterative procedure should be followed which should include, in addition to clinical data, the frequencies of causative mutations in the various gene segments involved.

Genetic variation in the familial Mediterranean fever gene (MEFV) and risk for Crohn's disease and ulcerative colitis

BACKGROUND AND AIMS

The familial Mediterranean fever (FMF) gene (MEFV) encodes pyrin, a major regulator of the inflammasome platform controlling caspase-1 activation and IL-1beta processing. Pyrin has been shown to interact with the gene product of NLRP3, NALP3/cryopyrin, also an important active member of the inflammasome. The NLRP3 region was recently reported to be associated with Crohn's disease (CD) susceptibility. We therefore sought to evaluate MEFV as an inflammatory bowel disease (IBD) susceptibility gene.

METHODOLOGY AND RESULTS

MEFV colonic mucosal gene expression was significantly increased in experimental colitis mice models (TNBS p<0.0003; DSS p<0.006), in biopsies from CD (p<0.02) and severe ulcerative colitis (UC) patients (p<0.008). Comprehensive genetic screening of the MEFV region in the Belgian exploratory sample set (440 CD trios, 137 UC trios, 239 CD cases, 96 UC cases, and 107 healthy controls) identified SNPs located in the MEFV 5' haplotype block that were significantly associated with UC (rs224217; p = 0.003; A allele frequency: 56% cases, 45% controls), while no CD associations were observed. Sequencing and subsequent genotyping of variants located in this associated haplotype block identified three synonymous variants (D102D/rs224225, G138G/rs224224, A165A/rs224223) and one non-synonymous variant (R202Q/rs224222) located in MEFV exon 2 that were significantly associated with UC (rs224222: p = 0.0005; A allele frequency: 32% in cases, 23% in controls). No consistent associations were observed in additional Canadian (256 CD trios, 91 UC trios) and Scottish (495 UC, 370 controls) sample sets. We note that rs224222 showed marginal association (p = 0.012; G allele frequency: 82% in cases, 70% in controls) in the Canadian sample, but with a different risk allele. None of the NLRP3 common variants were associated with UC in the Belgian-Canadian UC samples and no significant interactions were observed between NLRP3 and MEFV that could explain the observed flip-flop of the rs224222 risk allele.

CONCLUSION

The differences in association levels observed between the sample sets may be a consequence of distinct founder effects or of the relative small sample size of the cohorts evaluated in this study. However, the results suggest that common variants in the MEFV region do not contribute to CD and UC susceptibility.

Horror autoinflammaticus: the molecular pathophysiology of autoinflammatory disease (*)

The autoinflammatory diseases are characterized by seemingly unprovoked episodes of inflammation, without high-titer autoantibodies or antigen-specific T cells. The concept was proposed ten years ago with the identification of the genes underlying hereditary periodic fever syndromes. This nosology has taken root because of the dramatic advances in our knowledge of the genetic basis of both mendelian and complex autoinflammatory diseases, and with the recognition that these illnesses derive from genetic variants of the innate immune system. Herein we propose an updated classification scheme based on the molecular insights garnered over the past decade, supplanting a clinical classification that has served well but is opaque to the genetic, immunologic, and therapeutic interrelationships now before us. We define six categories of autoinflammatory disease: IL-1beta activation disorders (inflammasomopathies), NF-kappaB activation syndromes, protein misfolding disorders, complement regulatory diseases, disturbances in cytokine signaling, and macrophage activation syndromes. A system based on molecular pathophysiology will bring greater clarity to our discourse while catalyzing new hypotheses both at the bench and at the bedside.

Laboratory tests in the diagnosis and follow-up of pediatric rheumatic diseases: an update

OBJECTIVES

We reviewed the literature to evaluate the role of common laboratory tests and to examine the recent progress in the laboratory diagnosis of pediatric rheumatic diseases.

METHODS

We used the PubMed database (1950-2008) to search for the keywords "laboratory," "erythrocyte sedimentation rate" (ESR), "C-reactive protein" (CRP), "blood cytology," "procalcitonin" (PCT), "complement system," "ferritin," "antistreptolysin O titer" (ASO), "autoantibodies," "genetic studies," in conjunction with "rheumatic disease in children" and "pediatric autoimmune diseases." All relevant original and review articles in English were reviewed as well as textbooks of pediatric rheumatology.

RESULTS

Laboratory tests (ESR, CRP, blood cytology, complement system, ferritin, ASO titer) play an important role in confirming a diagnosis and in the follow-up of rheumatic diseases in the pediatric age group. The ESR is probably the most widely measured index of the acute phase response. Measurement of CRP is very useful in the rapid diagnosis of infection as a progressive increase can be shown in the first 48 hours. Also, the subsequent fall in serum CRP concentration on resolution of inflammation is useful for monitoring the efficacy of treatment. In chronic diseases, a combination of CRP and ESR may provide the most useful information. Cytopenia and different forms of anemia can be encountered in many rheumatic diseases: they can be related to disease activity or to therapeutic side effects. Determination of complement levels (C3 and/or C4) is useful in the follow-up of systemic lupus erythematosus (SLE) and membranoproliferative glomerulonephritis. Ferritin is a laboratory hallmark of primary and secondary hemophagocytic lymphohistiocytosis. ASO titer should be obtained to confirm a diagnosis of acute rheumatic fever; other important antibody markers of streptococcal infection include antihyaluronidase, antideoxyribonuclease B, and antistreptokinase antibodies. We also found that, in the pediatric age, the main indication for synovial fluid analysis is suspected joint infection. Antinuclear antibodies, anti-Smith antigen, and anti-double-stranded DNA antibodies are important in the diagnosis of SLE, are useful prognostic markers, and facilitate clinical and treatment follow-up. Anti-SSA/Ro and anti-SSB/La antibodies are associated with Sjögren's syndrome and congenital heart block, while the anti-U1 small nuclear ribonucleoprotein antibodies show high specificity for mixed connective tissue disease. Repetitive spontaneous abortions, thrombocytopenia, and many types of venous or arterial thrombosis are associated with antiphospholipid antibodies. The presence of cytoplasmic antineutrophil antibodies is essential in the diagnosis of Wegener granulomatosis. The discovery of underlying single causative gene defects led to the identification of several autoinflammatory diseases, a group of genetic disorders characterized by recurrent attacks of inflammation (hereditary periodic fever syndromes). These include familial Mediterranean fever due to mutations in the Mediterranean fever (MEFV) gene, hyperimmunoglobulinemia D syndrome due to mutations in the MK gene for mevalonate kinase, cryopyrinopathies such as Muckle-Wells syndrome or neonatal-onset multisystemic inflammatory disease (neonatal-onset multisystemic inflammatory disease or chronic infantile neurological cutaneous and articular (CINCA)) associated with cold-induced autoinflammatory syndrome 1 gene mutations, and tumor necrosis factor receptor-associated periodic syndrome due to mutation of TNF receptor I gene.

CONCLUSIONS

Laboratory investigations play an important role in the diagnosis and follow-up of inflammatory rheumatic diseases in children. A good history and a complete physical examination are the best screening tests. Routine laboratory tests are useful to confirm a suspected diagnosis, to assess disease activity, and to measure the response and toxicity to treatment. Only a few tests represent diagnostic criteria such as antinuclear antibodies and anti-double-stranded DNA in SLE or cytoplasmic antineutrophil cytoplasmic autoantibodies in Wegener's granulomatosis. Recent advances in molecular genetics have impacted diagnosis, pathogenesis, and treatment in genetic fever syndromes.

Effect of Helicobacter pylori infection and eradication therapy on interleukin-6 levels in patients with Familial Mediterranean Fever

It is being questioned if Helicobacter pylori infection, which causes a chronic inflammatory response, can increase the frequency and severity of attacks in patients with Familial Mediterranean Fever (FMF) and if the impact of inflammatory response can be diminished by eradication of the infection. To evaluate if there is difference in interleukin (IL)-6 levels of H. pylori-positive and -negative patients both before and during FMF attacks; if there is a change in IL-6 levels following successful eradication treatment; and if MEFV gene mutations have an effect on IL-6 levels. IL-6 levels were evaluated in 47 FMF patients before and during FMF attacks. Genetic testing to determine M694V, M694I, E148Q, V726V, M680I mutations was also performed in all patients. IL-6 levels were also determined after successful eradication of the infection in H. pylori-positive patients. IL-6 levels were compared in H. pylori-positive and -negative patients, and before and after eradication treatment in patients who cleared the infection. Number of patients in tested mutation groups was not enough to compare IL-6 levels in these groups. Thirty-four patients (73.9%) were H. pylori-positive. Before FMF attack there was no statistically significant difference in IL-6 levels of H. pylori-positive and -negative groups. IL-6 levels were significantly higher in both groups during the attacks than before the attacks (p < 0.05). There was a statistically significant decline in IL-6 levels both before and during FMF attacks, following eradication therapy in patients who cleared the infection (p < 0.05). In patients with homozygous M694V mutation, IL-6 levels before and during the FMF attacks were not significantly different in H. pylori-positive and -negative groups, despite a much lower level found in H. pylori-negative group (p > 0.05). Comparisons were not performed in other mutation groups because of small number of patients in each group. C-reactive protein (CRP) and fibrinogen levels were not significantly different between the groups (p > 0.05). We believe that the observation of IL-6 levels are lower both before and during FMF attacks both in H. pylori-negative patients and in patients who cleared the infection after eradication therapy is very important in the determination of the role of eradication of H. pylori on decreasing the frequency and severity of FMF attacks. As for today, the correlation between H. pylori infection and FMF seems unlikely; however, studies evaluating the interaction of cytokines in both diseases and their relations and roles will be needed to reach better conclusions.

Periodic fever syndromes: a diagnostic challenge for the allergist

The objective was to present a case of periodic fever with aphthous stomatitis, pharyngitis and cervical adenitis (PFAPA), summarize the medical literature on PFAPA, review the differential diagnosis and suggest a diagnostic approach to periodic fevers in children. A PubMed search was conducted for all case reports and series of patients with PFAPA. The references of these papers yielded further case reports. Review articles or large case series were used for sources of information regarding the other periodic fever and autoinflammatory syndromes. All cases reported as PFAPA were included in the review, even though a few of the cases may not have been accurately diagnosed. The periodic fever and autoinflammatory syndromes of childhood are a group of diseases that cause repeated febrile illnesses with various associated symptoms. Except for PFAPA, each of these diseases is caused by a known genetic mutation. Effective treatment options and long-term prognosis varies among these syndromes. Children with periodic fever or autoinflammatory syndromes sometimes present to an Allergy/Immunology clinic for immunologic evaluation. It is important for the Allergy/Immunology specialist to be familiar with the clinical presentation, diagnostic approach and treatment of these conditions.