MEFV gene polymorphisms and TNFRSF1A mutation in patients with inflammatory myopathy with abundant macrophages

Inflammatory myopathy with abundant macrophages (IMAM) has recently been proposed as a new clinical condition. Although IMAM shares certain similarities with other inflammatory myopathies, the mechanisms responsible for this condition remain unknown. Patients with familial Mediterranean fever (FMF) and tumour necrosis factor receptor-associated periodic syndrome (TRAPS) also often develop myalgia. We therefore investigated the polymorphisms or mutations of MEFV and TNFRSF1A genes in patients with IMAM to identify their potential role in this condition. We analysed the clinical features of nine patients with IMAM and sequenced exons of the MEFV and TNFRSF1A genes. The patients with IMAM had clinical symptoms such as myalgia, muscle weakness, erythema, fever and arthralgia. Although none of the patients were diagnosed with FMF or TRAPS, seven demonstrated MEFV polymorphisms (G304R, R202R, E148Q, E148Q-L110P and P369S-R408Q), and one demonstrated a TNFRSF1A mutation (C43R). These results suggest that MEFV gene polymorphisms and TNFRSF1A mutation are susceptibility and modifier genes in IMAM.     

Unexpected high frequency of P46L TNFRSF1A allele in sub-Saharan West African populations

TNF receptor-associated periodic syndrome (TRAPS) is an autosomal dominant disorder characterized by recurrent attacks of fever and serositis. To date, more than 30 mutations have been reported in TNFRSF1A, the responsible gene. In Caucasian populations, the P46L (c.224C>T) TNFRSF1A sequence variation is considered as a low-penetrance mutation because its allele frequency is similar in patients and controls ( approximately 1%). Whereas the spectrum of TNFRSF1A gene mutations has been well established in Caucasian and several Mediterranean populations, it remains unknown in sub-Saharan African populations. In this study, we found an unexpected high P46L allele frequency ( approximately 10%) in two groups from West Africa - a group of 145 patients with sickle cell anaemia and a group of 349 healthy controls. These data suggest that the P46L variant is rather a polymorphism than a TRAPS causative mutation. We propose that the P46L high frequency in West African populations could be explained by some biological advantage conferred to carriers.     

Tumour necrosis factor receptor-associated periodic syndrome (TRAPS): State of the art and future perspectives

Tumor necrosis factor (TNF) receptor-associated periodic syndrome (TRAPS) is an autosomal dominant autoinflammatory disorder characterized by periodic fever episodes, arthralgia, myalgia, abdominal pain, serositis, and skin rash. TRAPS is caused by mutations in the gene encoding the TNF Receptor Super Family 1A (TNFRSF1A) on chromosome 12p13. The identification of TNFRSF1A mutations as the genetic cause of TRAPS coincided with the wider use of biological agents in medicine and raised the possibility that blocking TNF could potentially represent the primary therapeutic goal in TRAPS, thus disclosing new treatment choices for this complex disease. Anti-TNF therapy in TRAPS has been based on etanercept, a recombinant human TNFR (p75)-Fc fusion protein comprising two receptors linked by an IgG₁ Fc fragment. However a decrease in responsiveness to etanercept over time has been described, and it may be due to a non-specific action of etanercept in TRAPS; its efficacy may reflect ‘generic’ anti-inflammatory properties. Long-term adherence to etanercept is poor and a significant number of patients need to switch to anti-interleukin (IL)-1β therapy. In fact, the IL-1 receptor antagonist anakinra has recently been shown to prevent disease relapses both in the short- and in the long-term, and to induce a prompt and stable disease remission.     

A novel Y331X nonsense mutation in TNFRSF1A gene in two unrelated Turkish families with periodic fever syndrome

The autoinflammatory disorders differ in severity, as well as age of onset, duration, and manifestations, but they all share some common features: recurring fever peaks, inflammation of serosal membranes, musculoskeletal involvement, varying types of skin rash, amyloidosis as a sequel of the disease. TRAPS is very rare in Turkish population and we present two unrelated Turkish children with similar clinical phenotypes and laboratory findings related with autoinflammatory disorders and with novel p. Y331X mutation in TNFRSF1A gene. Both of the patients were male and they had recurrent fever without abdominal pain and arthralgia. Full cDNA and exon–intron binding regions of TNFRSF1A, MEFV, MVK, CIAS1 genes were analysed by direct DNA sequencing methods in order to differentiate TRAPS, FMF, HIDS, CINCA/MWS/FCAS respectively. We screened ten exons of TNFRSF1A gene, and detected a heterozygous c.1080C>G nucleotide substitution in exon 10 in both of the unrelated patients, resulting p.Y360X nonsense (protein truncated) mutation. According to classical TNFRSF1A gene nomenclature and the agreement of 30th amino acid as the first one, it is accepted as p.Y331X. It was interesting to determine same mutations in fathers of two patients. In one of the cases, E148Q heterozygous mutation, which is one of the disease-causing mutations of MEFV gene, was detected. No nucleotide substitution was identified in exon and exon–intron splicing regions encoding 396 amino acid of MVK gene in both of the patients. In CIAS1 gene, two different nucleotide substitutions resulting synonymous amino acid mutation were detected in exon 3: c.[732G>A] and c.[786A>G] nucleotide substitutions and compatible p.A242A (according to c.DNA p.A244A) and p.R260R (according to c.DNA p.R262R) synonymous amino acid mutations. These nucleotide substitutions were also detected in parents and were reported to be normal variations in Turkish population. In conclusion, in Turkish patients, with dominantly inherited recurrent fever, TRAPS is a diagnosis worthy of attention and novel mutations have to be reported with phenotype associations.     

TNF receptor-associated periodic syndrome (TRAPS) in Japan: clinical characterization, pathogenesis, diagnostic criteria, and treatment]

TNF receptor-associated periodic syndrome (TRAPS) is an autosomal dominant inherited disease characterized by prolonged episodes of periodic fever and localized inflammation. The hypothetical pathogenesis of TRAPS is defective TNF receptor 1 (TNFRSF1A) shedding from cell membranes in response to a stimulus including TNFalpha. This mechanism has recently been shown to account for a minor population of TRAPS patients and other mechanisms are reported to explain the disease, such as resistance to apoptosis, TNFRSF1A internalization, or TNFRSF1A misfolding and aggregation, leading to NF-kappaB activation and apoptosis. Until now 15 TRAPS patients from 5 pedigree including 5 different mutations (C30R, C30Y, T61I, C70S, C70G) had been reported in Japan. There were many sporadic cases of TRAPS without TNFRSF1A mutation in our epidemiological study. In this issue, we described the clinical characterization, pathogenesis, diagnostic criteria, and treatment of TRAPS according to our case and literature.     

TNFRSF1A mutations and autoinflammatory syndromes

The autoinflammatory syndromes are systemic disorders characterized by apparently unprovoked inflammation in the absence of high-titer autoantibodies or antigen-specific T lymphocytes. One such illness, TNF-receptor-associated periodic syndrome (TRAPS), presents with prolonged attacks of fever and severe localized inflammation. TRAPS is caused by dominantly inherited mutations in TNFRSF1A (formerly termed TNFR1), the gene encoding the 55 kDa TNF receptor. All known mutations affect the first two cysteine-rich extracellular subdomains of the receptor, and several mutations are substitutions directly disrupting conserved disulfide bonds. One likely mechanism of inflammation in TRAPS is the impaired cleavage of TNFRSF1A ectodomain upon cellular activation, with diminished shedding of the potentially antagonistic soluble receptor. Preliminary experience with recombinant p75 TNFR-Fc fusion protein in the treatment of TRAPS has been favorable.     

Hyper IgD syndrome (HIDS) associated with in vitro evidence of defective monocyte TNFRSF1A shedding and partial response to TNF receptor blockade with etanercept

Hereditary periodic fever syndromes comprise a group of distinct disease entities linked by the defining feature of recurrent febrile episodes. Hyper IgD with periodic fever syndrome (HIDS) is caused by mutations in the mevalonate kinase (MVK) gene. The mechanisms by which defects in the MVK gene cause febrile episodes are unclear and there is no uniformly effective treatment. Mutations of the TNFRSF1A gene may also cause periodic fever syndrome (TRAPS). Treatment with the TNFR-Fc fusion protein, etanercept, is effective in some patients with TRAPS, but its clinical usefulness in HIDS has not been reported. We describe a 3-year-old boy in whom genetic screening revealed a rare combination of two MVK mutations producing clinical HIDS as well as a TNFRSF1A P46L variant present in about 1% of the population. In vitro functional assays demonstrated reduced receptor shedding in proband's monocytes. The proband therefore appears to have a novel clinical entity combining Hyper IgD syndrome with defective TNFRSF1A homeostasis, which is partially responsive to etanercept.     

Functional analysis of a novel G87V TNFRSF1A mutation in patients with TNF receptor-associated periodic syndrome

Tumor necrosis factor (TNF) receptor-associated periodic syndrome (TRAPS) is an autoinflammatory disease that is caused by heterozygous mutations in the TNFRSF1A gene. Although more than 150 TNFRSF1A mutations have been reported to be associated with TRAPS phenotypes only a few, such as p.Thr79Met (T79M) and cysteine mutations, have been functionally analyzed. We identified two TRAPS patients in one family harboring a novel p.Gly87Val (G87V) mutation in addition to a p.Thr90Ile (T90I) mutation in TNFRSF1A. In this study, we examined the functional features of this novel G87V mutation. In-vitro analyses using mutant TNF receptor 1 (TNF-R1)-over-expressing cells demonstrated that this mutation alters the expression and function of TNF-R1 similar to that with the previously identified pathogenic T79M mutation. Specifically, cell surface expression of the mutant TNF-R1 in transfected cells was inhibited with both G87V and T79M mutations, whereas the T90I mutation did not affect this. Moreover, peripheral blood mononuclear cells (PBMCs) from TRAPS patients harboring the G87V and T90I mutations showed increased mitochondrial reactive oxygen species (ROS). Furthermore, the effect of various Toll-like receptor (TLR) ligands on inflammatory responses was explored, revealing that PBMCs from TRAPS patients are hyper-responsive to TLR-2 and TLR-4 ligands and that interleukin (IL)-8 and granulocyte–macrophage colony-stimulating factor (GM-CSF) are likely to be involved in the pathogenesis of TRAPS. These findings suggest that the newly identified G87V mutation is one of the causative mutations of TRAPS. Our findings based on unique TRAPS-associated mutations provide novel insight for clearer understanding of inflammatory responses, which would be basic findings of developing a new therapeutic and prophylactic approach to TRAPS.     

Allelic variants in genes associated with hereditary periodic fever syndromes as susceptibility factors for reactive systemic AA amyloidosis

We investigated the hypothesis that low-penetrance mutations in genes (TNFRSF1A, MEFV and NALP3/CIAS1) associated with hereditary periodic fever syndromes (HPFs) might be risk factors for AA amyloidosis among patients with chronic inflammatory disorders, including rheumatoid arthritis (RA), juvenile idiopathic arthritis (JIA), Crohn's disease, undiagnosed recurrent fevers and HPFs themselves. Four of 67 patients with RA plus amyloidosis had MEFV variants compared with none of 34 RA patients without amyloid (P value=0.03). The E148Q variant of MEFV was present in two of the three patients with TNF receptor-associated periodic syndrome (TRAPS) complicated by amyloid in two separate multiplex TRAPS families containing 5 and 16 affected members respectively, and the single patient with Muckle-Wells syndrome who had amyloidosis was homozygous for this variant. The R92Q variant of TNFRSF1A was present in two of 61 JIA patients with amyloidosis, and none of 31 nonamyloidotic JIA patients. No HPF gene mutations were found in 130 healthy control subjects. Although allelic variants in HPFs genes are not major susceptibility factors for AA amyloidosis in chronic inflammatory disease, low-penetrance variants of MEFV and TNFRSF1A may have clinically significant proinflammatory effects.     

Tumor necrosis factor receptor-associated periodic syndrome (TRAPS) in a Dutch family: evidence for a TNFRSF1A mutation with reduced penetrance

Mutations of the tumor necrosis factor receptor 1 (TNFRSF1A) gene underly susceptibility to a subset of autosomal dominant recurrent fevers (ADRFs). We report on a two-generation six-member Dutch family in which a novel R92P mutation and reduced plasma TNFRSF1A levels were found in all the children, including two who are unaffected. However, only the daughter proband and father exhibited a typical TNF-receptor associated periodic syndrome (TRAPS) phenotype. PCR-RFLP analysis revealed that the mutation was not present in 120 control chromosomes from unaffected Dutch individuals. As this R92P mutation is present in two unaffected carriers it appears to be less penetrant than previously reported TNFRSF1A mutations involving cysteine residues in the extracellular domains.     

Role of tumour necrosis factor (TNF)-α and TNFRSF1A R92Q mutation in the pathogenesis of TNF receptor-associated periodic syndrome and multiple sclerosis

It has long been known that tumour necrosis factor (TNF)/TNFRSF1A signalling is involved in the pathophysiology of multiple sclerosis (MS). Different genetic and clinical findings over the last few years have generated renewed interest in this relationship. This paper provides an update on these recent findings. Genome-wide association studies have identified the R92Q mutation in the TNFRSF1A gene as a genetic risk factor for MS (odds ratio 1·6). This allele, which is also common in the general population and in other inflammatory conditions, therefore only implies a modest risk for MS and provides yet another piece of the puzzle that defines the multiple genetic risk factors for this disease. TNFRSF1A mutations have been associated with an autoinflammatory disease known as TNF receptor-associated periodic syndrome (TRAPS). Clinical observations have identified a group of MS patients carrying the R92Q mutation who have additional TRAPS symptoms. Hypothetically, the co-existence of MS and TRAPS or a co-morbidity relationship between the two could be mediated by this mutation. The TNFRSF1A R92Q mutation behaves as a genetic risk factor for MS and other inflammatory diseases, including TRAPS. Nevertheless, this mutation does not appear to be a severity marker of the disease, neither modifying the clinical progression of MS nor its therapeutic response. An alteration in TNF/TNFRS1A signalling may increase proinflammatory signals; the final clinical phenotype may possibly be determined by other genetic or environmental modifying factors that have not yet been identified.     

Identification of a novel mevalonate kinase gene mutation in combination with the common MVK V377I substitution and the low-penetrance TNFRSF1A R92Q mutation

The hyperimmunoglobulinemia D and periodic fever syndrome (HIDS) is an autosomal recessively inherited autoinflammatory disease caused by mutations in the mevalonate kinase (MVK) gene on chromosome 12q24, which lead to a depressed enzymatic activity of mevalonate kinase (MK). TNF-receptor associated periodic syndrome (TRAPS), on the other hand, is the most frequent autosomal dominantly inherited periodic fever syndrome due to mutations in exons 2-4 and 6 of the TNFRSF1A gene on chromosome 12p13.2. We describe a girl with heterozygosity for the common MVK V377I mutation and for a novel T(1132) --> C transition, leading to the exchange of serine (TCC) by proline (CCC) at amino-acid position 378. Interestingly, our patient presented only with mild clinical features typical of HIDS and slightly increased immunoglobulin D levels, but a distinctly diminished MK activity. The girl was also heterozygous for the TNFRSF1A R92Q low-penetrance mutation, which may have significant proinflammatory effects. However, at the time of presentation, the patient had no TRAPS-associated symptoms.     

Autosomal dominant familial periodic fever patient with a missense variant c.215G>A (p.Cys72Tyr) in TNFRSF1A gene presenting as neutrophilia

Familial periodic fever (FPF) is an uncommonly diagnosed autosomal dominant disorder caused by a genetic alteration in the TNFRSF1A gene. These patients usually present with fever which is usually under-investigated and under-diagnosed. In untreated cases, amyloidosis is a frequent complication. We present a 24 years male who had a history of fever from childhood, however, remained undiagnosed short of genetic testing. He has recurrent episodes of fever. During the episodes of fever, he was found to have leukocytosis (total leukocyte count- 25.7 x10^9/L) and neutrophilia (absolute neutrophil count- 22.7 x10^9/L) both of which came back to normal limits as the fever subsided. On further evaluation for neutrophilia, the exclusion of common causes of neutrophilia was done. Next-generation sequencing detected a missense variant in TNFRSF1A: c.215G > A (p.Cys72Tyr) which was confirmed by Sanger sequencing. This variant has been described in the literature in anecdotal cases of FPF. This is a first case report from the Indian subcontinent reporting TNFRSF1A: c.215G > A (p.Cys72Tyr) variant in a patient of FPF. Short of genetic testing, the fever would remain a diagnostic dilemma in this patient. This report highlights the importance of targeted resequencing in clinching diagnosis in such patients.     

Canakinumab for the treatment of TNF-receptor associated periodic syndrome

Introduction: TNF-receptor-associated periodic syndrome is an autoinflammatory disorder caused by mutations in TNF receptor superfamily 1A gene. The molecular pathogenesis of TRAPS remains unclear; it is known that a key role is played by mutations in TNFRSF1A that induce the hypersecretion of pro-inflammatory cytokines as well as IL-1β, resulting in uncontrolled inflammatory reactions. Furthermore, TNFRSF1A gene mutations result in intracellular stress ultimately leading to increased production of interleukin-1β, but the exact mechanism referred to in the connection between TNFRSF1A mutation and increased release of IL-1β, is still under study. This explains why IL-1 inhibition treatment can be effective in treating TRAPS patients. The purpose of this review is to discuss the safety and efficacy of canakinumab, a high-affinity human monoclonal anti IL-1β antibody.

Areas covered: The data obtained from case reports, case series, Phase II study and a phase III randomized, double-blind, placebo controlled trial have been analyzed. Efficacy and safety profiles of canakinumab are discussed.

Expert commentary: Was discussed an overview of treatment options in TRAPS patients. The understanding of pathogenesis of TNF-receptor-associated periodic syndrome led to realize why TRAPS patients respond to IL-1 inhibition. Canakinumab became approved for the treatment in TRAPS patients very recently.     

Novel mutations in TNFRSF1A in patients with typical tumor necrosis factor receptor-associated periodic syndrome and with systemic lupus erythematosus in Japanese

Molecular defects of TNFRSF1A was investigated in members of a family presenting with typical phenotypes of tumor necrosis factor receptor-associated periodic syndrome (TRAPS) and in patients with the autoimmune disorders, systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). Genomic DNA from the members of a family with typical TRAPS, as well as from 100 patients with SLE, 100 patients with RA and 100 healthy individuals, was studied for mutations in exons 2, 3 and 4 of the TNFRSF1A gene. All individuals were Japanese. Three novel missense mutations were identified in the TNFRSF1A. The C70G mutation was identified in family members with typical TRAPS, which was the second case in eastern Asian population. In addition, the T61I and R104Q mutations were each identified in 2 of the 100 SLE patients. The T61I mutation was identified in one of the 100 healthy individuals. No mutations were identified in the 100 RA patients. Functional analysis revealed that PMA-induced shedding of TNFRSF1A from PBMCs was impaired in a patient carrying T61I. A larger scale of study will clarify whether these two mutations, T61I and R104Q, are associated with chronic inflammatory disorders, such as SLE, or not.     

Allogeneic Bone Marrow Transplantation Appears to Ameliorate IgA Nephropathy in a Patient with X-linked Thrombocytopenia

Wiskott-Aldrich syndrome (WAS) is caused by a mutation in the WAS gene, and it is clinically characterized by the triad of thrombocytopenia, eczema and immunodeficiency. X-linked thrombocytopenia (XLT), which is a clinically mild form of WAS, is also caused by a WAS gene mutation. Patients with WAS/XLT sometimes also have autoimmune diseases such as IgA nephropathy. Progression of IgA nephropathy may lead to chronic renal failure with a poor prognosis. Here, we describe an XLT patient who also had IgA nephropathy. The patient underwent bone marrow transplantation (BMT) because of an associated-lymphoproliferative disorder, and clinical and histological improvement in his IgA nephropathy was observed after BMT. The amount of galactose-deficient IgA in the patient’s serum markedly decreased after BMT. Therefore, immunological reconstitution might improve autoimmune diseases in patients with WAS/XLT.     

Clinical and Genetic Features of Korean Patients with Recurrent Fever and Multi-System Inflammation without Infectious or Autoimmune Evidence

Autoinflammatory disease (AID) is a newly proposed category of disorders characterized by unprovoked episodes of inflammation without any infectious or autoimmune evidence. We aimed to characterize the clinical and genetic features of patients who had recurrent fever and multi-system inflammation but remain unclassified for any established AIDs. Medical records of 1,777 patients who visited our Rheumatology Clinic between March 2009 and December 2010 were reviewed to identify those who met the following criteria; 1) presence of fever, 2) inflammation in two or more organ systems, 3) recurrent nature of fever or inflammation, 4) no evidence of infection or malignancy, 5) absence of high titer autoantibodies, and 6) failure to satisfy any classification criteria for known AIDs. Genotyping was performed for common missense variants in MEFV, NOD2/CARD15, and TNFRSF1A. A small number of patients (17/1,777, 0.95%) were identified to meet the above criteria. Muco-cutaneous and musculoskeletal features were most common, but there was a considerable heterogeneity in symptom combination. Although they did not satisfy any established classification criteria for AIDs, substantial overlap was observed between the clinical spectrum of these patients and known AIDs. According to the newly proposed Eurofever criteria for periodic fevers, eleven of them were classified as TNF receptor-associated periodic syndrome and two as mevalonate kinase deficiency. However, no examined genetic variants including those in TNFRSF1A were found in these patients. A new set of classification criteria needs to be developed and validated for Asian patients with unclassified AIDs.     

Muckle–Wells syndrome in an Indian family associated with NLRP3 mutation

Muckle — Wells syndrome (MWS) is a rare autosomal dominant disease that belongs to a group of hereditary periodic fever syndromes. It is part of the wider spectrum of the cryopyrin-associated periodic syndrome (CAPS) which has only rarely been described in non-Caucasian individuals. It is characterized by recurrent self-limiting episodes of fever, urticaria, arthralgia, myalgia and conjunctivitis from childhood. Progressive sensorineural hearing loss and amyloidosis are two late complications. MWS is caused by gain of function mutations in the NLRP3 gene, which encodes cryopyrin, a protein involved in regulating the production of proinflammatory cytokines. We report two patients with MWS in an Indian family associated with the p.D303N mutation in the NLRP3 gene. These findings promote awareness of these hereditary periodic fever syndromes as a cause for recurrent fevers from childhood in the Indian population.KEY WORDS: Hereditary periodic fever, D303N mutation, Indian family, Muckle—Wells syndrome, p.D303N mutation     

Clinical and Genetic Profile of Children with Periodic Fever Syndromes from a Single Medical Center in South East Michigan

Objective

To report a cohort of children with periodic fever syndromes (PFS) from Southeast Michigan.

Methods

A retrospective review of medical records for patients referred for periodic fever over 5 years.

Results

Sixty-six patients including 21 FMF, 15 PFAPA, four TRAPS and one patient with combined HIDS and FMF were included. In addition, 25 patients were categorized as clinical PFS (cPFS) based on their clinical features however their genetic workup was either negative or inconclusive. Majority of the patients with FMF were from Middle Eastern background (88 %), but positive family history was noted in only 55 % of cases. Mean age at diagnosis was 40.8 months with a mean delay in diagnosis of 24 months. Most common MEFV mutations were p.M694V and p.M694I. Four patients with TRAPS were from mixed European descent and age at onset of symptoms was 6, 12, 12, and 84 months respectively. TNFRSF1A sequence variants in the TRAPS patients included p.R121Q (R92Q) and p.C99G (C70G); one patient had a rare occurrence of a concurrent p.V726A/-MEFV mutation. One patient with HIDS and FMF presented with atypical overlapping PFS clinical manifestations and genetic evaluation showed a unique combination of p.I268T/p.V377I MVK mutations and p.E230K/-MEFV variant. All patients with PFAPA group were from mixed European descent, symptoms started at a mean age of 34.6 months with a mean delay in diagnosis of 23.3 months. Symptoms started during infancy in six patients. All patients fulfilled the diagnostic criteria for PFAPA. The mean age of onset of symptoms in cPFS group was 17.2 months. Empiric colchicine and glucocorticosteroids controlled flares in majority of patients with cPFS. No evidence of amyloidosis was found in this entire cohort of 66 patients after a mean of 29.2 months of follow-up.

Conclusion

PFS can present with atypical manifestations and should not be excluded based on a negative family history. Concomitant mutations in different autoinflammatory disorders genes can be present and possibly explain atypical manifestations. Various therapies may be considered even if genetic testing is inconclusive or negative.