Molecular analysis of the mevalonate kinase gene in a cohort of patients with the hyper-igd and periodic fever syndrome: its application as a diagnostic tool

The 2021 EULAR/American College of Rheumatology Points to Consider for Diagnosis, Management and Monitoring of the Interleukin-1 Mediated Autoinflammatory Diseases: Cryopyrin-Associated Periodic Syndromes, Tumour Necrosis Factor Receptor-Associated Periodic Syndrome, Mevalonate Kinase Deficiency, and Deficiency of the Interleukin-1 Receptor Antagonist

BACKGROUND

The interleukin-1 (IL-1) mediated systemic autoinflammatory diseases, including the cryopyrin- associated periodic syndromes (CAPS), tumour necrosis factor receptor-associated periodic syndrome (TRAPS), mevalonate kinase deficiency (MKD) and deficiency of the IL-1 receptor antagonist (DIRA), belong to a group of rare immunodysregulatory diseases that primarily present in early childhood with variable multiorgan involvement. When untreated, patients with severe clinical phenotypes have a poor prognosis, and diagnosis and management of these patients can be challenging. However, approved treatments targeting the proinflammatory cytokine IL-1 have been life changing and have significantly improved patient outcomes.

OBJECTIVE

To establish evidence-based recommendations for diagnosis, treatment and monitoring of patients with IL-1 mediated autoinflammatory diseases to standardise their management.

METHODS

A multinational, multidisciplinary task force consisting of physician experts, including rheumatologists, patients or caregivers and allied healthcare professionals, was established. Evidence synthesis, including systematic literature review and expert consensus (Delphi) via surveys, was conducted. Consensus methodology was used to formulate and vote on statements to guide optimal patient care.

RESULTS

The task force devised five overarching principles, 14 statements related to diagnosis, 10 on therapy, and nine focused on long-term monitoring that were evidence and/or consensus-based for patients with IL-1 mediated diseases. An outline was developed for disease-specific monitoring of inflammation-induced organ damage progression and reported treatments of CAPS, TRAPS, MKD and DIRA.

CONCLUSION

The 2021 EULAR/American College of Rheumatology points to consider represent state-of-the-art knowledge based on published data and expert opinion to guide diagnostic evaluation, treatment and monitoring of patients with CAPS, TRAPS, MKD and DIRA, and to standardise and improve care, quality of life and disease outcomes.

The 2021 EULAR/American College of Rheumatology points to consider for diagnosis, management and monitoring of the interleukin-1 mediated autoinflammatory diseases: cryopyrin-associated periodic syndromes, tumour necrosis factor receptor-associated periodic syndrome, mevalonate kinase deficiency, and deficiency of the interleukin-1 receptor antagonist

BACKGROUND

The interleukin-1 (IL-1) mediated systemic autoinflammatory diseases, including the cryopyrin-associated periodic syndromes (CAPS), tumour necrosis factor receptor-associated periodic syndrome (TRAPS), mevalonate kinase deficiency (MKD) and deficiency of the IL-1 receptor antagonist (DIRA), belong to a group of rare immunodysregulatory diseases that primarily present in early childhood with variable multiorgan involvement. When untreated, patients with severe clinical phenotypes have a poor prognosis, and diagnosis and management of these patients can be challenging. However, approved treatments targeting the proinflammatory cytokine IL-1 have been life changing and have significantly improved patient outcomes.

OBJECTIVE

To establish evidence-based recommendations for diagnosis, treatment and monitoring of patients with IL-1 mediated autoinflammatory diseases to standardise their management.

METHODS

A multinational, multidisciplinary task force consisting of physician experts, including rheumatologists, patients or caregivers and allied healthcare professionals, was established. Evidence synthesis, including systematic literature review and expert consensus (Delphi) via surveys, was conducted. Consensus methodology was used to formulate and vote on statements to guide optimal patient care.

RESULTS

The task force devised five overarching principles, 14 statements related to diagnosis, 10 on therapy, and nine focused on long-term monitoring that were evidence and/or consensus-based for patients with IL-1 mediated diseases. An outline was developed for disease-specific monitoring of inflammation-induced organ damage progression and reported treatments of CAPS, TRAPS, MKD and DIRA.

CONCLUSION

The 2021 EULAR/American College of Rheumatology points to consider represent state-of-the-art knowledge based on published data and expert opinion to guide diagnostic evaluation, treatment and monitoring of patients with CAPS, TRAPS, MKD and DIRA, and to standardise and improve care, quality of life and disease outcomes.

Mevalonate Kinase-Associated Diseases: Hunting for Phenotype-Genotype Correlation

Mevalonate kinase-associated diseases (MKAD) are caused by pathogenic mutations in the mevalonate kinase gene (MVK) and encompass several phenotypically different rare and hereditary autoinflammatory conditions. The most serious is a recessive systemic metabolic disease called mevalonic aciduria, and the most recently recognized is disseminated superficial actinic porokeratosis, a dominant disease limited to the skin. To evaluate a possible correlation between genotypes and (1) the different MKAD clinical subtypes or (2) the occurrence of severe manifestations, data were reviewed for all patients with MVK variants described in the literature (N = 346), as well as those referred to our center (N = 51). The genotypes including p.(Val377Ile) (homozygous or compound heterozygous) were more frequent in mild systemic forms but were also sometimes encountered with severe disease. We confirmed that amyloidosis was more prevalent in patients compound heterozygous for p.(Ile268Thr) and p.(Val377Ile) than in others and revealed new associations. Patients homozygous for p.(Leu264Phe), p.(Ala334Thr) or compound heterozygous for p.(His20Pro) and p.(Ala334Thr) had increased risk of severe neurological or ocular symptoms. All patients homozygous for p.(Leu264Phe) had a cataract. The variants associated with porokeratosis were relatively specific and more frequently caused a frameshift than in patients with other clinical forms (26% vs. 6%). We provide practical recommendations focusing on phenotype-genotype correlation in MKAD that could be helpful for prophylactic management.

Monogenic autoinflammatory disorders: beyond the periodic fever

The past two decades have seen an exponential increase in the number of monogenic autoinflammatory disorders described, coinciding with improved genetic sequencing techniques. This group of disorders has evolved to be heterogeneous and certainly more complex than the original four 'periodic fever syndromes' caused by innate immune over-activation. This review aims to provide an update on the classic periodic fever syndromes as well as introducing the broadening spectrum of clinical features seen in more recently described conditions.

Directed evolution of mevalonate kinase in Escherichia coli by random mutagenesis for improved lycopene

Lycopene is a terpenoid pigment that has diverse applications in the fields of food and medicine.

Hyperimmunoglobulinaemia D syndrome: a rare cause of prolonged fever and treatment with anti-interleukin 1 agent

Hyperimmunoglobulinaemia D syndrome (HIDS) is an autosomal recessive, autoinflammatory disease that is characterised with intermittent febrile episodes, cervical lymphadenopathy, rashes, arthritis and gastrointestinal symptoms associated with synovial or serosal inflammation. HIDS is caused by mutations in the gene encoding mevalonate kinase enzyme. The febrile attacks usually start in early childhood and triggered by stress or vaccinations. We report a case of 16-month-old boy who had episodes of recurrent fever accompanied by maculopapular rash and lymphadenopathy. He was diagnosed as HIDS and he had heterozygote mutation of mevalonate kinase gene.

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.

An update on autoinflammatory diseases

Autoinflammatory diseases area group of clinical conditions other than autoimmune diseases, characterized by recurrent inflammatory episodes. From apathogenetic point of view they are determined by a dys regulation of innate immunity, without involvement of specific immunity (auto reactive T cells and auto antibodies). Recently, the increased knowledge in the field of auto inflammation highlighted shared immune mechanisms in the pathogenesis of both classical monogenetic and multifactorial auto inflammatory diseases and a broad spectrum of chronic age-related inflammatory pathologies. The current increase in the prevalence of chronic inflammatory diseases makes this subject of topical interest. In the light of these considerations, we propose an update of auto inflammatory diseases and a new interpretation of auto inflammation with both theoretical and clinical implications.

Autoinflammatory syndromes for the dermatologist

While autoimmunity as cause of disease is well-established, other categories of immune-mediated diseases that are not produced by targeting of self-antigens by antibodies is in the process of being described. These so-called autoinflammatory diseases arise when an inappropriate activation of antigen-independent mechanisms occurs. Autoinflammatory diseases course with recurrent attacks of fever and multisystemic inflammation; however, the skin may also be affected by a variety of inflammatory manifestations that often alert the clinician about the presence of an autoinflammatory disease. Recognizing the cutaneous features of these syndromes will aid for prompt diagnosis and early treatment that is key for the quality of life and survival of the affected patients. In this paper, we focus on the skin manifestations of autoinflammatory diseases in children, which is the usual period of appearing of the first symptoms and signs.

Mevalonate kinase gene mutations and their clinical correlations in Behçet's disease

AIM

Genetics is suggested to play a role in the development of Behçet's disease (BD). Shared phenotipic features requires an approach to differential diagnosis from periodic febrile syndromes. We planned to study for mevalonate kinase (MVK) as a candidate for a susceptibility gene for Behçet's disease.

METHOD

Consecutive Behçet patients and apperently healthy subjects were included. Severity score of Behçet disease was calculated. Genotyping of mevalonate kinase gene was performed by polymerase chain reaction/sequence-based typing technique.

RESULTS

Fifty BD patients (median age: 38.30 ± 11.06 years) and 51 controls (median age: 33.88 ± 12.47 years) were recruited. Three types of mutations have been found: first, a single nucleotide polymorphism (SNP) c.769-38C>T (rs35191208) in 21 of 50 BD patients and in 15 of 51 controls. Both groups were comparable for the frequency of c.769-38C>T (P > 0.05). In all of the cases with c.769-38C>T, a second SNP, c885+24G>A (rs2270374) was also present (previously reported to be in linkage disequilibrium with the first SNP). A third SNP, c.769-7T>G (rs104895331) was found in three of 50 BD patients and in one of the control group. We found this SNP together with c769-38C>T and c.885+24G>A. The neurological involvement was found to be more frequent in the BD patients with c.769-3C>T when compared to the BD patients without this polymorphism (P = 0.012).

CONCLUSION

Our results suggested that the effects of MVK mutations in Behçet's disease could be an additional genetic susceptibility factor for the patients with neurological involvement. However, these results need confirmation in larger study populations and in different ethnic groups.

A taste of periodic fever syndromes

Periodic fevers are acquired or inherited disorders of innate immunity, which were first described in the 1940s. The patients are typically young at onset and have regularly recurring fevers for a few days to a few weeks with systemic inflammatory symptoms that are interrupted by symptom-free periods. There is a variety of clinical manifestations including gastrointestinal complaints, myalgias, arthralgias, and rash. A differential diagnosis in these patients may include recurrent infections, other inflammatory disorders, and neoplastic disease. This clinical review focuses on a sample of autoinflammatory disorders including familial Mediterranean fever, tumor necrosis factor receptor 1-associated periodic syndrome, hyperimmunoglobulinemia D syndrome, the cryopyrin-associated periodic syndrome, and periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis syndrome. We review the basics, pertinent clinical and laboratory features, and management of each entity.

Unexplained recurrent fever: when is autoinflammation the explanation?

Recurrent fever can be the sole or leading manifestation of a variety of diseases including malignancies, autoimmune diseases and infections. Because the differential diagnoses are manifold, no formal guidelines for the approach of patients with recurrent fever exists. The newly recognized group of autoinflammatory diseases are often accompanied by repetitive fever attacks. As these episodes are frequently associated by a variety of divergent presentations, the differentiation of other causes for febrile illnesses can be difficult. In this article, we first review disease entities, which frequently present with the symptom of recurrent fever. In a next step, we summarize their characteristic pattern of disease presentation. Finally, we analyse key features of autoinflammatory diseases, which are helpful to distinguish this group of diseases from the other causes of recurrent fever. Recognizing these symptom patterns can provide the crucial clues and, thus, lead to the initiation of targeted specific diagnostic tests and therapies.

Mevalonate kinase genotype in children with recurrent fevers and high serum IgD level

In selected cases, childhood's recurrent fevers of unknown origin can be referred to systemic autoinflammatory diseases as mevalonate kinase deficiency (MKD), caused by mutations in the mevalonate kinase gene (MVK), previously named "hyper-IgD syndrome" due to its characteristic increase in serum IgD level. There is no clear evidence for studying MVK genotype in these patients. From a cohort of 305 children evaluated for recurrent fevers in our outpatient clinic during the decade 2001-2011, we have retrospectively selected 10 unrelated Italian children displaying febrile episodes, associated with recurrent inflammatory signs (variably involving gastrointestinal tube, joints, lymph nodes, and skin) and persistently increased serum IgD levels. All these patients were examined for MVK genotype: only 2 presented bonafide MVK mutations, 5 showed the same S52N MVK polymorphism, while the remaining 3 had a wild-type MVK sequence. Clinical details of these patients have been reviewed through the critical analysis of their medical charts. Our report underscores the pitfalls of MKD diagnosis based on clinical grounds and IgD levels, emphasizing the uncertain contribution of MVK polymorphisms in the diagnostic assessment of the syndrome.

Clinical and biochemical landmarks in systemic autoinflammatory diseases

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

Establishment of a transgenic mouse model with liver-specific expression of secretory immunoglobulin D

Mutation of mevalonate kinase (MVK) is thought to account for most cases of hyperimmunoglobulinemia D syndrome (HIDS) with recurrent fever. However, its mechanism and the relationship between elevated serum immunoglobulin D (IgD) and the clinical features of HIDS are unclear. In this study, we generated by fusion PCR a vector to express high levels of chimeric secretory IgD (csIgD) specifically in the liver. We then generated seven founder lines of transgenic mice by co-microinjection, and verified them using genomic PCR and Southern blotting. We detected the expression of csIgD by reverse transcription PCR, quantitative PCR, western blotting, and enzyme-linked immunosorbent assays. We demonstrated that csIgD could be specifically and stably expressed in the liver. We used flow cytometry to show that overexpression of csIgD in the bone marrow and spleen cells had no effect on B cell development. Morphologic and anatomical observation of the transgenic mice revealed skin damage, hepatosplenomegaly, and nephromegaly in some transgenic mice; in these mice, pathological sections showed high levels of cell necrosis and protein-like sediments in the liver, spleen, and kidney. We demonstrated that the genomic insertion sites of the transgenes did not disrupt the MVK gene on mouse chromosome 5. This transgenic mouse will be useful to explore the pathogenesis of HIDS.

A novel mutation of IL1RN in the deficiency of interleukin-1 receptor antagonist syndrome: description of two unrelated cases from Brazil

OBJECTIVE

Monogenic autoinflammatory diseases are disorders of Mendelian inheritance that are characterized by mutations in genes that regulate innate immunity and whose typical features are systemic inflammation without high-titer autoantibodies or antigen-specific T cells. Skin and bone inflammation in the newborn period have been described in 3 of these autoinflammatory disorders: neonatal-onset multisystem inflammatory disease, Majeed syndrome, and deficiency of interleukin-1 (IL-1) receptor antagonist (DIRA) syndrome. This study was undertaken to present the characteristics of the DIRA syndrome in 2 cases from Brazil, and describe a novel mutation in IL1RN.

METHODS

Two unrelated Brazilian patients were evaluated for the clinical signs and symptoms of these 3 disorders, and peripheral blood samples were assessed for mutations in NLRP3, LPIN2, and IL1RN by DNA resequencing analysis. A mutation in IL1RN that encodes a mutant protein was identified, and the expression and function of this mutant protein were compared to those of the wild-type protein.

RESULTS

Both patients presented with pustular dermatitis resembling generalized pustular psoriasis, recurrent multifocal aseptic osteomyelitis, and elevation in the levels of acute-phase reactants, all of which are features most consistent with the DIRA syndrome. Chronic lung disease was observed in 1 of the patients, and jugular venous thrombosis was observed in the other patient. Both patients showed a partial response to corticosteroid therapy, and 1 patient experienced an initial improvement of dermatitis with the use of acitretin. Both patients were homozygous for a novel 15-bp (in-frame) deletion on the IL1RN gene. The mutated protein expressed in vitro had no affinity with the IL-1 receptor, and stimulation of the patients' cells with recombinant human IL-1α or IL-1β led to oversecretion of proinflammatory cytokines, similar to the findings obtained in previously reported patients.

CONCLUSION

The presence of the same homozygous novel mutation in IL1RN in 2 unrelated Brazilian patients suggests that this genetic variant may be a founder mutation that has been introduced in the Brazilian population.

Different clinical presentation of the hyperimmunoglobulin D syndrome (HIDS) (four cases from Turkey)

Hyperimmunoglobulin D syndrome (HIDS) is one of the autoinflammatory syndromes which are characterized by febrile attacks. Duration and frequency of the febrile attacks, as well as typical organ involvements vary greatly. Recently, it is possible to reach more reliable data by the possibilities that are opened up by molecular genetics in order to highlight the aetiopathogenesis of this group of diseases. Typical patients with HIDS have an onset of disease in the first year of life. Here, we report four Turkish HIDS cases; three of whom, the symptoms started at a later age. The diagnoses were made by relevant clinical symptoms along with MVK mutations detected by DNA sequencing method. As summarised in this article, HIDS could be presented with a broad spectrum of symptoms. Although most of the HIDS patients are reported from Europe and especially Dutch ancestry, case reports are presented from all over the world. For this reason, HIDS should be kept in mind for the differential diagnosis of periodic fever syndromes or before accepting an FMF patient as colchichine resistant. We suppose that the phenomenon of "later-onset HIDS" should shed light into unresolved clinical problems of patients with periodic fever. Especially in countries that FMF is more frequent such as Turkey, even though the symptoms start later than classic cases, HIDS should be kept in mind for differential diagnosis of periodic fever syndromes.

The emerging role of interleukin-1β in autoinflammatory diseases

The autoinflammatory syndromes are a group of multisystem disorders characterized by recurrent episodes of fever and systemic inflammation affecting the eyes, joints, skin, and serosal surfaces in the absence of an immune reaction. Recent advances have revealed the importance of interleukin-1β, not only in the pathogenesis of many of these rare inherited diseases, but also in acquired diseases. The development and availability of anti-interleukin-1β therapeutics have introduced the possibility of proof-of-concept studies, which are likely to further widen this field.

Autoinflammatory syndromes: diagnosis and management

During the last decades the description of autoinflammatory syndromes induced great interest among the scientific community. Mainly rheumatologists, immunologists and pediatricians are involved in the discovery of etiopathogenesis of these syndromes and in the recognition of affected patients. In this paper we will discuss the most important clues of monogenic and non-genetic inflammatory syndromes to help pediatricians in the diagnosis and treatment of these diseases.

A Clinical Criterion to Exclude the Hyperimmunoglobulin D Syndrome (Mild Mevalonate Kinase Deficiency) in Patients with Recurrent Fever

Objective.

The hyperimmunoglobulin D syndrome (HIDS) is an autosomal recessive autoinflammatory disease caused by mutations in the mevalonate kinase gene. Our objective was to define a clinical criterion able to exclude HIDS without the need of genetic testing.

Methods.

A recursive partitioning algorithm was applied to derive the clinical criterion in 149 patients with genetic testing in a French laboratory, among whom 35 had HIDS. The criterion was validated in 93 patients with genetic testing in a Dutch laboratory, among whom 28 had HIDS.

Results.

The most discriminatory composite clinical criterion satisfied by all patients with HIDS in the derivation group was [onset age < 5 years old OR (joint pain during attacks AND length of attacks < 14 days)]. It had a sensitivity of 100% (95% confidence interval 88% to 100%) and a specificity of 28% (95% CI 17% to 40%) in the validation group. If genetic testing had been limited to patients fulfilling this criterion, 18 tests (19%) would have been avoided in this highly selected validation sample, without missing a single patient with HIDS.

Conclusion.

Even among patients already selected by expert physicians, this criterion could help prevent unnecessary genetic testing, which is resource- and time-consuming.

Dysregulation of innate immunity: hereditary periodic fever syndromes

The hereditary periodic fever syndromes encompass a rare group of diseases that have lifelong recurrent episodes of inflammatory symptoms and an acute phase response in common. Clinical presentation can mimic that of lymphoproliferative disorders and patients often go undiagnosed for many years. These syndromes follow an autosomal inheritance pattern, and the major syndromes are linked to specific genes, most of which are involved in regulation of the innate immune response through pathways of apoptosis, nuclear factor kappaBeta activation and cytokine production. In others, the link between the protein involved and inflammation is less clear. The recurrent inflammation can lead to complications, such as renal impairment due to amyloidosis and vasculitis, visual impairment, hearing loss, and joint destruction, depending on the specific syndrome. In recent years, treatment options for these diseases have improved significantly. Early establishment of an accurate diagnosis and start of appropriate therapy improves prognosis in these patients.

Mutations in NALP12 cause hereditary periodic fever syndromes

NALP proteins, also known as NLRPs, belong to the CATERPILLER protein family involved, like Toll-like receptors, in the recognition of microbial molecules and the subsequent activation of inflammatory and immune responses. Current advances in the function of NALPs support the recently proposed model of a disease continuum bridging autoimmune and autoinflammatory disorders. Among these diseases, hereditary periodic fevers (HPFs) are Mendelian disorders associated with sequence variations in very few genes; these variations are mostly missense mutations whose deleterious effect, which is particularly difficult to assess, is often questionable. The growing number of identified sporadic cases of periodic fever syndrome, together with the lack of discriminatory clinical criteria, has greatly hampered the identification of new disease-causing genes, a step that is, however, essential for appropriate management of these disorders. Using a candidate gene approach, we identified nonambiguous mutations in NALP12 (i.e., nonsense and splice site) in two families with periodic fever syndromes. As shown by means of functional studies, these two NALP12 mutations have a deleterious effect on NF-kappaB signaling. Overall, these data identify a group of HPFs defined by molecular defects in NALP12, opening up new ways to manage these disorders. The identification of these first NALP12 mutations in patients with autoinflammatory disorder also clearly demonstrates the crucial role of NALP12 in inflammatory signaling pathways, thereby assigning a precise function to this particular member of an emerging family of proteins whose putative biological properties are currently inferred essentially through in vitro means.

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.

Diagnostics and therapeutic insights in a severe case of mevalonate kinase deficiency

Mevalonate kinase deficiency is a rare inborn disorder of isoprenoid and sterol biosynthesis characterized by a recurrent autoinflammatory syndrome and, in most severe cases, psychomotor delay. Clinical manifestations can be very complex and, in some cases, mimic a chronic inflammatory disease. Diagnosis is also complex and often requires immunologic, genetic, and biochemical investigations. There is no standardized therapy, but biological agents could help to control inflammatory complaints in some cases. A severe case of mevalonate kinase deficiency that was associated with nephritis and successfully treated with anakinra (interleukin 1 receptor antagonist) is reported here, and new insights into diagnosis and therapy of this complex disorder are discussed.

Autoinflammatory gene mutations in Behçet's disease

BACKGROUND

Behçet's disease (BD) shares clinical features with well-recognised autoinflammatory disorders. In addition, mutations in genes for familial Mediterranean fever and tumour necrosis factor receptor-associated periodic syndrome have been reported to have increased in patients with BD.

PATIENTS AND METHODS

DNA samples from 97 patients with BD and 51 matched healthy controls were analysed for the mevalonate kinase (MVK), cold-induced autoinflammatory syndrome 1 (CIAS1) and proline/serine/threonine phosphatase-interacting protein 1 (PSTPIP1) genes, responsible for mevalonate kinase deficiency (MKD), cryopyrin associated periodic syndromes (CAPS) and pyogenic sterile arthritis, pyoderma gangrenosum and acne (PAPA) syndrome, respectively. Over 90% of known mutations were screened using restriction fragment length polymorphism analysis and/or sequencing.

RESULTS

Two patients had paired mutations in the MVK gene (genotypes V377I/V377I and V377I/S135L) and displayed typical features of BD and MKD. Another was heterozygotic for the V377I genotype. The V198M mutation in the CIAS1 gene was identified in one patient with typical BD but no symptoms of CAPS. No mutations were identified in the control group. PSTPIP1 analysis revealed a new exon 10 insertion variant (c.741+33_741+34insGT) in 2 of 97 patients and in 1 of 51 controls (p>0.05), indicating that it is a polymorphism rather than a true mutation.

DISCUSSION

This study could not demonstrate any significant increases in MVK, CIAS1 or PSTPIP1 mutations in patients with BD as compared with controls.

[Auto-inflammatory disease with hyperimmunoglobulinemia D of late onset]

BACKGROUND

The term "auto-inflammatory diseases" encompasses a group of disorders characterised by febrile episodes of sudden onset associated with joint, abdominal, lymph node and cutaneous signs, each presenting a genetic and/or laboratory specificity allowing their identification. Polyclonal elevation of serum IgD is highly suggestive of hyper-IgD syndrome, a disease with autosomal recessive transmission that usually begins before the age of one year.

CASE REPORT

We report the case of a 46-year-old woman presenting a disease since the age of 30 years clinically very similar to hyper-IgD syndrome except for ocular and pulmonary involvement. However, tests revealed neither mevalonate kinase gene mutation nor elevation of urinary mevalonic acid. The near-monthly attacks were controlled with mycophenolate mofetil.

DISCUSSION

Three cases with identical clinical and laboratory profiles have been reported in the literature and diagnosed as late-onset hyper-IgD syndrome. Our case is the only one involving indirect screening for mutation of the mevalonate kinase gene, which proved negative. This finding rules out the diagnosis of classic hyper-IgD syndrome in our case and raises the possibility of auto-inflammatory disease with reactional hyper-IgD of a different cause, either acquired or secondary to an as yet unidentified mutation.

Diagnostic challenge of hyper-IgD syndrome in four children with inflammatory gastrointestinal complaints

OBJECTIVE

Hyper-IgD syndrome (HIDS) is a rare autosomal recessive disease characterized by recurrent fever, lymphadenopathy, diarrhoea, abdominal pain, headache, arthralgia and skin rash. Abdominal symptomatology may mimic inflammatory bowel disease. We report on four patients with HIDS who had been previously investigated for Crohn's disease (CD). The levels of IgD were measured in a series of patients with CD to evaluate the specificity of this assay in the differential diagnosis between the two conditions.

MATERIAL AND METHODS

Diagnosis of HIDS was based on clinical criteria as well as immunological or genetic data. IgD levels were measured in the four subjects affected by HIDS, in 59 patients with CD and in a group of 160 healthy controls.

RESULT

All patients underwent a variety of gastroenterological investigations because inflammatory bowel disease was suspected. Ultrasonography was pathologic in all the patients, showing enlargement of mesenteric lymph nodes. Abdominal leucocyte scintigraphy displayed diffuse signals of mild to moderate degree. IgD and IgA levels were elevated in three out of four patients. No difference in IgD values was found in CD patients as compared to the control group.

CONCLUSIONS

Gastrointestinal complaints associated with recurrent fever and mesenteric adenopathy warrant genetic investigation for HIDS, in order to avoid unnecessary invasive investigations and treatment.

Approach to genetic analysis in the diagnosis of hereditary autoinflammatory syndromes

OBJECTIVE

Hereditary autoinflammatory syndromes are characterized by recurrent episodes of fever and inflammation. Seven subtypes have been described, caused by mutations in four different genes. Apart from a common phenotype of lifelong recurrent inflammatory attacks, all subtypes have distinct features and specific therapeutic options, which emphasizes the need for a specific diagnosis in each case. Our aim was to examine whether genetic screening would allow classification of previously unclassified patients, and whether individual patients suffering from an autoinflammatory syndrome carry additional mutations in one of the other autoinflammatory genes.

METHODS

We included 60 patients with an unclassified autoinflammatory syndrome, 87 patients diagnosed with either hyper-IgD syndrome, familial Mediterranean fever (FMF) or tumour necrosis factor (TNF)-receptor-associated periodic syndrome and 50 healthy controls. Deoxyribonucleic acid samples were screened for the most prevalent mutations in the MEFV, TNFRSF1A, MVK and CIAS1 genes.

RESULTS

We found only one possible diagnosis of FMF in the 60 previously unclassified patients. Two low-penetrance mutations were found in equal numbers in the groups of patients and controls.

CONCLUSIONS

Screening of highly prevalent mutations in known genes involved in these disorders does not yield additional relevant information. Differential diagnosis of hereditary autoinflammatory syndromes can be made by thorough clinical examination followed by targeted genetic analysis of the one or two most likely syndromes. High-prevalence low-penetrant mutations from autoinflammatory genes do not occur more frequently in patients with hereditary autoinflammatory syndromes compared with the general population.

Tendonitis in variant hyperimmunoglobulinaemia D and periodic fever syndrome--a rare disease with a new symptom

Hyperimmunoglobulinaemia D syndrome (HIDS) is defined as recurrent fever, generalised lymphadenitis, abdominal pain, arthritis and raised polyclonal serum IgD >100 IU/ml. The cause is a mutation in the mevalonate kinase gene. Other periodic fever syndromes are known. We report a new patient and describe orbital tendonitis as a hitherto unreported symptom

CONCLUSION

Without any underlying cause, the tendonitis must be seen as new symptom of variant hyperimmunoglobulinaemia D syndrome. We speculate that the inflammation of the Tenon spatium is similar to the process of inflammation of the connective tissue in the joint in hyperimmunoglobulinaemia D syndrome where deposits of C3 and IgM are present. Variant hyperimmunoglobulinaemia D syndrome can be present in one family.

Periodic fever in children with hyperimmunoglobulinemia D and mevalonate kinase mutations

Hyperimmunoglobulinemia D syndrome (HIDS) is one cause of periodic fevers in children. HIDS is associated with mutations in the mevalonate kinases gene on chromosome 12. Most cases of HIDS have been reported from the Netherlands and surrounding European countries. It is likely that HIDS is underdiagnosed in the United States.

Henoch-Schönlein purpura in a child with hyperimmunoglobulinemia D and periodic fever syndrome

This report describes a 3-year-old girl with a long history of periodic fever who presented with Henoch-Schönlein purpura. She was diagnosed with hyperimmunoglobulinemia D and periodic fever syndrome by means of mutation analysis of the mevalonate kinase gene. The serum IgA concentration was markedly elevated, but the serum IgD concentration was normal. This report emphasizes that Henoch-Schönlein purpura may be an important clinical feature of hyperimmunoglobulinemia D and periodic fever syndrome. In addition, this syndrome should be considered in patients with Henoch-Schonlein purpura in whom there is a history of recurrent fevers, even when the serum IgD concentration is normal.

Pseudodominant inheritance of the hyperimmunoglobulinemia D with periodic fever syndrome in a mother and her two monozygotic twins

Hyperimmunoglobulinemia D with periodic fever syndrome (HIDS) is a recessively inherited recurrent fever syndrome. We describe a family of 2 monozygotic twins and their mother with characteristic symptoms of HIDS, but normal levels of IgD and IgA, and with a dominant inheritance pattern. Mevalonate kinase (MK) activity was deficient in both children, and analysis of the MVK gene revealed compound heterozygosity for 2 new mutations, G25G and R277H. Being positioned adjacent to a donor splice site, the G25G mutation was shown by reverse transcription-polymerase chain reaction analyses to cause aberrant splicing of the MVK messenger RNA, thus being disease-relevant. The mother, who was also symptomatic during her childhood and adolescence, was a compound heterozygote for I268T and R277H. Our findings expand the genetic and ethnic spectrum of HIDS and show that the possible presence of this disease cannot be excluded based solely on inheritance patterns. In each case in which HIDS is clinically suspected, analysis of MK activity and/or the MVK gene (especially exons 9 and 11) should be performed.

Tumor necrosis factor receptor-associated periodic syndrome (TRAPS): definition, semiology, prognosis, pathogenesis, treatment, and place relative to other periodic joint diseases

Tumor necrosis factor receptor-associated periodic syndrome (TRAPS) is an autosomal dominant inherited condition of periodic fever and pain. Most patients are of northern European descent. The attacks manifest as fever and pain in the joints, abdomen, muscles, skin, or eyes, with variations across patients. An acute-phase response occurs during the attacks. Patients with TRAPS are at risk for AA amyloidosis, the most common targets being the kidneys and liver. Soluble TNFRSF1A is usually low between the attacks and may be normal during the attacks, when TNF levels are high. TNFRSF1A is found in abnormally high numbers on leukocyte cell membranes. TRAPS is the first condition for which naturally occurring mutations in a TNF receptor were found; the mutations affect the soluble TNFRSF1A gene in the 12p13 region. In some patients, the pathogenesis involves defective TNFRSF1A shedding from cell membranes in response to a given stimulus. Thus, TRAPS is a model for a novel pathogenic concept characterized by failure to shed a cytokine receptor. This review compares TRAPS to other inherited periodic febrile conditions, namely, familial Mediterranean fever, Muckle-Wells syndrome, cold urticaria, and hyper-IgD syndrome. The place of TRAPS relative to other intermittent systemic joint diseases is discussed. Colchicine neither relieves nor prevents the attacks, whereas oral glucocorticoid therapy is effective when used in dosages greater than 20 mg/day. The pathogenic hypothesis involving defective TNFRSF1A shedding suggests that medications targeting TNF may be effective in TRAPS.

Effect of inflammatory attacks in the classical type hyper-IgD syndrome on immunoglobulin D, cholesterol and parameters of the acute phase response

BACKGROUND

Classical type hyper-immunoglobulin D (IgD) syndrome (HIDS) is an hereditary auto-inflammatory disorder, characterized by recurrent episodes of fever, lymphadenopathy, abdominal distress and a high serum concentration of IgD. It is caused by mevalonate kinase deficiency.

OBJECTIVE

To further characterize the acute phase response during fever attacks in HIDS in order to improve diagnosis.

SUBJECTS

Twenty-two mevalonate kinase-deficient HIDS patients.

METHODS

Blood samples were drawn during and in between febrile attacks, and concentrations ofC-reactive protein (CRP), ferritin, procalcitonin, pentraxin 3, IgD and cholesterol in several lipoprotein fractions were determined.

RESULTS

The marked acute phase response at the time of a fever attack in classical type HIDS is reflected by a rise in CRP accompanied by a moderate but statistically significant rise in procalcitonin and pentraxin 3. In only two of 22 patients, procalcitonin concentration rose above 2 ng mL(-1) during fever attack, compatible with the noninfectious nature of these attacks. Ferritin does not reach the high concentrations found in adult-onset Still's disease. Despite the defect in mevalonate kinase, a component of cholesterol metabolism, serum cholesterol did not change during attacks. IgD concentration is elevated regardless of disease activity, although there is appreciable variation during life. Its role in HIDS remains unclear.

CONCLUSION

The combination of high CRP concentration plus procalcitonin concentration <2 ng mL(-1) in a symptomatic HIDS patient might indicate a febrile attack without (bacterial) infection; this observation warrants further investigation for its usefulness as a marker in clinical practice.

Hyperimmunoglobulinemia D syndrome in an Arab child

Hyperimmunoglobulinemia D syndrome (HIDS) is newly recognized and resembles familial Mediterranean fever (FMF). It is inherited as an autosomal recessive trait. Mutation of the gene coding for mevalonate kinase is responsible for the disease. The gene is located at chromosome 12q24. The patients initially described were of Dutch ancestry. Other cases from Turkey and Armenia were reported. The case we present is the first from Arab countries to be registered in the International HIDS Registry and to our knowledge the first to be reported.

Molecular analysis of the MVK and TNFRSF1A genes in patients with a clinical presentation typical of the hyperimmunoglobulinemia D with periodic fever syndrome: A low-penetrance TNFRSF1A variant in a heterozygous MVK carrier possibly influences the phenot

OBJECTIVE

To describe biochemical findings and the spectrum of mevalonate kinase (MVK) gene mutations as well as an associated TNFRSF1A low-penetrance variant in a series of patients with clinical features of the hyperimmunoglobulinemia D with periodic fever syndrome (HIDS).

METHODS

The MVK gene was sequenced in 8 children and 1 adult (including 2 siblings) fulfilling the clinical criteria for HIDS. In addition, sequencing of exons 2, 3, 4, and 6 of the TNFRSF1A gene was performed in patients with only one or no MVK mutation. Mevalonate kinase (MK) enzyme activity in leukocytes and renal excretion of mevalonic acid were also measured.

RESULTS

Mutations in the coding region of the MVK gene were detected in 6 patients, and the most common mutation was V377I. Among these patients were 2 novel mutations, both of which were located in exon 6. These novel mutations resulted in the substitution of tryptophan (TGG) by a stop codon (TGA) at amino acid position 188 (W188X) and in the exchange of valine (GTG) for alanine (GCG) at amino acid position 203 (V203A). In 1 patient, a combination of one MVK (V377I) mutation and one TNFRSF1A (R92Q) mutation was present. The patient's clinical phenotype resembled a mixture of variant-type HIDS and tumor necrosis factor receptor-associated periodic syndrome (TRAPS). Her IgD values varied between normal and slightly increased, and the MK activity was in the low-normal range, while urinary mevalonate concentrations were always normal.

CONCLUSION

The genotype findings indicate that a relatively small number of genes may be involved in the clinical manifestation of HIDS, with low-penetrance TNFRSF1A variants possibly influencing the HIDS phenotype or MVK mutations contributing to TRAPS.

A patient with hyper-IgD syndrome in Antalya, Turkey

Hyper-IgD syndrome is a periodic fever syndrome that presents with recurrent episodes of high fever accompanied by lymphadenopathy, abdominal distress, arthralgias or arthritis, headache and skin lesions. The diagnosis is based on clinical grounds and elevated serum IgD levels (>100 U/ml), but requires a high index of suspicion, and a mevalonate kinase enzyme defect. Most patients are from western Europe but there are others identified in other countries. We describe a 17-year-old patient who had been followed with the diagnosis of familial Mediterranean fever for a long time before she was diagnosed with hyper-IgD syndrome.