Canakinumab treatment real world evidence in 3 monogenic periodic fever syndromes in 2009-2022: an interim analysis using the French JIR cohort database.

BACKGROUND: Our study aimed to provide real-world evidence on the treatment patterns, effectiveness and safety of canakinumab in France in Familial Mediterranean Fever (FMF), Mevalonate Kinase Deficiency (MKD), and Tumor necrosis factor Receptor Associated Periodic Syndrome (TRAPS). METHODS: This study used the JIR cohort, a multicentre international registry created in 2013 to collect data on patients with juvenile inflammatory rheumatic diseases. French patients diagnosed with FMF, MKD or TRAPS and treated with canakinumab were included in this study. RESULTS: 31 FMF, 26 MKD and 7 TRAPS patients received canakinumab during the study period. Most of them initiated canakinumab at the recommended dose of 2 mg/kg or 150 mg, but less than half of FMF and MKD patients initiated it at the recommended frequency (every 4 weeks). Two years after initiation, the rate of patients still on treatment was 78.1% in FMF, 73.7% in MKD, and 85.7% in TRAPS patients. While the dose per injection remained globally the same over the course of the treatment, some adjustments of the dose intervals were observed. Six patients had a severe adverse event reported. Of those, three were possibly related to canakinumab. CONCLUSION: This interim analysis showed a good maintenance of canakinumab treatment 2 years after initiation and confirmed its safety profile in real-life practice in France in patients diagnosed with FMF, MKD and TRAPS. The high variety of dose and interval combinations observed in canakinumab treated patients let suppose that physicians adapt the posology to individual situations rather than a fixed treatment plan.

Practical Approach to Diagnosis and Management of IL-1-Mediated Autoinflammatory Diseases (CAPS, TRAPS, MKD, and DIRA).

Systemic autoinflammatory diseases (SAIDs) are a group of rare genetic and nongenetic immune dysregulatory disorders associated with high morbidity and mortality if left untreated. Therefore, early diagnosis and initiation of targeted treatment is vital in SAID patients to control the disease activity and prevent long-term immune-mediated damage. A specific group of genetically defined SAIDs is associated with increased inflammasome-mediated production of active interleukin (IL)-1. Even though progress in immunobiology and genetics has brought forth diagnostic tools and novel treatments that have been described in the literature extensively, many challenges remain in the clinical setting. Some challenges that health care providers may face on a day-to-day basis include the requirement of a multidisciplinary approach due to the complexity of these diseases, limited evidence-based treatment options, and barriers to access available therapies. Primarily, IL-1 inhibitors anakinra, canakinumab, and rilonacept are used to control the inflammation in these patients, with the goal of achieving sustainable remission. Recently published provisional points to consider from the European Alliance of Associations for Rheumatology (EULAR) and American College of Rheumatology (ACR) provide diagnosis, management, and monitoring recommendations for four IL-1-mediated autoinflammatory diseases: 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). The goal of this paper is to aid health care professionals by providing a practical approach to diagnosis and management of these four IL-1 mediated SAIDs on the basis of the recent EULAR/ACR recommendations.

Long-term efficacy of canakinumab in hyperimmunoglobulin D syndrome.

Hyperimmunoglobulin D syndrome (HIDS) is a rare autoinflammatory disorder with autosomal recessive inheritance. It is caused by specific mutations in the mevalonate kinase gene (MVK). No treatment specific to HIDS has been approved to date; however, nonsteroidal anti-inflammatory drugs, steroids, colchicine, tumor necrosis factor-α inhibitors, and anti-interleukin-1 treatments are used, based on case reports and observational studies. Herein, we report a case with recurrent fever and arthritis attacks who did not respond to anakinra and was successfully treated with canakinumab. Long-term remission was achieved without any side effects with 300 mg canakinumab treatment every 4 weeks for 5 years.

A case of mevalonate kinase deficiency, neonatal Sweet syndrome, and inflammatory bowel disease.

Mevalonate kinase deficiency is a group of rare metabolic autoinflammatory disorders that present with recurrent fevers, abdominal pain, arthralgias, adenopathy, and a variety of cutaneous manifestations. The skin findings may mimic cellulitis, erythema elevatum diutinum, IgA vasculitis, and Sweet syndrome, and there is often a morbilliform or urticarial rash and aphthous stomatitis. Mevalonate kinase deficiency is one of the identified monogenic variants that can cause very early onset inflammatory bowel disease (IBD). We present a rare case of a patient with mevalonate kinase deficiency, neonatal Sweet syndrome, and infantile-onset IBD, who has been successfully treated with canakinumab therapy.

A case of neonatal sweet syndrome associated with mevalonate kinase deficiency.

BACKGROUND: Sweet syndrome (SS), also known as acute febrile neutrophilic dermatosis, is an immunologic syndrome characterized by widespread neutrophilic infiltration. Histiocytoid Sweet syndrome (H-SS) is a histopathologic variant of SS. While SS most commonly occurs in adults, this case report discusses an infant patient who presented with H-SS. CASE PRESENTATION: Through a multidisciplinary approach, this patient was also found to have very early onset inflammatory bowel disease (VEO-IBD) and Mevalonate kinase-associated disease (MKAD). While prior case studies have characterized an association between VEO-IBD and MKAD, there is no literature describing the association of all three diagnoses this case: H-SS, VEO-IBD and MKAD. Initiation of canakinumab in this patient resulted in successful control of the disease. CONCLUSIONS: This case highlights the importance of a multidisciplinary approach to rare diagnoses, and collaboration during cases with significant diagnostic uncertainty.

The assessment of autoinflammatory disease classification criteria (Eurofever/PRINTO) in a real-life cohort.

OBJECTIVE: The aim of the study was to determine the sensitivity and specificity rates of Eurofever/PRINTO autoinflammatory recurrent fever classification criteria with real-life data in patients with an autoinflammatory disease. METHODS: A total of 119 patients were included in the study. Based on clinical symptoms, they were divided into four subgroups: cryopyrin-associated periodic syndromes (CAPS), TNF receptor-associated periodic syndrome (TRAPS), mevalonate kinase deficiency (MKD), and syndrome of undifferentiated recurrent fever (SURF) using the Eurofever/PRINTO clinical classification criteria. In the last step, the patients were re-evaluated in the light of genetic results and their final diagnosis was reached. RESULTS: A total of 119 patients, including 37 CAPS, 13 TRAPS, 8 MKD, 39 SURF, 14 NLRP12-related autoinflammatory disease (NLRP12-AID), and 8 familial Mediterranean fever (FMF) patients were evaluated in the study. While the sensitivity of the new clinical Eurofever/PRINTO criteria was 48% for CAPS, 77% for TRAPS, 87.5%for MKD, and the specificity of the clinical criteria was 86% for CAPS, 85% for TRAPS, and 60% for MKD. The sensitivity of the new mixed (genetic plus clinical variables) Eurofever/PRINTO criteria was 27% for CAPS, 61% forTRAPS, 85% for MKD, and the specificity of the mixed criteria for each group was 100%. CONCLUSION: We found the sensitivity of the Eurofever/PRINTO classification criteria to be low as genotypic changes between populations cause phenotypic differences. For this reason, we think that patient-based evaluation is correct rather than standard classification criteria in real life. Key-points • In systemic autoinflammatory diseases, common variants in the populations may alter the phenotype, and making it difficult to classify some patients with the current classification criteria. • In populations with common genetic variants, the classification criteria should be modified according to the clinical phenotype.

A possibly new autoinflammatory disease due to compound heterozygous phosphomevalonate kinase gene mutation.

BACKGROUND: Mevalonate kinase (MVK) plays a role in cholesterol and non-sterol isoprenoid biosynthesis and its deficiency-related diseases are caused by bi-allelic pathogenic mutations in the MVK gene, (MVK), which leads to rare hereditary autoinflammatory diseases. The disease may manifest different clinical phenotypes depending on the degree of the deficiency in the enzyme activity. The complete deficiency of the enzyme activity results in the severe metabolic disease called mevalonic aciduria, while a partial deficiency results in a broad spectrum of clinical presentations called hyper-immunoglobulin D syndrome (HIDS). Serum immunoglobulin (Ig) D and urine mevalonic acid levels may be increased during inflammatory attacks of HIDS. CASE PRESENTATION: Herein, for the first time in the literature, we present a 6-year-old male patient who suffered from recurrent episodes of fever, polyarthritis, skin rash, diarrhea, abdominal pain, and inflammatory bowel disease-like manifestations with elevated levels of serum IgD, and urine mevalonic acid. Eventually we detected compound heterozygous mutations in the phosphomevalonate kinase (PMVK) gene coding the second enzyme after mevalonate kinase in the mevalonate pathway. CONCLUSION: For patients presenting with HIDS-like findings, disease exacerbations and persistent chronic inflammation, and having high urinary mevalonic acid and serum IgD levels, raising suspicion in terms of MVK deficiency (MVKD), it is recommended to study all mevalonate pathway enzymes, even if there is no mutation in the MVK gene. It should be kept in mind that novel mutations might be seen such as PMVK gene.

Diagnostic and therapeutic algorithms for monogenic autoinflammatory diseases presenting with recurrent fevers among adults.

Autoinflammatory diseases (AIDs) are defined as disorders of innate immunity. They were initially defined in contrast to autoimmune diseases because of the lack of involvement of the adaptive immune system and circulating autoantibodies. The four monogenic AIDs first described are called the 'historical' AIDs and include FMF (associated with MEFV mutations), cryopyrinopathies (associated with NLRP3 mutations), TNF receptor-associated periodic syndrome (associated with TNFRSF1A mutations) and mevalonate kinase deficiency (MKD; associated with MVK mutations). In the last 10 years, >50 new monogenic AIDs have been discovered due to genetic advances. The most important discovery for adult patients is VEXAS syndrome associated with somatic UBA1 mutations leading to an AID affecting mostly elderly men. Diagnosis of monogenic AIDs is based on personal and family history and detailed analysis of symptoms associated with febrile attacks in the context of elevated peripheral inflammatory markers. This review proposes a practical approach for the diagnosis of the main monogenic AIDs among adult patients.

Recurrent macrophage activation syndrome due to hyperimmunoglobulin D syndrome: a case-based review.

Hyperimmunoglobulin D syndrome (HIDS) is a hereditary autoinflammatory disease characterized by recurrent inflammatory attacks with fever, abdominal pain, lymphadenopathy, aphthous stomatitis, and skin lesions. There are few reports on HIDS patients complicated with macrophage activation syndrome (MAS); however, to our knowledge, there is no case of HIDS with recurrent MAS attacks. We report two pediatric patients initially diagnosed as Kawasaki disease and systemic juvenile idiopathic arthritis presented with recurrent MAS episodes with prolonged fever, skin rash, hepatosplenomegaly, cervical lymphadenopathy, aphthous stomatitis, headache, pancytopenia, hyperferritinemia, and hypofibrinogenemia, finally diagnosed as HIDS with a documented homozygous MVK gene mutation. This is the first report on recurrent MAS attacks due to HIDS in pediatric patients who were successful treated with corticosteroids and anti-IL-1 therapies. Thus, clinicians should be vigilantly investigated signs of autoinflammatory diseases in patients with recurrent MAS attacks during their disease course, and HIDS should be considered an underlying disease for triggering recurrent MAS attacks. We have also reviewed the current literature regarding HIDS cases complicated with a MAS attack and summarized their demographic, treatment, and outcome characteristics. Key points • Hyperimmunoglobulin D syndrome should be considered in differential diagnosis in patients who experienced recurrent macrophage activation syndrome attacks.

[Mevalonate kinase deficiency]. / Déficit en mévalonate kinase.

MEVALONATE KINASE DEFICIENCY. Mevalonate kinase deficiency is a rare, autosomal recessive, auto- inflammatory disease, linked to mutations in the gene MVK, resulting in the activation of pyrin inflammasome and hypersecretion of interleukin-1ß (IL-1ß). The clinical spectrum realizes a continuum which extends from the mild phenotype of the partial MVK deficiency (hyperimmunoglobulinemia D) resulting in periodic fever syndrome to a letal form of mevalonate aciduria (MA, complete MVK deficiency). Symptoms occur before the age of one, often with a trigger. The partial MVK deficiency (HIDS) is characterized by recurrent episodes of fever with an intense inflammatory syndrome, accompanied with lymphadenopathy, aphthous stomatitis, digestive, articular and cutaneous symptoms. There is in more in mevalonate aciduria a psychomotor retardation, a failure to thrive, a cerebellar ataxia and a dysmorphic syndrome. The diagnosis is based on the mevalonic aciduria during febrile attack and the search for mutations in MVK. The most severe patients can be treated by anti-IL-1.

DÉFICIT EN MÉVALONATE KINASE. Le déficit en mévalonate kinase (MVK) est une maladie autoinflammatoire rare, de transmission autosomique récessive, liée à des mutations dans le gène MVK, aboutissant à une activation de l'inflammasome pyrine et à une hypersécrétion d'interleukine 1ß (IL-1ß). Le spectre clinique est large : de la forme modérée de syndrome avec déficit partiel en MVK (anciennement appelé syndrome hyper-IgD) à des formes létales d'acidurie mévalonique (AM ; déficit complet). Les symptômes surviennent avant l'âge de 1 an, souvent déclenchés par un trigger. Le déficit partiel en MVK comporte des accès de fièvre périodique avec un syndrome inflammatoire important, accompagnés d'adénopathies cervicales, d'une stomatite aphteuse, de signes digestifs, articulaires et cutanés. Il existe également dans l'AM un retard psychomoteur, un retard de croissance, une ataxie et un syndrome dysmorphique. Le diagnostic repose sur la mise en évidence de la mévalonaturie en période fébrile et sur la recherche de mutations dans le MVK. Les patients les plus sévères reçoivent des anti-IL-1.

Ischemic stroke is a potential complication of uncontrolled inflammation in mevalonate kinase deficiency - A case report.

OBJECTIVES: Mevalonate kinase deficiency (MKD) is an autosomal recessive autoinflammatory disease characterized by recurrent systemic inflammation attacks. Despite interconnections with inflammation, thrombosis is rare or underreported in MKD. Our goal is to report evidence of uncontrolled inflammation as the cause of ischemic stroke. MATERIALS AND METHODS: Case report. RESULTS: A 39-year-old French-Canadian patient consulted for stroke. He reported a previous diagnosis of familial Mediterranean fever and hospitalizations nearly monthly since birth for recurrent inflammatory attacks despite colchicine prophylaxis. Attacks were triggered by infections or stress, lasted 3-7 days, and included fever up to 41°C, painful lymphadenopathies, abdominal pain, polyarthralgia and maculopapular rash. Stroke culminated his most recent inflammatory attack. Brain MRI confirmed an acute infarct, without chronic ischemic damage. Blood tests documented increased C-reactive protein, amyloid A and immunoglobulin-D. Prothrombotic and autoantibody tests, cervicocephalic CT-angiography, echocardiography, cardiac monitoring, and toxic screen were unremarkable. Infections were excluded. His only sister had similar attacks. In both cases, sequencing of 32 autoinflammatory-associated genes identified two pathogenic mevalonate kinase mutations. Their non-consanguineous parents, half-brother and four children were asymptomatic. Following treatment with anti-interleukin-1beta monoclonal antibodies, he no longer had inflammatory attacks or stroke in >4 years. CONCLUSION: This MKD patient experienced an ischemic stroke during an attack, attributed to uncontrolled inflammation. Investigations excluded other stroke etiologies. Recurrent febrile attacks starting before age 1 and lasting >3 days, gastrointestinal symptoms, painful lymphadenopathies, maculopapular rash, triggers, aphthous stomatitis, non-Mediterranean ancestry, and ineffectiveness of colchicine prophylaxis are consistent with MKD. Anti-interleukin-1 therapy prevents recurrent autoinflammatory attacks.

Case Report: Comorbid Hyper-IgD Syndrome and Hidradenitis Suppurativa - A New Syndromic Form of HS? A Report of Two Cases.

Hidradenitis Suppurativa (HS) is a chronic suppurative disease of the pilosebaceous unit. The current model of HS pathophysiology describes the condition as the product of hyperkeratinisation and inflammation at the hair follicular unit. Environmental factors (such as smoking and obesity), gender, genetic predisposition, and skin dysbiosis are considered the main pathogenic drivers of the disease. Autoinflammatory syndromes associated with HS are rare but may help to highlight the potential roles of autoinflammation and dysregulated innate immune system in HS. Therefore, it is of major relevance to increase the awareness about these diseases in order to improve the understanding of the disease and to optimize the management of the patients. Herein, we report for the first time, to our knowledge, two clinical cases of Hyper-IgD syndrome-associated HS. Hyper-IgD is an autoinflammatory syndrome caused by a mevalonate kinase deficiency (MKD), a key kinase in the sterol and isoprenoid production pathway. We describe the potentially shared pathophysiological mechanisms underpinning comorbid MKD-HS and propose therapeutic options for the management of these patients.

Neurological manifestations in mevalonate kinase deficiency: A systematic review.

INTRODUCTION: Mevalonate kinase deficiency (MKD) is a monogenic auto-inflammatory disease. Its manifestations range from partial MKD to mevalonic aciduria (MVA). All patients display a periodic fever, and MVA patients additionally exhibit severe neurological involvement. The objective of this work was to describe neurological manifestations of MKD. METHODS: A systematic literature review was performed from January 1990 to January 2022. Forty-five patients from 18 case reports and five cohort studies were included in the analysis. RESULTS: In cohort studies, the most-reported manifestations were headaches (41%) and fatigue (31%). Serious involvements including ataxia and developmental delay were described less than 1% of patients but 22-31% of case reports. They consistently appeared in the first years of life. Retinal dystrophy was frequently reported (31%) in case reports. Other manifestations, including uveitis, aseptic meningitis, and stroke remained rare. DISCUSSION: Severe neurological manifestations are rare in MKD but are responsible for major functional disabilities. They are present at onset and never appear at follow-up of patients with mild MKD. Conversely, headaches and fatigue are frequent symptoms that should be investigated. Visual examinations should be performed on the appearance of visual symptoms. The efficacy of anti-IL-1ß therapy on neurological manifestations should be further investigated.

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.

Homozygous V377I mutation causing mevalonate kinase.

Hyperimmunoglobulinaemia D syndrome (HIDS) is a rare autosomal recessive disorder caused by mutations in the mevalonate kinase (MVK) gene, located on chromosome 12. The most common mutation identified in MVK gene so far is V377I. Compound heterozygotes that include this variant may exhibit a more severe phenotype of the disease and homozygotes are rarely found in clinical practice probably they express a milder phenotype. HIDS is a chronic autoinflammatory disease characterised by recurrent febrile episodes, associated with lymphadenopathies, abdominal pain, rash and arthritis. These flares can be triggered by vaccination, minor trauma, surgery and stress.We report a case of a 2-year-old girl who had recurrent attacks of fever associated with cervical lymphadenopathy, macular erythematous skin rash, abdominal pain and aphthous ulcers in the mouth. The patient was found to excrete elevated amounts of urinary mevalonic acid and a homozygous V337I mutation in the MVK gene was identified.

Uveitis, glaucoma, and cataract with mevalonate kinase deficiency.

We report 7 years of follow-up data on ocular findings in a 2-month-old boy who presented with early-onset bilateral granulomatous panuveitis with subsequent development of secondary glaucoma and total cataract, along with multisystem involvement. He was diagnosed with mevalonate kinase deficiency (MKD), with a homozygous missense variant in exon-6 of the mevalonate kinase (MVK) gene on chromosome-12 that resulted in the substitution of aspartic acid for asparagine at codon 205 (p.Asn205Asp). Despite being managed with topical/systemic steroids and immunosuppression therapy with methotrexate and a short course of adalimumab, the patient continued to develop recurrent episodes of uveitis along with multisystem manifestations. The occurrence of early-onset uveitis is rare, as is the diagnosis of MKD.

Making a diagnosis of periodic fever syndrome: Experience from a single tertiary centre.

AIM: This study aims to evaluate the utility of genetic testing of patients diagnosed with periodic fever syndromes and to assess the validity of existing scoring criteria. METHODS: This study retrospectively reviewed the clinical history of patients diagnosed with periodic fever syndromes at Queensland Children's Hospital between November 2014 and June 2018. RESULTS: Forty-three patients were diagnosed with periodic fever syndromes. Diagnoses in the cohort included periodic fever, adenitis, pharyngitis and aphthous stomatitis (10), tumour necrosis factor receptor-associated periodic syndrome (9), cryopyrin-associated periodic syndrome (6), mevalonate kinase deficiency (4) while 14 remained unspecified. No presenting symptoms were uniquely associated with any particular diagnosis. Genetic testing of between 1 and 26 genes was performed in 26 (60%) patients. Two (7.7%) patients had pathogenic variants identified. Variants of uncertain significance which were insufficient to confirm a monogenic disorder were identified in a further 7 (27%) patients. The Eurofever classification criteria correlated with clinical diagnosis for patients diagnosed with cryopyrin-associated periodic syndrome (P = 0.046) and tumour necrosis factor receptor-associated periodic syndrome (P = 0.025) but not for patients diagnosed with mevalonate kinase deficiency (P = 0.47); however, the Eurofever classification criteria were often positive for more than one diagnosis in these patients. CONCLUSION: The European classification criteria can form a potentially useful tool to guide diagnosis; however, clinical judgement remains essential, because the score is often positive for multiple diagnoses. The diagnostic yield of genetic testing in this cohort was low and genetic testing may be more useful to confirm a strong clinical suspicion than to clarify a diagnosis for patients with less clear symptoms.