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Mevalonate kinase deficiency (MKD), a rare auto-inflammatory disorder, arises from mutations in the MVK gene, disrupting isoprenoid biosynthesis, and affecting cellular processes. This comprehensive review provides an updated perspective on MKD, including its aetiology, pathogenesis, diagnostic modalities, and therapeutic strategies. Based on recent research and clinical advances, our objective is to bridge the knowledge gaps in the 2015 SHARE guidelines. By describing molecular mechanisms, diagnostic dilemmas, and emerging therapies, this article should serve as a resource for clinicians and researchers, promoting a deeper understanding of MKD and guiding optimal patient care. [ABSTRACT FROM AUTHOR]

Abstract Introduction Interim analysis of the long-term safety and effectiveness of canakinumab, at a patient level, in the mevalonate kinase deficiency/hyperimmunoglobulin-D syndrome (MKD/HIDS) cohort of the RELIANCE registry. Methods From June 2018, the RELIANCE registry enrolled paediatric (aged ≥ 2 years) and adult patients (aged ≥ 18 years) with MKD/HIDS who were receiving canakinumab as part of their routine medical care. Safety, physician- and patient-reported measures of disease activity and dosing patterns were evaluated at baseline and every 6 months until end-of-study visit. Results At the analysis cut-off date of December 2022, eight patients with MKD/HIDS were enrolled. Five (62.5%) were children (

Introduction: Interim analysis of the long-term safety and effectiveness of canakinumab, at a patient level, in the mevalonate kinase deficiency/hyperimmunoglobulin-D syndrome (MKD/HIDS) cohort of the RELIANCE registry. Methods: From June 2018, the RELIANCE registry enrolled paediatric (aged ≥ 2 years) and adult patients (aged ≥ 18 years) with MKD/HIDS who were receiving canakinumab as part of their routine medical care. Safety, physician- and patient-reported measures of disease activity and dosing patterns were evaluated at baseline and every 6 months until end-of-study visit. Results: At the analysis cut-off date of December 2022, eight patients with MKD/HIDS were enrolled. Five (62.5%) were children (< 18 years) and five (62.5%) were female. The median patient age was 8.0 (range 2.0–39.0) years, and all patients were pre-treated with canakinumab prior to enrolment (median duration of canakinumab treatment: 3.8 years). Canakinumab was well tolerated, with seven (87.5%) patients reporting 48 adverse events (incidence rate/100 patient years: 218.1). No serious adverse drug reactions were reported. Patients continued to receive vaccinations during long-term treatment with canakinumab. Disease activity, evaluated by physician-reported (physician's global assessment, disease remission, C-reactive protein, serum amyloid A, erythrocyte sedimentation rate) and patient-reported (autoinflammatory disease activity index diary, disease activity, fatigue, impact on social life) measures, was generally well controlled throughout the study. Over 50.0% of patients maintained disease remission from baseline to month 24, and medians of all inflammatory markers remained within normal limits throughout the study. Most patients received higher than the recommended starting dose of canakinumab throughout the study. Conclusion: Data from this interim analysis of a unique registry of patients with a rare disease support the long-term safety and effectiveness of the IL-1-blocking agent canakinumab for the treatment of MKD/HIDS. [ABSTRACT FROM AUTHOR]

Mevalonate kinase deficiency (MKD), a rare auto-inflammatory disorder, arises from mutations in the MVK gene, disrupting isoprenoid biosynthesis, and affecting cellular processes. This comprehensive review provides an updated perspective on MKD, including its aetiology, pathogenesis, diagnostic modalities, and therapeutic strategies. Based on recent research and clinical advances, our objective is to bridge the knowledge gaps in the 2015 SHARE guidelines. By describing molecular mechanisms, diagnostic dilemmas, and emerging therapies, this article should serve as a resource for clinicians and researchers, promoting a deeper understanding of MKD and guiding optimal patient care.

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Background: Fever is one of the most frequent symptoms highlighted during medical assistance. Due to this great impact, our study has the purpose of analyzing the demographic and laboratory characteristics of patients hospitalized in our center and identifying predictive markers to make the differential diagnosis between infectious and non-infectious fever. Methods: Our population included 220 children, collected from January 2017 to August 2022, hospitalized for continuous fever (4 days or more in duration with at least one temperature peak ≥37.5 °C) and excluded cases of discharge against medical advice and/or transfer to other operating units. Demographic (mean age at the time of admission, frequency of hospitalization, and mean days of hospitalization), laboratory, and instrumental variables were analyzed in order to find correlation with fever etiology. Results: Older age at the time of hospitalization, family history of periodic fever, fever lasting more than 8 days, and longer hospitalization are strongly associated with non-infectious fever, together with anemia, high platelet count, high CRP and ferritin, and hyponatremia at the time of admission. Paracetamol is the preferred antipyretic treatment. Echocardiogram has shown anomalies in patients with infectious fever, while ECG anomalies were detected in non-infectious fever. Conclusions: Our data underline the importance of predictive markers, such as clinical and laboratory parameters, to differentiate infectious from non-infectious fevers, but further studies are necessary. [ABSTRACT FROM AUTHOR]

The article discusses the case of a pediatric patient with mevalonate kinase deficiency (MKD) caused by homozygous mutation in the MVK gene. Topics discussed include the patient's development of very early-onset, recurrent episodes and life-threatening colitis, the results of genetic testing and colonoscopic biopsy, and the management of the patient through combination therapy targeting interleukin-1 beta and tumor necrosis factor alpha.

Objective: Bi-allelic pathogenic variants in the MVK gene, which encodes mevalonate kinase (MK), an essential enzyme in isoprenoid biosynthesis, cause the autoinflammatory metabolic disorder mevalonate kinase deficiency (MKD). We generated and characterized MK-deficient monocytic THP-1 cells to identify molecular and cellular mechanisms that contribute to the pro-inflammatory phenotype of MKD. Methods: Using CRISPR/Cas9 genome editing, we generated THP-1 cells with differentMK deficiencies mimicking the severe (MKD-MA) andmild end (MKD-HIDS) of the MKD disease spectrum. Following confirmation of previously established disease-specific biochemical hallmarks, we studied the consequences of the different MK deficiencies on LPS-stimulated cytokine release, glycolysis versus oxidative phosphorylation rates, cellular chemotaxis and protein kinase activity. Results: Similar to MKD patients' cells, MK deficiency in the THP-1 cells caused a pro-inflammatory phenotype with a severity correlating with the residual MK protein levels. In the MKD-MA THP-1 cells, MK protein levels were barely detectable, which affected protein prenylation and was accompanied by a profound pro-inflammatory phenotype. This included a markedly increased LPS-stimulated release of pro-inflammatory cytokines and a metabolic switch from oxidative phosphorylation towards glycolysis. We also observed increased activity of protein kinases that are involved in cell migration and proliferation, and in innate and adaptive immune responses. The MKD-HIDS THP-1 cells had approximately 20% residual MK activity and showed a milder phenotype, which manifested mainly upon LPS stimulation or exposure to elevated temperatures. Conclusion: MK-deficient THP-1 cells show the biochemical and proinflammatory phenotype of MKD and are a good model to study underlying disease mechanisms and therapeutic options of this autoinflammatory disorder. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Mevalonate kinase deficiency (MKD) is an autoinflammatory metabolic disorder caused by bi‐allelic loss‐of‐function variants in the MVK gene, resulting in decreased activity of the encoded mevalonate kinase (MK). Clinical presentation ranges from the severe early‐lethal mevalonic aciduria to the milder hyper‐IgD syndrome (MKD–HIDS), and is in the majority of patients associated with recurrent inflammatory episodes with often unclear cause. Previous studies with MKD–HIDS patient cells indicated that increased temperature, as caused by fever during an inflammatory episode, lowers the residual MK activity, which causes a temporary shortage of non‐sterol isoprenoids that promotes the further development of inflammation. Because an increase of the residual MK activity is expected to make MKD–HIDS patients less sensitive to developing inflammatory episodes, we established a cell‐based screen that can be used to identify compounds and/or therapeutic targets that promote this increase. Using a reporter HeLa cell line that stably expresses the most common MKD–HIDS variant, MK‐V377I, C‐terminally tagged with bioluminescent NanoLuc luciferase (nLuc), we screened the Prestwick Chemical Library®, which includes 1280 FDA‐approved compounds. Multiple compounds increased MK‐V377I‐nLuc bioluminescence, including steroids (i.e., glucocorticoids, estrogens, and progestogens), statins and antineoplastic drugs. The glucocorticoids increased MK‐V377I‐nLuc bioluminescence through glucocorticoid receptor signaling. Subsequent studies in MKD–HIDS patient cells showed that the potent glucocorticoid clobetasol propionate increases gene transcription of MVK and other genes regulated by the transcription factor sterol regulatory element‐binding protein 2 (SREBP‐2). Our results suggest that increasing the flux through the isoprenoid biosynthesis pathway by targeting the glucocorticoid receptor or SREBP‐2 could be a potential therapeutic strategy in MKD–HIDS. [ABSTRACT FROM AUTHOR]

To investigate clinical symptoms and genetic variants in patients from the German anti-IL-1 registry for autoinflammatory orphan diseases (GARROD) between 2013 and 2022. Multicentre, retrospective analysis of demographic, clinical and genetic data of patients with autoinflammatory diseases (AID) who received anti-IL-1 targeted therapy. The cohort comprised 152 patients with familial Mediterranean fever (FMF; n = 71), cryopyrin-associated periodic syndromes (CAPS; n = 43), TNF-receptor associated periodic syndrome (TRAPS; n = 19), mevalonate kinase deficiency (MKD; n = 3) and unclassified AID (uAID; n = 16). Inflammatory attacks started in 61.2% of the patients before the age of 18 years. The delay between the first AID attack and anti-IL-1 therapy was 17.8 years. Monogenetic AIDs were diagnosed by clinical symptoms. Genetic analyses confirmed the diagnosis in 87.3% of patients with FMF, 65.2% with CAPS and 94.8% with TRAPS. Among this group, heterozygous MEFV variants and variants of unknown significance (VUS) were detected in 22.5% of patients with FMF, 51.2% with CAPS and 47.4% with TRAPS. Patients with VUS were older at disease onset which is consistent with a milder phenotype. Twenty-four patients had secondary AA amyloidosis (AA) at initiation of anti-IL-1 therapy. The mean age of these patients was 16.4 years at their first attack and 44.9 years at the time of AA diagnosis. Turkish-Armenian ancestry correlated with MEFV variants and higher FMF disease activity compared to German ancestry. Molecular genetic analyses should substantiate the clinical diagnosis of a monogenetic AID. Our data support the concept of variable penetrance of VUS which can be associated with late-onset AID. [ABSTRACT FROM AUTHOR]

Mevalonate kinase deficiency (MKD) is an exceedingly rare autosomal recessive inborn metabolism error characterized by mutations in the MVK gene, leading to impaired synthesis of cholesterol and isoprenoids. Two case reports of MKD in South India, shedding light on the disease’s clinical heterogeneity are described here. The first case involves an eleven-month-old child with recurrent febrile attacks, joint pain, and a family history of similar complaints. In the second case, a 2-year-old born to consanguineous parents presents with severe manifestations, including joint deformities, developmental delay, and malnutrition. Exome sequencing confirmed the diagnosis, identifying specific mutations in the MVK gene.

Mevalonate kinase deficiency (MKD) is an exceedingly rare autosomal recessive inborn metabolism error characterized by mutations in the MVK gene, leading to impaired synthesis of cholesterol and isoprenoids. Two case reports of MKD in South India, shedding light on the disease's clinical heterogeneity are described here. The first case involves an eleven-month-old child with recurrent febrile attacks, joint pain, and a family history of similar complaints. In the second case, a 2-year-old born to consanguineous parents presents with severe manifestations, including joint deformities, developmental delay, and malnutrition. Exome sequencing confirmed the diagnosis, identifying specific mutations in the MVK gene. [ABSTRACT FROM AUTHOR]

Abstract 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.

ObjectiveBi-allelic pathogenic variants in the MVK gene, which encodes mevalonate kinase (MK), an essential enzyme in isoprenoid biosynthesis, cause the autoinflammatory metabolic disorder mevalonate kinase deficiency (MKD). We generated and characterized MK-deficient monocytic THP-1 cells to identify molecular and cellular mechanisms that contribute to the pro-inflammatory phenotype of MKD.MethodsUsing CRISPR/Cas9 genome editing, we generated THP-1 cells with different MK deficiencies mimicking the severe (MKD-MA) and mild end (MKD-HIDS) of the MKD disease spectrum. Following confirmation of previously established disease-specific biochemical hallmarks, we studied the consequences of the different MK deficiencies on LPS-stimulated cytokine release, glycolysis versus oxidative phosphorylation rates, cellular chemotaxis and protein kinase activity.ResultsSimilar to MKD patients’ cells, MK deficiency in the THP-1 cells caused a pro-inflammatory phenotype with a severity correlating with the residual MK protein levels. In the MKD-MA THP-1 cells, MK protein levels were barely detectable, which affected protein prenylation and was accompanied by a profound pro-inflammatory phenotype. This included a markedly increased LPS-stimulated release of pro-inflammatory cytokines and a metabolic switch from oxidative phosphorylation towards glycolysis. We also observed increased activity of protein kinases that are involved in cell migration and proliferation, and in innate and adaptive immune responses. The MKD-HIDS THP-1 cells had approximately 20% residual MK activity and showed a milder phenotype, which manifested mainly upon LPS stimulation or exposure to elevated temperatures.ConclusionMK-deficient THP-1 cells show the biochemical and pro-inflammatory phenotype of MKD and are a good model to study underlying disease mechanisms and therapeutic options of this autoinflammatory disorder.

Simple Summary: This article addresses the topic of primary immunodeficiencies, with particular emphasis on antibody deficiencies with near-normal immunoglobulin levels or hyperimmunoglobulinemia. This paper goes beyond genetics and emphasizes the importance of the immune system and particularly immune checkpoints and Epstein–Barr virus (EBV) reactivation in the context of these disorders. The article delves into the immune dysregulations occurring in the course of this type of disease and the potential role of EBV reactivation, which affects the clinical picture of patients and, in the future, may contribute to the development of cancer, especially those related to hematological malignancies. Disturbances observed in the immunopathogenesis of the presented diseases go beyond the accepted scheme, with the development of PID largely associated only with genetic disorders, and the article emphasizes that the regulation of immunity and virus reactivation also contributes to the progression of PID. This study delves into the intricate landscape of primary immunodeficiencies, with a particular focus on antibody deficiencies characterized by near-normal immunoglobulin levels or hyperimmunoglobulinemia. Contrary to the conventional focus on genetic dysregulation, these studies investigate the key roles of immune checkpoints, such as PD-1/PD-L1, CTLA-4/CD86, and CD200R/CD200, on selected subpopulations of T and B lymphocytes and their serum concentrations of soluble forms in patients recruited for the studies in healthy volunteers. In addition, the studies also show the role of Epstein–Barr virus (EBV) reactivation and interactions with tested pathways of immune checkpoints involved in the immunopathogenesis of this disease. By examining the context of antibody deficiencies, this study sheds light on the nuanced interplay of factors beyond genetics, particularly the immune dysregulations that occur in the course of this type of disease and the potential role of EBV reactivation, which affects the clinical presentation of patients and may contribute to the development of cancer in the future, especially related to hematological malignancies. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Objective The presence of FMF cases without MEFV (MEFV innate immunity regulator, pyrin) pathogenic variants led us to search for other genes' involvement in the disease development. Here, we describe the presence of genetic heterogeneity in a three-generation family with an FMF/mevalonate kinase deficiency (MKD)-overlapping phenotype without MEFV/MVK (mevalonate kinase) pathogenic variants. Method Targeted sequencing revealed a rare, fully penetrant variant in PSTPIP1 (p.Arg228Cys, rs781341816). Computational stability analyses of PSTPIP1 protein were performed. PSTPIP1-pyrin protein interaction was examined by immunoprecipitation and immunoblotting in peripheral blood mononuclear cells (PBMCs) of patients and healthy controls. PBMCs were cultured, and inflammation was induced by LPS+ATP treatment, followed by protein level measurements of caspase-1, IL1ß, pyrin and PSTPIP1 in cell lysates and mature caspase-1 and mature IL1ß in supernatants. Results The conserved, rare (GnomAD, 0.000028) PSTPIP1 p.Arg228Cys variant, previously reported in ClinVar as a variant with uncertain significance, showed complete penetrance in the family presenting an autosomal dominant pattern. Computational analyses showed a potentially destabilizing effect of the variant on PSTPIP1 protein. Accordingly, PSTPIP1-pyrin interaction was increased in patients harboring the variant, which resulted in elevated levels of mature caspase-1 and IL1ß in the inflammation-induced patient samples. Conclusions Unlike previously described cases with pyogenic arthritis, pyoderma gangrenosum, and acne (PAPA)-associated PSTPIP1 variants, our patients with the p.Arg228Cys variant presented with an FMF/MKD-overlapping phenotype. As additional data on the genetic heterogeneity in the variable clinical spectrum of autoinflammatory syndromes, we suggest that the p.Arg228Cys variant in PSTPIP1 is related to inflammation responses through strong PSTPIP1 -pyrin interaction and pyrin inflammasome activation. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract Mevalonate kinase (MK) deficiency is a rare autosomal recessive metabolic disorder caused by pathogenic variants in the MVK gene with a broad phenotypic spectrum including autoinflammation, developmental delay and ataxia. Typically, neurological symptoms are considered to be part of the severe end of the phenotypical spectrum and are reported to be in addition to the autoinflammatory symptoms. Here, we describe a patient with MK deficiency with severe neurological symptoms but without autoinflammation and we found several similar patients in the literature. Possibly, the non‐inflammatory phenotype is related to a specific genotype: the MVK p.(His20Pro)/p.(Ala334Thr) variant. There is probably an underdetection of the neurological MK deficient phenotype without inflammatory symptoms as clinicians may not test for MK deficiency when patients present with only neurological symptoms. In conclusion, although rare, neurological symptoms without hyperinflammation might be more common than expected in MK deficiency. It seems relevant to consider MK deficiency in patients with psychomotor delay and ataxia, even if there are no inflammatory symptoms.

Objectives: This study aims to investigate a genetic panel in patients with periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) syndrome and examine its performance for an accurate differential diagnosis. Patients and methods: Between January 2021 and January 2022, a total of 104 children with PFAPA syndrome (63 males, 41 females; mean age: 4.8±2.3 years; range, 1.2 to 8.9 years) were retrospectively analyzed. Next-generation sequencing test was performed using a custom QIAGEN-QIAseq™? Targeted DNA Panel which includes six genes namely ELANE, LPIN2, MEFV, MVK, NLRP3, and TNFRSF1A. Results: Of 104 patients, 38 (36.5%) had variants in the genetic panel. The most common variants were found in the MEFV gene (n=35, 33.6%), the most frequent genotype was E148Q heterozygosity (n=16). Four and two patients were eventually diagnosed with Familial Mediterranean fever (FMF) and hyperimmunoglobulin D syndrome (HIDS), since they had confirmative biallelic pathogenic in the MEFV and MVK genes, respectively. Conclusion: A genetic panel, including MEFV and MVK genes, may be useful in patients, clinically resembling PFAPA, since they may have HIDS or FMF, but lack typical features of the exact disease. Nonetheless, we believe that distinct genetic panels should be developed for different populations. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to investigate the potential effect of the mevalonate kinase (MVK) gene polymorphisms on the pathogenesis and clinical findings in ankylosing spondylitis (AS) patients. Patients and methods: This cross-sectional study was conducted with 103 participants (63 males, 40 females) between January 2013 and January 2014. Of these, 51 (32 males, 19 females; mean age: 37.3±10.2 years; range, 19 to 60 years) were adult AS patients who met the 1984 Modified New York Criteria, and 52 (31 males, 21 females; mean age: 33.8±12 years; range, 19 to 60 years) were healthy volunteers with similar demographics. MVK gene analysis was performed using polymerase chain reaction sequencing by isolating deoxyribonucleic acids from peripheral blood samples. We determined serum immunoglobulin (Ig)D levels using radial immunodiffusion. We performed physical examinations on the AS patients. The Bath Ankylosing Spondylitis Disease Activity Index and the Bath Ankylosing Spondylitis Functional Index forms were filled and erythrocyte sedimentation rate, C-reactive protein, and IgD levels were recorded. Results: There was no statistically significant difference in the mean age between the groups (p=0.121). The frequency of symptomatic single nucleotide polymorphisms (SNPs), c.769-38 C>T heterozygous, c.769-7 T>G heterozygous, and c.769-38 C>T homozygous were similar between the groups (15/15; p=0.646). Nonsymptomatic SNPs were more common in the patient group, but the difference was not significant (83/58; p>0.05). The rate of having an MVK gene polymorphism was 36 (70.6%) in the AS compared to the 33 (63.4%) in the control group (p>0.05). There were no associations in clinical findings between the AS patients with or without MVK gene polymorphisms. New heterozygous SNPs, I56V A>G, E281D G>D, V80I G>A, and C173Y G>A, were present in four AS patients. Conclusion: The frequency of MVK gene polymorphisms was higher in AS patients than in healthy controls. But there was no statistically significant difference. We determined no effect of the present polymorphisms on AS clinical and laboratory findings. [ABSTRACT FROM AUTHOR]

Objectives: To assess the real-world safety and effectiveness of canakinumab in patients in Japan with tumour necrosis factor receptor-associated periodic syndrome (TRAPS) or mevalonate kinase deficiency/hyperimmunoglobulinaemia D with periodic fever syndrome (MKD/HIDS). Methods: All patients with TRAPS or MKD/HIDS who received canakinumab following drug approval in Japan were registered in a post-marketing all-patient surveillance with a 2-year observation period. Herein, the interim results are reported. Results: Fifteen patients with TRAPS and seven with MKD/HIDS were included in the safety and effectiveness analysis set. Adverse drug reactions were reported in 26.67% (n = 4) and 42.86% (n = 3) of TRAPS and MKD/HIDS patients, respectively. Most common adverse drug reactions were upper respiratory tract inflammation (13.33%, n = 2) and pyrexia (42.86%, n = 3) in TRAPS and MKD/HIDS patients, respectively. No serious adverse drug reactions were observed in either TRAPS or MKD/HIDS patients. The proportion of responders was 46.67% and 14.29% in the TRAPS and MKD/HIDS groups, respectively; 72.73% and 66.67% achieved clinical remission, while 90.91% and 66.67% achieved serological remission by Week 4 in the TRAPS and MKD/HIDS groups, respectively. Conclusions: These interim results provide the first evidence of the real-world effectiveness of canakinumab in patients with TRAPS or MKD/HIDS in Japan. No new safety concerns were identified. [ABSTRACT FROM AUTHOR]

Mevalonate kinase (MK)-associated diseases encompass a broad spectrum of rare auto-inflammatory conditions, all resulting from pathogenic variants in the mevalonate kinase gene (MVK). Their clinical manifestations are highly variable, ranging from more or less serious systemic disorders, such as hereditary recurrent fevers, to purely localized pathologies such as porokeratosis. The oldest condition identified as linked to this gene is a metabolic disease called mevalonic aciduria, and the most recent is disseminated superficial actinic porokeratosis, a disease limited to the skin. The modes of inheritance of MK-associated diseases also diverge among the different subtypes: recessive for the systemic subtypes and dominant with a post-zygotic somatic genetic alteration for MVK-associated porokeratosis. This review quickly retraces the historical steps that led to the description of the various MK-associated disease phenotypes and to a better understanding of their pathophysiology, then summarizes and compares the different genetic mechanisms involved in this group of disorders, and finally discusses the diverse causes that could underlie this phenotypic heterogeneity.

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. [ABSTRACT FROM AUTHOR]

Systemic autoinflammatory diseases (SAIDs) are defined by recurrent febrile attacks associated with protean manifestations involving joints, the gastrointestinal tract, skin, and the central nervous system, combined with elevated inflammatory markers, and are caused by a dysregulation of the innate immune system. From a clinical standpoint, the most known SAIDs are familial Mediterranean fever (FMF); cryopyrin-associated periodic syndrome (CAPS); mevalonate kinase deficiency (MKD); and periodic fever, aphthosis, pharyngitis, and adenitis (PFAPA) syndrome. Current guidelines recommend the regular sequential administration of vaccines for all individuals with SAIDs. However, these patients have a much lower vaccination coverage rates in 'real-world' epidemiological studies than the general population. The main purpose of this review was to evaluate the scientific evidence available on both the efficacy and safety of vaccines in patients with SAIDs. From this analysis, neither serious adverse effects nor poorer antibody responses have been observed after vaccination in patients with SAIDs on treatment with biologic agents. More specifically, no new-onset immune-mediated complications have been observed following immunizations. Post-vaccination acute flares were significantly less frequent in FMF patients treated with colchicine alone than in those treated with both colchicine and canakinumab. Conversely, a decreased risk of SARS-CoV-2 infection has been proved for patients with FMF after vaccination with the mRNA-based BNT162b2 vaccine. Canakinumab did not appear to affect the ability to produce antibodies against non-live vaccines in patients with CAPS, especially if administered with a time lag from the vaccination. On the other hand, our analysis has shown that immunization against Streptococcus pneumoniae, specifically with the pneumococcal polysaccharide vaccine, was associated with a higher incidence of adverse reactions in CAPS patients. In addition, disease flares might be elicited by vaccinations in children with MKD, though no adverse events have been noted despite concurrent treatment with either anakinra or canakinumab. PFAPA patients seem to be less responsive to measles, mumps, and rubella-vaccine, but have shown higher antibody response than healthy controls following vaccination against hepatitis A. In consideration of the clinical frailty of both children and adults with SAIDs, all vaccinations remain 'highly' recommended in this category of patients despite the paucity of data available. [ABSTRACT FROM AUTHOR]

Objective Auto-inflammatory diseases (AIDs) result from mutations in genes of the innate immune system leading to periodic multisystemic inflammation. We aimed to describe the clinical, biological and molecular features (when available) and outcomes of Moroccan patients with AIDs. Methods Patient data were collected retrospectively and analysed over a 13-year period. Results Among 30 patients, 60% had FMF, 16% mevalonate kinase deficiency (MKD) and 24% other AIDs. The mean age at first consultation was 6.9 years, and the mean diagnostic delay was 3 years. Consanguinity was reported in 16 cases. IgA vasculitis was associated with 33% of FMF patients, in whom the main clinical features were fever (88.8%), abdominal pain (100%), arthralgias (88.8%) and arthritis (50%), and the most frequent mutation was M694V (66%). All FMF patients were treated with colchicine. Most MKD patients were confirmed by elevated urinary mevalonic acid levels, and four of five MKD patients received targeted therapy. Chronic recurrent osteomyelitis patients were confirmed by radiological and histological analysis. Two cases of Marshall syndrome were diagnosed according to validated criteria. A case of familial pustular psoriasis was diagnosed based on histological analysis and a patient with Muckle–Wells syndrome by clinical features. The outcome was favourable in 76%, partial in 13%, and three deaths were reported. Conclusion FMF and MKD are the most reported diseases. AIDs are probably underestimated because they are unknown to clinicians. The aim of this work is to raise awareness among paediatricians about AIDs and create a network for best practice. [ABSTRACT FROM AUTHOR]

Non‐syndromic retinitis pigmentosa (NSRP) is a clinically and genetically heterogeneous group of disorders characterized by progressive degeneration of the rod and cone photoreceptors, often leading to blindness. The evolving association of syndromic genes to cause NSRP and the increasing role of intronic variants in explaining missing heritability in genetic disorders present challenges in establishing conclusive clinical and genetic diagnoses. This study sought to identify and validate the causative genetic variant(s) in a 13‐year‐old male initially diagnosed with NSRP. Genome sequencing identified a pathogenic missense variant in MVK [NM_000431.3:c.803T>C (p.Ile268Thr)], in trans with a novel intronic variant predicted to create a new donor splice site (c.768+71C>A). Proband cDNA analysis confirmed the inclusion of the first 68 base pairs of intron 8 that resulted in a frameshift in MVK (r.768_769ins[768+1_768+68]) and significantly reduced the expression of reference transcript (17.6%). Patient re‐phenotyping revealed ataxia, cerebellar atrophy, elevated urinary mevalonate and LTE4, in keeping with mild mevalonic aciduria and associated syndromic retinitis pigmentosa. Leakage of reference transcript likely explains the milder phenotype observed in our patient. This is the first association of a deep intronic splice variant to cause MVK‐related disorder. This report highlights the importance of variant validation and patient re‐phenotyping in establishing accurate diagnosis in the era of genome sequencing. [ABSTRACT FROM AUTHOR]

Abstract Background Mevalonate kinase deficiency (MKD) is a rare autoinflammatory condition caused by biallelic loss-of-function (LOF) mutations in mevalonate kinase (MVK) gene encoding the enzyme mevalonate kinase. Patients with MKD display a variety of non-specific clinical manifestations, which can lead to diagnostic delay. We report the case of a child presenting with vasculitis that was found by genetic testing to be caused by MKD, and now add this autoinflammatory disease to the ever-expanding list of causes of monogenic vasculitides. Case presentation A 2-year-old male presented with an acute 7-day history of high-grade fever, abdominal pain, diarrhoea, rectal bleeding and extensive purpuric and necrotic lesions, predominantly affecting the lower limbs. He had been suffering from recurrent episodes of fever from early in infancy, associated with maculopapular/petechial rashes triggered by intercurrent infection, and after vaccines. Extensive infection screen was negative. Skin biopsy revealed small vessel vasculitis. Visceral digital subtraction arteriography was normal. With a diagnosis of severe idiopathic cutaneous vasculitis, he was treated with corticosteroids and mycophenolate mofetil. Despite that his acute phase reactants remained elevated, fever persisted and the vasculitic lesions progressed. Next-generation sequencing revealed compound heterozygous mutation in MVK c.928G > A (p.V310M) and c.1129G > A (p.V377I) while reduced mevalonate enzyme activity was confirmed suggesting a diagnosis of MKD as a cause of the severe vasculitis. Prompt targeted treatment with IL-1 blockade was initiated preventing escalation to more toxic vasculitis therapies and reducing unnecessary exposure to cytotoxic treatment. Conclusions Our report highlights the broad clinical phenotype of MKD that includes severe cutaneous vasculitis and emphasizes the need to consider early genetic screening for young children presenting with vasculitis to exclude a monogenic vasculitis which may be amenable to targeted treatment.

Mevalonate kinase deficiency (MKD) is characterized by recurrent fevers and flares of systemic inflammation, caused by biallelic loss-of-function mutations in MVK. The underlying disease mechanisms and triggers of inflammatory flares are poorly understood because of the lack of in vivo models. We describe genetically modified mice bearing the hypomorphic mutation p.Val377Ile (the commonest variant in patients with MKD) and amorphic, frameshift mutations in Mvk. Compound heterozygous mice recapitulated the characteristic biochemical phenotype of MKD, with increased plasma mevalonic acid and clear buildup of unprenylated GTPases in PBMCs, splenocytes, and bone marrow. The inflammatory response to LPS was enhanced in compound heterozygous mice and treatment with the NLRP3 inflammasome inhibitor MCC950 prevented the elevation of circulating IL-1β, thus identifying a potential inflammasome target for future therapeutic approaches. Furthermore, lines of mice with a range of deficiencies in mevalonate kinase and abnormal prenylation mirrored the genotype-phenotype relationship in human MKD. Importantly, these mice allowed the determination of a threshold level of residual enzyme activity, below which protein prenylation is impaired. Elevated temperature dramatically but reversibly exacerbated the deficit in the mevalonate pathway and the defective prenylation in vitro and in vivo, highlighting increased body temperature as a likely trigger of inflammatory flares. [ABSTRACT FROM AUTHOR]

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Abstract Background Although canakinumab has demonstrated efficacy in multiple trials in patients with periodic fever syndromes (PFS), the evidence on initiation of canakinumab among PFS patients in real world setting is not well understood. We aimed to characterize the reasons for canakinumab initiation among patients with PFS, specifically, cryopyrin-associated periodic syndrome (CAPS), hyperimmunoglobulin D syndrome/mevalonate kinase deficiency (HIDS/MKD), TNF receptor-associated periodic syndrome (TRAPS) and familial Mediterranean fever (FMF). Methods Physicians retrospectively reviewed the medical charts of PFS patients prescribed canakinumab between 2016 and 2018. Information collected included patient clinical characteristics, reasons for previous treatment discontinuation and canakinumab initiation. The results were summarized for overall patients, and by children (

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. [ABSTRACT FROM AUTHOR]

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. 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. 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. 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-1β therapy on neurological manifestations should be further investigated. [ABSTRACT FROM AUTHOR]

Objectives To evaluate the long-term efficacy and safety of canakinumab in patients with mevalonate kinase deficiency during the open label extension (weeks 41–113) of the randomized controlled CLUSTER trial. Methods During a 72-week period, patients received open-label canakinumab 150 or 300 mg, every 4 or 8 weeks. The disease activity was evaluated every 8 weeks using physician global assessment and counting the number of flares. Concentrations of CRP and serum amyloid A protein were measured. The safety was studied by determination and classification of observed adverse events. The safety and efficacy were analysed separately in three subgroups of patients receiving a cumulative dose of less than <35 mg/kg, ≥35 to <70 mg/kg or ≥70 mg/kg. Results Of the 74 patients who started the CLUSTER study, 66 entered Epoch 4 and 65 completed it. During the 72-week period, 42 (64%) patients experienced no flares, while 13 (20%) had one flare, as compared with a median of 12 flares per year reported at baseline. Low physician global assessment scores were seen at the end of the study for all groups with >90% reporting minimal disease activity or none at all. Median CRP concentrations were consistently equal or lower than 10 mg/l, while median serum amyloid A concentrations remained only slightly above the normal range of 10 mg/l. The study showed no new or unexpected adverse events. Conclusion Canakinumab proved effective to control disease activity and prevent flares in mevalonate kinase deficiency during the 72-week study period. No new safety concerns were reported. Trial registration NCT02059291. https://clinicaltrials.gov. [ABSTRACT FROM AUTHOR]

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.

Autoinflammatory syndromes result from a defective innate immune system. They are characterised by unexplained fever and systemic inflammation involving the skin, muscle, joints, serosa and eyes, along with elevated acute phase reactants. Autoinflammatory syndromes are increasingly recognised as a cause of neurological disease with a diverse range of manifestations. Corticosteroids, colchicine and targeted therapies are effective if started early, and hence the importance of recognising these syndromes. Here, we review the neurological features of specific autoinflammatory syndromes and our approach (as adult neurologists) to their diagnosis. [ABSTRACT FROM AUTHOR]

The article presents a case study of eight pediatric cases initially diagnosed with Kawasaki disease (KD) but later confirmed to have underlying autoinflammatory diseases (AIDs). It is reported that the patients exhibited recurrent febrile episodes, posing a diagnostic challenge. It further underscores the importance of considering AIDs in fevers of unknown origin.

Background: Mevalonate kinase deficiency (MKD) is a rare autoinflammatory condition caused by biallelic loss-of-function (LOF) mutations in mevalonate kinase (MVK) gene encoding the enzyme mevalonate kinase. Patients with MKD display a variety of non-specific clinical manifestations, which can lead to diagnostic delay. We report the case of a child presenting with vasculitis that was found by genetic testing to be caused by MKD, and now add this autoinflammatory disease to the ever-expanding list of causes of monogenic vasculitides. Case presentation: A 2-year-old male presented with an acute 7-day history of high-grade fever, abdominal pain, diarrhoea, rectal bleeding and extensive purpuric and necrotic lesions, predominantly affecting the lower limbs. He had been suffering from recurrent episodes of fever from early in infancy, associated with maculopapular/petechial rashes triggered by intercurrent infection, and after vaccines. Extensive infection screen was negative. Skin biopsy revealed small vessel vasculitis. Visceral digital subtraction arteriography was normal. With a diagnosis of severe idiopathic cutaneous vasculitis, he was treated with corticosteroids and mycophenolate mofetil. Despite that his acute phase reactants remained elevated, fever persisted and the vasculitic lesions progressed. Next-generation sequencing revealed compound heterozygous mutation in MVK c.928G > A (p.V310M) and c.1129G > A (p.V377I) while reduced mevalonate enzyme activity was confirmed suggesting a diagnosis of MKD as a cause of the severe vasculitis. Prompt targeted treatment with IL-1 blockade was initiated preventing escalation to more toxic vasculitis therapies and reducing unnecessary exposure to cytotoxic treatment. Conclusions: Our report highlights the broad clinical phenotype of MKD that includes severe cutaneous vasculitis and emphasizes the need to consider early genetic screening for young children presenting with vasculitis to exclude a monogenic vasculitis which may be amenable to targeted treatment. [ABSTRACT FROM AUTHOR]