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Objectives: Patients with inherited metabolic disorders (IMDs) may require emergency hospital care to prevent life-threatening situations such as metabolic decompensation. To date, over one thousand different rare IMDs have been identified, which means that healthcare professionals (HCPs) initiating emergency treatment may not be familiar with these conditions. The objective of this initiative was to provide HCPs with practical guidance for the acute management of children and adults with IMDs who need emergency care, regardless of the underlying reason., Methods: We outline how a multidisciplinary working group from the French IMDs Healthcare Network for Rare Diseases, known as G2M, has created concise and standardized protocols _each consisting of a single double-sided A4 sheet _ focused on a specific disease, a group of diseases, or a particular symptom. Prior to validation, these protocols were reviewed by all French reference and competence centres for IMDs, as well as by medical experts from other specialities when necessary, physicians from emergency and intensive care units, and representatives from patient associations., Results and Conclusion: In total, 51 emergency protocols containing essential information have been developed and provided to affected patients. All the emergency protocols are freely available in both French and English at https://www.filiere-g2m.fr/urgences. These standardized protocols aim to enhance the emergency care of patients without delay, while also assisting HCPs by increasing their confidence and efficiency, minimizing the risk of dosage errors when administering specialized treatments, saving time, and reducing the number of phone calls to metabolic medicine specialists on night duty. The protocols are scheduled for annual review to facilitate further improvements based on feedback from HCPs and patients, as well as to accommodate any changes in management practices as they evolve., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest related to the content of this manuscript. Within the past 36 months, outside of the submitted work: Juliette Bouchereau reports support for attending a meeting from Ultragenyx; Karine Mention reports a research contract with Sanofi, fees for lectures from Sanofi and Chiesi, and participation in a Board for Chiesi; Jérémy Do Cao reports support for attending a meeting and fees for a presentation at this meeting, both from Sanofi Rare Diseases; Aline Cano reports fees for presentations from Sanofi and Genzyme, honorarium for participation in a Scientific Board from Sanofi, and medical writing fees from Nutricia; Célia Hoebeke reports registration and presentation fees from BioMarin for a meeting, registration fees from Sanofi Aventis France, and a meal offered by Orphalan during another meeting; Anaïs Brassier reports fees for lectures from Sanofi and BioMarin, support for attending meetings from Sanofi, and participation in an Advisory Board for Sanofi; Laurent Gouya reports having participated for free in a Scientific Committee for Alnylam Pharmaceuticals and in the IPNET Executive Board, and having been Chairman of the GenOmics Committee of Foundation For Rare Diseases (FFRD, Fondation Maladies Rares); Jean-Baptiste Arnoux reports fees for lectures from Sanofi and Recordati, consulting fees from Sobi, Immedica pharma and Zealand pharma, and support for attending meetings from Immedica pharma; Cécile Acquaviva-Bourdain reports consulting fees from Alnylam Pharmaceuticals, Ultragenix, and Novodordisk, and fees for lectures from Alnylam Pharmaceuticals; Pierre Broué reports payments to the institution that employs him from Mirium Pharma, and personal fees for Advisory Boards from Mirum Pharma and Albireo AB; Claire Douillard reports grants from Sanofi and Ultragenyx, fees for a presentation from Alnylam Pharmaceuticals, and support for attending a meeting from Sanofi., (Copyright © 2024. Published by Elsevier Inc.)

Background: Classical infantile-onset Pompe disease (IOPD) is the most severe form of Pompe disease. Enzyme replacement therapy (ERT) has significantly increased survival but only a few studies have reported long-term outcomes., Methods: We retrospectively analyzed the outcomes of classical IOPD patients diagnosed in France between 2004 and 2020., Results: Sixty-four patients were identified. At diagnosis (median age 4 months) all patients had cardiomyopathy and most had severe hypotonia (57 of 62 patients, 92%). ERT was initiated in 50 (78%) patients and stopped later due to being ineffective in 10 (21%). Thirty-seven (58%) patients died during follow-up, including all untreated and discontinued ERT patients, and 13 additional patients. Mortality was higher during the first 3 years of life and after the age of 12 years. Persistence of cardiomyopathy during follow-up and/or the presence of heart failure were highly associated with an increased risk of death. In contrast, cross-reactive immunologic material (CRIM)-negative status (n = 16, 26%) was unrelated to increased mortality, presumably because immunomodulation protocols prevent the emergence of high antibody titers to ERT. Besides survival, decreased ERT efficacy appeared after the age of 6 years, with a progressive decline in motor and pulmonary functions for most survivors., Conclusions: This study reports the long-term follow-up of one of the largest cohorts of classical IOPD patients and demonstrates high long-term mortality and morbidity rates with a secondary decline in muscular and respiratory functions. This decreased efficacy seems to be multifactorial, highlighting the importance of developing new therapeutic approaches targeting various aspects of pathogenesis., (© 2023 The Authors. European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.)

Background and Objective: GLUT1 deficiency syndrome (Glut1DS) is a treatable neurometabolic disease that causes a wide range of neurologic symptoms in children and adults. However, its diagnosis relies on an invasive test, that is, a lumbar puncture (LP) to measure glycorrhachia, and sometimes complex molecular analyses of the SLC2A1 gene. This procedure limits the number of patients able to receive the standard of care. We wished to validate the diagnostic performance of METAglut1, a simple blood test that quantifies GLUT1 on the erythrocyte surface., Methods: We performed a multicenter validation study in France, involving 33 centers. We studied 2 patient cohorts: a prospective cohort consisting of patients with a clinical suspicion of Glut1DS explored through the reference strategy, that is, LP and analyses of the SLC2A1 gene, and a retrospective cohort that included patients previously diagnosed with Glut1DS. All patients were blind-tested with METAglut1., Results: We analyzed 428 patients in the prospective cohort, including 15 patients newly diagnosed with Glut1DS, and 67 patients in the retrospective cohort. METAglut1 was 80% sensitive and >99% specific for the diagnosis of Glut1DS. Concordance analyses showed a substantial agreement between METAglut1 and glycorrhachia. In the prospective cohort, the positive predictive value of METAglut1 was slightly higher than that of glycorrhachia. METAglut1 succeeded to identify patients with Glut1DS with SCL2A1 mosaicism and variants of unknown significance., Discussion: METAglut1 is an easily performed, robust, and noninvasive diagnostic test for the diagnosis of Glut1DS, which allows wide screening of children and adults, including those with atypical forms of this treatable condition., Classification of Evidence: This study provides Class I evidence that a positive METAglut1 test accurately distinguishes patients with suspected GLUT1 deficiency syndrome from other neurologic syndromes as compared with invasive and genetic testing., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.)

Objective: The objective of this study was to compare the quality of life (QoL) for parents of children with inborn errors of metabolism (IEMs) requiring a restricted diet with French population norms and investigate parental QoL determinants., Study Design: This cross-sectional study included mothers and/or fathers of children < 18 years of age affected by IEMs requiring a restricted diet (except phenylketonuria) from January 2015 to December 2017. Parents' QoL was assessed using the World Health Organization Quality of Life BREF questionnaire and compared with age- and sex-matched reference values from the French general population. Linear mixed models were used to examine the effects of demographic, socioeconomic, disease-related, and psychocognitive factors on parental QoL, according to a 2-level regression model considering individuals (parents) nested within families., Results: Of the 1156 parents invited to participate, 785 (68%) were included. Compared with the general population, parents of children with IEMs requiring a restricted diet reported a lower QoL in physical and social relationship domains but a higher QoL in the psychological domain. In the multivariate analysis, characteristics associated with poorer parental QoL included both parent-related factors (being a father, older age, more educated parent, nonworking parent, greater anxiety, seeking more social support, and using less positive thinking and problem-solving coping strategies) and family-related factors (disease complications, increased number of hospital medical providers, child's younger age, single-parent family, and lower family material wealth)., Conclusion: Parents of children with IEMs requiring a restricted diet reported poorer QoL in physical and social relationship domains than population norms. Psychocognitive factors, beyond disease-specific and family-related characteristics, were the most important determinants influencing parental QoL and may represent essential aspects for interventions., Clinical Trial Registration: ClinicalTrials.gov: NCT02552784., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Isolated complex III defect is a relatively rare cause of mitochondrial disorder. New genes involved were identified in the last two decades, with only a few cases described for each deficiency. UQCRC2, which encodes ubiquinol-cytochrome c reductase core protein 2, is one of the eleven structural subunits of complex III. We report seven French patients with UQCRC2 deficiency to complete the phenotype reported so far. We highlight the similarities with neoglucogenesis defect during decompensations - hypoglycaemias, liver failure and lactic acidosis - and point out the rapid improvement with glucose fluid infusion, which is a remarkable feature for a mitochondrial disorder. Finally, we discuss the relevance of coenzyme Q10 supplementation in this defect., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier B.V. and Mitochondria Research Society. All rights reserved. All rights reserved.)

Objective: To investigate the determinants of quality of life (QoL) in children with inborn errors of metabolism with restricted diet (IEMRDs) using a single theory-based multidimensional model., Study Design: In this multicenter cross-sectional study, data from children aged 8-17 years with IEMRDs (except phenylketonuria) and their parents were collected from January 2015 to December 2017. Measurements included a child's self-reported QoL, self-rated behavioral problems and anxiety, and parental anxiety. Based on hypotheses from a literature-built theoretical model linking demographic, clinical, family environment, and psychosocial characteristics to QoL either directly or indirectly, associations of these factors with a child's self-rated QoL were examined using a structural equation modeling approach., Results: A total of 312 children (mean [SD] age, 12.2 [2.6] years; 51% boys [n = 160]) were included. Higher levels of trait anxiety and behavioral problems in children were the most important factors associated with poorer QoL (standardized path coefficients, -0.71 and -0.23, respectively). In addition, higher parent trait anxiety, younger age at diagnosis, and a disease requiring an emergency diet were associated with poorer QoL in these children. The final model fit the data closely according to conventional goodness-of-fit statistics and explained 86% of the QoL variance., Conclusions: Psychosocial factors appear to be major determinants of QoL impairment in children with IEMRDs. These factors should be addressed in clinical practice as part of the global treatment plan for a child with IEMRD. Future studies based on a longitudinal design should consider coping strategies when exploring potential predictive factors of QoL., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Introduction: Aminoacyl transfer RNA (tRNA) synthetases are associated with diseases when mutations occur in their encoding genes. Pulmonary alveolar proteinosis can be caused by mutation in the methionyl-tRNA synthetase (MARS) gene while mutations in the leucine-tRNA synthetase (LARS) gene lead to infantile liver failure syndrome type 1. We report the case of a patient with LARS1 pathogenics variants and two patients with MARS1 pathogenics variants. The aim of this study was to analyze the phenotypes of our three patients in detail and classify cases in the literature using Human Phenotype Ontology (HPO) terms., Results: The first patient has two previously undescribed heterozygous variants in LARS1 (c.1818dup and c.463A>G). The other two patients' MARS1 variants (c.1177G>A and c.1700C>T) have already been described in the literature. All three patients had anemia, hepatomegaly, feeding difficulties, failure to thrive and hypoalbuminemia. Including ours, 65 patients are described in total, for whom 117 phenotypic abnormalities have been described at least once, 41.9% of which both in patients with LARS1 and MARS1 mutations., Conclusion: Patients with LARS1 and MARS1 mutations seem to share a common phenotype but further deep phenotyping studies are required to clarify the details of these complex pathologies., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

TANGO2 disease is a severe inherited disorder associating multiple symptoms such as metabolic crises, encephalopathy, cardiac arrhythmias, and hypothyroidism. The mechanism of action of TANGO2 is currently unknown. Here, we describe a cohort of 20 French patients bearing mutations in the TANGO2 gene. We found that the main clinical presentation was the association of neurodevelopmental delay (n = 17), acute metabolic crises (n = 17) and hypothyroidism (n = 12), with a large intrafamilial clinical variability. Metabolic crises included rhabdomyolysis (15/17), neurological symptoms (14/17), and cardiac features (12/17; long QT (n = 10), Brugada pattern (n = 2), cardiac arrhythmia (n = 6)) that required intensive care. We show previously uncharacterized triggers of metabolic crises in TANGO2 patients, such as some anesthetics and possibly l-carnitine. Unexpectedly, plasma acylcarnitines, plasma FGF-21, muscle histology, and mitochondrial spectrometry were mostly normal. Moreover, in patients' primary myoblasts, palmitate and glutamine oxidation rates, and the mitochondrial network were also normal. Finally, we found variable mitochondrial respiration and defective clearance of oxidized DNA upon cycles of starvation and refeeding. We conclude that TANGO2 disease is a life-threatening disease that needs specific cardiac management and anesthesia protocol. Mechanistically, TANGO2 disease is unlikely to originate from a primary mitochondrial defect. Rather, we suggest that mitochondrial defects are secondary to strong extrinsic triggers in TANGO2 deficient patients., (© 2020 SSIEM.)

Introduction: Neuronal Ceroid Lipofuscinosis type 2 (CLN2) is a neurodegenerative lysosomal disease which leads to early dementia and death without treatment. The recently available therapy consists of intracerebroventricular enzyme substitution: cerliponase alfa. In this report, we describe the evolution of the first French children treated with cerliponase alfa., Method: CLN2 Clinical Rating Scale Motor-Language (CLN2 ML) assesses the motor and language evolution of CLN2 patients. We retrospectively studied patients' medical records: clinical symptoms, MRI conclusions, gene mutation, side effects of infusions, patient's age and CLN2 ML scores at diagnosis, at the beginning of enzyme replacement therapy (ERT) and at the last evaluation. Seven patients were included., Results: Average age at diagnosis was 50 months ( ±10) with CLN2 ML score equal to 3.6 [1.5-5]. Average age at the beginning of ERT was 56 months ( ±13) with CLN2 ML score equal to 3.1 [1-5]. At the last available evaluation, average age was 82 months ( ±20) with CLN2 ML score equal to 2.8 [0-5]. Thus, in 26 months, the mean CLN2 ML score only decreased by 0.3 points. However, patients with a CLN2 ML score greater than three at the onset of ERT experienced a stabilisation or improvement of clinical signs, whereas patients with a CLN2 ML score less than three at baseline continue to deteriorate., Conclusion: For patients starting ERT at an early stage of the disease, cerliponase alfa changes the natural history of the disease with a halt in disease progression or even a slight improvement in clinical symptoms., Competing Interests: Declaration of competing interest AC, SP, DS, ID, SA, BC reports grants personal fees from BioMarin independent of the submitted work. All other authors report no competing interests., (Copyright © 2020 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.)

Objective: To describe the health status of young patients affected by inborn errors of metabolism that require adherence to a restricted diet (IEMRDs) and to describe and compare their self- and proxy (parent)-reported quality of life (QoL) with reference values., Study Design: A cross-sectional study was conducted in 2015-2017 in patients affected by IEMRDs (except phenylketonuria) younger than 18 years. Data collection was based on medical records, clinical examinations, parents' and children's interviews, and self-reported questionnaires. Measurements included clinical and healthcare data, child and family environment data, and self- and proxy (parent)-reported QoL., Results: Of the 633 eligible participants, 578 were recruited (50.3% boys; mean age: 8.7 years); their anthropometric status did not differ from the general population. Approximately one-half of them had at least 1 complication of the disease. Their self-reported global QoL did not differ from that of the general population. However, relations with friends and leisure activities QoL domains were negatively impacted, whereas relations with medical staff, relations with parents, and self-esteem QoL domains were positively impacted. Their proxy (parent)-reported QoL was negatively impacted., Conclusions: Young patients affected by IEMRDs present a high rate of clinical complications. Although their proxy (parent)-reported QoL was negatively impacted, their self-reported QoL was variably impacted (both positively and negatively). These results may inform counseling for those who care for affected patients and their families., (Copyright © 2020 Elsevier Inc. All rights reserved.)