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Objectives: Precise characterization of cognitive outcomes and factors that contribute to cognitive variability will enable better understanding of disease progression and treatment effects in mucopolysaccharidosis type I (MPS I). We examined the effects on cognition of phenotype, genotype, age at evaluation and first treatment, and somatic disease burden. Methods: Sixty patients with severe MPS IH (Hurler syndrome treated with hematopoietic cell transplant and 29 with attenuated MPS I treated with enzyme replacement therapy), were studied with IQ measures, medical history, genotypes. Sixty-seven patients had volumetric MRI. Subjects were grouped by age and phenotype and MRI and compared to 96 normal controls. Results: Prior to hematopoietic cell transplant, MPS IH patients were all cognitively average, but post-transplant, 59% were below average, but stable. Genotype and age at HCT were associated with cognitive ability. In attenuated MPS I, 40% were below average with genotype and somatic disease burden predicting their cognitive ability. White matter volumes were associated with IQ for controls, but not for MPS I. Gray matter volumes were positively associated with IQ in controls and attenuated MPS I patients, but negatively associated in MPS IH. Conclusions: Cognitive impairment, a major difficulty for many MPS I patients, is associated with genotype, age at treatment and somatic disease burden. IQ association with white matter differed from controls. Many attenuated MPS patients have significant physical and/or cognitive problems and receive insufficient support services. Results provide direction for future clinical trials and better disease management.

Pyruvate dehydrogenase (PDH) deficiency is a major cause of neurological dysfunction and lactic acidosis in infancy and early childhood. The great majority of cases (>80%) result from mutations in the X-linked gene for the E1alpha subunit of the complex (PDHA1). Mutations in the genes for the other subunits have all been described, but only dihydrolipoamide dehydrogenase (E3) and E3 binding protein (E3BP) defects contribute significantly to the total number of patients with PDH deficiency. Although previously considered rare, with only 13 reported cases, we have found that mutations in PDX1, the gene for the E3 binding protein, are in fact relatively common. Clinical, biochemical, and genetic features of six new patients (four males, two females; age range 15mo-6y) with mutations in this gene are compared with previously reported cases. All patients with E3BP deficiency identified to date have mutations which completely prevent synthesis of the protein product. However, they are generally less severely affected than patients with PDHA1 mutations, although there is considerable overlap in clinical and neuroradiological features. [ABSTRACT FROM AUTHOR]

Abstract Background Mucopolysaccharidosis type I (MPS I) is traditionally divided into three phenotypes: the severe Hurler (MPS I-H) phenotype, the intermediate Hurler-Scheie (MPS I-H/S) phenotype and the attenuated Scheie (MPS I-S) phenotype. However, there are no clear criteria for delineating the different phenotypes. Because decisions about optimal treatment (enzyme replacement therapy or hematopoietic stem cell transplantation) need to be made quickly and depend on the presumed phenotype, an assessment of phenotypic severity should be performed soon after diagnosis. Therefore, a numerical severity scale for classifying different MPS I phenotypes at diagnosis based on clinical signs and symptoms was developed. Methods A consensus procedure based on a combined modified Delphi method and a nominal group technique was undertaken. It consisted of two written rounds and a face-to-face meeting. Sixteen MPS I experts participated in the process. The main goal was to identify the most important indicators of phenotypic severity and include these in a numerical severity scale. The correlation between the median subjective expert MPS I rating and the scores derived from this severity scale was used as an indicator of validity. Results Full consensus was reached on six key clinical items for assessing severity: age of onset of signs and symptoms, developmental delay, joint stiffness/arthropathy/contractures, kyphosis, cardiomyopathy and large head/frontal bossing. Due to the remarkably large variability in the expert MPS I assessments, however, a reliable numerical scale could not be constructed. Because of this variability, such a scale would always result in patients whose calculated severity score differed unacceptably from the median expert severity score, which was considered to be the 'gold standard'. Conclusions Although consensus was reached on the six key items for assessing phenotypic severity in MPS I, expert opinion on phenotypic severity at diagnosis proved to be highly variable. This subjectivity emphasizes the need for validated biomarkers and improved genotype-phenotype correlations that can be incorporated into phenotypic severity assessments at diagnosis.

Background: Liver transplantation (LT) normalizes fasting tolerance in glycogen storage disease type (GSD) 1b. However, reported outcomes post-LT with respect to correction of neutropenia, infection risk and growth are varied. Sodium-glucose cotransporter-2 (SGLT2) inhibitors have been recently shown to improve neutropenia in GSD1b patients., Methods: In this single-center retrospective study, we reviewed all children who underwent LT for GSD1b. Neutropenia, dose of granulocyte colony-stimulating factor (G-CSF), unplanned hospital attendance, anthropometrics, graft rejection, survival, and the effects of dapagliflozin were analyzed. Data from protocol biopsies obtained at 1, 5, and 10 years post-LT and immunosuppression levels were collected., Results: Eight children (6 female), all on G-CSF pre-transplant, underwent cadaveric LT for GSD1b at median age 3.6 years (IQR 3.3-5.1) with mean follow-up time of 10.3 years (95% CI 7.5-13.1). Neutrophil count and G-CSF requirement did not improve post-LT. Although a reduction in unplanned hospital attendance due to infection (0.98 [95% CI 0.76-1.26] vs. 0.49 [95% CI 0.41 to 0.57] per person-year, p < 0.01) was observed, gastrointestinal complaints and graft dysfunction accounted for a similar hospitalization burden pre- versus post-LT. Body mass index (BMI) reduced post-LT (Z-score 1.47 [95%CI 0.39-2.23] vs. 0.56 [95% CI -0.74 to 1.45], p = 0.02), with no significant change in height. Although all children and grafts have survived, 75% of recipients developed rejection, despite adequate immunosuppression levels, with two children having been found to have developed significant fibrosis on their 5-year protocol biopsy. Although dapagliflozin allowed cessation of G-CSF, no improvement in neutrophil count was observed. Despite this, a reduction in gastrointestinal and infection-related morbidity was noted following dapagliflozin., Conclusion: Although LT normalizes fasting tolerance in GSD1b and reduces hospital attendance due to infection, morbidity from infection and gastrointestinal manifestations persist. Children in our cohort experienced high rates of rejection necessitating titration of immunosuppression to balance risk of infection against organ rejection. Future studies should investigate whether early introduction of SGLT2 inhibitors post-LT impact morbidity in this group., (© 2024 Wiley Periodicals LLC.)

Background: Niemann-Pick disease type C (NPC) is a rare, fatal, pan-ethnic, autosomal recessive lysosomal storage disease characterized by progressive major organ failure and neurodegeneration. Preclinical studies confirmed a critical role of systemically administered hydroxypropyl-β-cyclodextrin (HP-β-CD; Trappsol ® Cyclo™) in cholesterol metabolism and homeostasis in peripheral tissues of the body, including the liver, and in the central nervous system (CNS). Herein, the pharmacokinetics (PK), safety, and efficacy of HP-β-CD, and biomarkers of NPC were assessed in pediatric and adult patients with NPC1., Methods: This was a multicenter, Phase I/II, randomized, double-blind, parallel-group, 48-week study (ClinicalTrials.gov identifier NCT02912793) to compare the PK of three different single intravenous (IV) doses of HP-β-CD in pediatric and adult patients with NPC1 and to evaluate the efficacy and tolerability of three different dosages of HP-β-CD in patients with NPC1 after long-term treatment. Twelve patients aged at least 2 years (2-39 years of age) with a confirmed diagnosis of NPC1 were randomized to receive one of three IV doses of HP-β-CD (1500 mg/kg, 2000 mg/kg, or 2500 mg/kg) every 2 weeks for 48 weeks. All patients received HP-β-CD; there was no placebo or other control. PK testing of plasma and cerebrospinal fluid (CSF) was at set times after the first infusion. Pharmacodynamic assessments included biomarkers of cholesterol metabolism (synthesis and breakdown products), N -palmitoyl- O -phosphocholineserine (PPCS), and specific biomarkers of CSF neurodegeneration (including total Tau), CNS inflammation (glial fibrillary acidic protein [GFAP] and tumor necrosis factor α [TNFα]), CNS cholesterol metabolism (24S-hydroxycholesterol) and inflammatory markers. Efficacy measures included clinical disease severity, neurologic symptoms, and clinical impressions of improvement. Safety assessment included physical examination, vital signs, clinical safety laboratory assessment and adverse events (AEs)., Results: Nine patients completed the study, 2 in the 1500 mg/kg group, 4 in the 2000 mg/kg group and 3 in the 2500 mg/kg group. Three patients (all in the 1500 mg/kg group) discontinued the study because of either physician decision/site Principal Investigator (PI) discretion, withdrawal by subject/patient/parent/guardian, or other non-safety reasons. In 5 patients who underwent serial lumbar punctures, HP-β-CD was detected in the CSF. Of the 9 patients who completed the study, 8 (88.9%) improved in at least two domains of the 17-Domain Niemann-Pick disease Type C-Clinical Severity Scale (17D-NPC-CSS), and 6 of these patients improved in at least one domain viewed by patients and their caregivers to be key to quality of life, namely, speech, swallow, fine and gross motor skills, and cognition. Of the 9 patients who completed the study, 7 were viewed by their treating physicians as having improved to some degree at the end of the study, and 2 remained stable; both outcomes are highly relevant in a progressive neurodegenerative disease. Some patients and families reported improvement in quality of life.All three doses of HP-β-CD were well tolerated overall, with most treatment-emergent adverse events transient, mild-to-moderate in nature, and considered by the site PIs to be not related to study drug., Interpretation: This 48-week trial is the longest to date to evaluate the safety, tolerability, and efficacy across multiple clinical endpoints of IV administration of Trappsol ® Cyclo™ (HP-β-CD) in NPC1 patients. In pediatric and adult patients with NPC, Trappsol ® Cyclo™ IV improved clinical signs and symptoms and was generally well tolerated. The findings presented here demonstrate a favorable benefit-risk profile and support the global pivotal trial now underway to evaluate the long-term treatment benefits and the potential of Trappsol ® Cyclo™ as a disease-modifying treatment in this patient population., Competing Interests: None., (© 2023 The Author(s).)

Background: The Morquio A Registry Study (MARS) is an ongoing, multinational, observational study of patients with MPS IVA. Key objectives of MARS are to characterize the heterogeneity and natural history of disease and to evaluate long-term effectiveness and safety of elosulfase alfa enzyme replacement therapy (ERT). Enrollment began in September 2014; data on medical history, clinical outcomes, and safety assessments are collected as part of routine care., Results: As of February 2021, 381 subjects from 17 countries had enrolled in MARS: 58 ERT-naïve subjects and 323 ERT-treated subjects (≥1 infusion), with a mean ERT exposure of 5.5 years (SD 2.8) and median age at first ERT treatment of 9.8 years. ERT-treated subjects were younger at diagnosis (median 3.4 vs 6.5 years) relative to ERT-naïve subjects. Among ERT-treated subjects, urinary keratan sulfate (uKS) levels declined from pre-ERT baseline to last follow-up on treatment (mean % change [95% confidence interval]: -52.5% [-57.5%, -47.4%]; n = 115) and 6-min walk test distance remained stable (mean change: -6.1 [-27.6, 15.5] m; n = 131) over a mean follow-up of 5.5 years. Forced expiratory volume in 1 s (FEV 1 ) and forced vital capacity (FVC) increased in subjects who were < 18 years of age at ERT initiation (mean change: +0.3 [0.1, 0.4] L and + 0.4 [0.3, 0.5] L; mean follow-up: ∼6 years; n = 82) and were stable in subjects ≥18 years (mean change: 0.0 [-0.0, 0.1] L and 0.0 [-0.1, 0.1] L; mean follow-up: 4.6 years; n = 38). Overall, 148 (47.1%) ERT-treated subjects experienced ≥1 adverse event (AE) and 110 subjects (35%) reported ≥1 serious AE. Drug-related AEs were reported in 39 (12.4%) subjects; the most common were hypersensitivity (9 subjects [2.9%]), urticaria (8 subjects [2.5%]), and pyrexia (7 subjects [2.2%])., Conclusions: MARS is the longest and largest observational study of MPS IVA patients to date, with a heterogenous population that is representative of the MPS IVA population overall. Data collected over the first 6 years of MARS provide real-world evidence for long-term stabilization of endurance and respiratory function among ERT-treated patients, with no new safety concerns identified., Competing Interests: Declaration of Competing Interest JM reports advisory boards for BioMarin, Genzyme, Takeda, and Ultragenyx, consulting fees from BioMarin, Genzyme, Takeda, and Ultragenyx, contracted research for BioMarin, Genzyme, RegenxBio, and Takeda, honoraria from BioMarin and Genzyme and speaker's bureau for BioMarin. BKB reports consulting fees from Aeglea, BioMarin, Denali, Horizon, JCR Pharma, Moderna, Shire (Takeda), SIO, and Ultragenyx, contracted research for BioMarin, Denali, Homology Medicines, Sangamo, Shire (Takeda), and Ultragenyx, and speaker's bureau for BioMarin, Horizon, and Shire (Takeda). MBB reports advisory boards, consulting fees, and contracted research for BioMarin, and contracted research for RegenxBio. PMC reports consulting fees from BioMarin and Genzyme, and contracted research for BioMarin, Genzyme, and Takeda. CE reports advisory boards for Amicus, BioMarin, Chiesi, and Sanofi Genzyme, consulting fees from BioMarin and Sanofi Genzyme, honoraria from BioMarin, Sanofi Genzyme, and Takeda Shire, speaker's bureau for Amicus, BioMarin, Sanofi Genzyme, and Takeda Shire, and travel expenses from Amicus, BioMarin, Sanofi Genzyme, and Takeda Shire. KB has no conflicts of interest. NG reports advisory boards for BioMarin, Chiesi, Sanofi Genzyme, Takeda Shire HGT, and Ultragenyx, consulting fees from Sanofi Genzyme, and Ultragenyx, contracted research for BioMarin, Chiesi, Sanofi Genzyme, Shire HGT, and Ultragenyx, and travel expenses from Sanofi Genzyme, and Ultragenyx. SL reports advisory boards for BioMarin. MM reports advisory board for BioMarin and speaker's honoraria from BioMarin, Chiesi, and Takeda. JR reports advisory boards for BioMarin, Sanofi, and Takeda. Honoraria from BioMarin, Sanofi, and Takeda, and travel expenses from BioMarin, Sanofi, and Takeda. KMS reports advisory boards for BioMarin, Chiesi, Orchard Therapeutics, Sanofi, and Takeda, and honoraria from BioMarin, Orchard Therapeutics, Sanofi, and Takeda, SC, SD, DH, and AL are employees of BioMarin. LS-S was an employee of BioMarin at the time of submission of the manuscript., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Mitochondria are epicentres of eukaryotic metabolism and bioenergetics. Pioneering efforts in recent decades have established the core protein componentry of these organelles 1 and have linked their dysfunction to more than 150 distinct disorders 2,3 . Still, hundreds of mitochondrial proteins lack clear functions 4 , and the underlying genetic basis for approximately 40% of mitochondrial disorders remains unresolved 5 . Here, to establish a more complete functional compendium of human mitochondrial proteins, we profiled more than 200 CRISPR-mediated HAP1 cell knockout lines using mass spectrometry-based multiomics analyses. This effort generated approximately 8.3 million distinct biomolecule measurements, providing a deep survey of the cellular responses to mitochondrial perturbations and laying a foundation for mechanistic investigations into protein function. Guided by these data, we discovered that PIGY upstream open reading frame (PYURF) is an S-adenosylmethionine-dependent methyltransferase chaperone that supports both complex I assembly and coenzyme Q biosynthesis and is disrupted in a previously unresolved multisystemic mitochondrial disorder. We further linked the putative zinc transporter SLC30A9 to mitochondrial ribosomes and OxPhos integrity and established RAB5IF as the second gene harbouring pathogenic variants that cause cerebrofaciothoracic dysplasia. Our data, which can be explored through the interactive online MITOMICS.app resource, suggest biological roles for many other orphan mitochondrial proteins that still lack robust functional characterization and define a rich cell signature of mitochondrial dysfunction that can support the genetic diagnosis of mitochondrial diseases., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

Objective: To assess our hypothesis that brain macrostructure is different in individuals with mucopolysaccharidosis type I (MPS I) and healthy controls (HC), we conducted a comprehensive multicenter study using a uniform quantitative magnetic resonance imaging (qMRI) protocol, with analyses that account for the effects of disease phenotype, age, and cognition., Methods: Brain MRIs in 23 individuals with attenuated (MPS IA) and 38 with severe MPS I (MPS IH), aged 4-25 years, enrolled under the study protocol NCT01870375, were compared to 98 healthy controls., Results: Cortical and subcortical gray matter, white matter, corpus callosum, ventricular and choroid plexus volumes in MPS I significantly differed from HC. Thicker cortex, lower white matter and corpus callosum volumes were already present at the youngest MPS I participants aged 4-5 years. Age-related differences were observed in both MPS I groups, but most markedly in MPS IH, particularly in cortical gray matter metrics. IQ scores were inversely associated with ventricular volume in both MPS I groups and were positively associated with cortical thickness only in MPS IA., Conclusions: Quantitatively-derived MRI measures distinguished MPS I participants from HC as well as severe from attenuated forms. Age-related neurodevelopmental trajectories in both MPS I forms differed from HC. The extent to which brain structure is altered by disease, potentially spared by treatment, and how it relates to neurocognitive dysfunction needs further exploration., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Biallelic loss-of-function NDUFA12 variants have hitherto been linked to mitochondrial complex I deficiency presenting with heterogeneous clinical and radiological features in nine cases only., Objectives: To fully characterize, both phenotypically and genotypically, NDUFA12 -related mitochondrial disease., Methods: We collected data from cases identified by screening genetic databases of several laboratories worldwide and systematically reviewed the literature., Results: Nine unreported NDUFA12 cases from six pedigrees were identified, with presentation ranging from movement disorder phenotypes (dystonia and/or spasticity) to isolated optic atrophy. MRI showed basal ganglia abnormalities ( n  = 6), optic atrophy ( n  = 2), or was unremarkable ( n  = 1). All carried homozygous truncating NDUFA12 variants, three of which are novel., Conclusions: Our case series expands phenotype-genotype correlations in NDUFA12 -associated mitochondrial disease, providing evidence of intra- and inter-familial clinical heterogeneity for the same variant. It confirms NDUFA12 variants should be included in the diagnostic workup of Leigh/Leigh-like syndromes - particularly with dystonia - as well as isolated optic atrophy., Competing Interests: Biological samples from pedigree C were collected as part of the SYNaPS Study Group collaboration funded by The Wellcome Trust and strategic award (Synaptopathies) funding (WT093205 MA and WT104033AIA) and research was conducted as part of the Queen Square Genomics group at University College London, supported by the National Institute for Health Research University College London Hospitals Biomedical Research Centre. Biological samples from pedigree D were collected as part of the project RAC# 2121053. Francesca Magrinelli is supported by the Edmond J. Safra Foundation and by the research grant “Fondo Gianesini” in collaboration with UniCredit Foundation and University of Verona, Italy. Robert W. Taylor is supported by the Wellcome Centre for Mitochondrial Research (203,105/Z/16/Z), the MRC International Centre for Genomic Medicine in Neuromuscular Disease (MR/S005021/1), Mitochondrial Disease Patient Cohort (UK) (G0800674), the UK NIHR Biomedical Research Centre for Aging and Age‐related disease award to the Newcastle upon Tyne Foundation Hospitals NHS Trust, The Lily Foundation, the Pathology Society and the UK NHS Highly Specialized Service for Rare Mitochondrial Disorders of Adults and Children. Kailash P. Bhatia has received grant support from Wellcome/MRC, NIHR, Parkinson's UK and EU Horizon 2020. Tobias B. Haack was supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)—418081722, 433158657. Kate Sargeant thanks the UK NHS Specialist Commissioners, which funds the “Rare Mitochondrial Disease Service for Adults and Children” in Oxford for their support. The views expressed are those of the author(s) and not necessarily those of the NHS or the UK Department of Health and Social Care. Rita Horvath is a Wellcome Trust Investigator (109,915/Z/15/Z), who receives support from the Medical Research Council (UK) (MR/N025431/1 and MR/V009346/1), the European Research Council (309548), the Newton Fund (UK/Turkey, MR/N027302/1), the Addenbrookes Charitable Trust (G100142), the Evelyn Trust, the Stoneygate Trust, the Lily Foundation and an MRC strategic award to establish an International Centre for Genomic Medicine in Neuromuscular Diseases (ICGNMD) MR/S005021/1. This research was supported by the NIHR Cambridge Biomedical Research Centre (BRC‐1215‐20,014). The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care. Henry Houlden is funded by The MRC (MR/S01165X/1, MR/S005021/1, G0601943), The National Institute for Health Research University College London Hospitals Biomedical Research Centre, Rosetree Trust, Ataxia UK, MSA Trust, Brain Research UK, Sparks GOSH Charity, Muscular Dystrophy UK (MDUK), Muscular Dystrophy Association (MDA USA). The authors declare that there are no conflicts of interest relevant to this work., (© 2021 The Authors. Movement Disorders Clinical Practice published by Wiley Periodicals LLC. on behalf of International Parkinson and Movement Disorder Society.)

Background: To report on clinical presentation and outcomes of children who underwent liver transplantation (LTx) and were subsequently diagnosed to have Niemann-Pick type C (NPC)., Methods: Retrospective, descriptive, multi-centre review of children diagnosed with NPC who underwent LTx (2003-2018). Diagnosis was made by filipin skin test or genetic testing., Results: Nine children were identified (six centres). Neonatal acute liver failure was the most common indication for LTx (seven children). Median age at first presentation: 7 days (range: 0-37). The most prevalent presenting symptoms: jaundice (8/9), hepatosplenomegaly (8/9) and ascites (6/9). 8/9 children had a LTx before the diagnosis of NPC. Genetic testing revealed mutations in NPC1 correlating with a severe biochemical phenotype in 5 patients. All 9 children survived beyond early infancy. Seven children are still alive (median follow-up time of 9 (range: 6-13) years). Neurological symptoms developed in 4/7 (57%) patients at median 9 (range: 5-13) years following LTx., Conclusion: Early diagnosis of NPC continues to be a challenge and a definitive diagnosis is often made only after LTx. Neurological disease is not prevented in the majority of patients. Genotype does not appear to predict neurological outcome after LTx. LTx still remains controversial in NPC.

Introduction: Musculoskeletal findings in MPS can progress after enzyme replacement. Our aim was to examine synovial recesses, tendons, retinacula and pulleys using ultrasonography for structural and inflammatory changes., Material and Methods: The wrist, metacarpophalangeal (MCP), proximal and distal interphalangeal (PIP and DIP) joints, the finger flexor tendons and the knee including entheses of quadriceps and patella tendons were assessed clinically. Ultrasonography of the various synovial recesses of the wrist as well as the extensor retinaculum, carpal tunnel, MCP, PIP and DIP joints of the second finger, extensor and flexor tendons, A1-5 pulleys and the knee joint including relevant entheses followed. Significance of differences between patient values and available normative data were assessed using t-tests., Results: Ultrasonography showed significant abnormal intraarticular material in the wrist without a clear distribution to synovial recesses and without effusions. Doppler signals were found in a perisynovial distribution and not intrasynovial as expected in in inflammatory arthritis. Findings were similar in the knee but not the fingers. Flexor and extensor tendons were also mostly normal in their structure but significant thickening of retinaculae and the flexor tendon pulleys was seen (p<0.0001 compared to normal)., Conclusion: MPS I patients showed intraarticular deposition of abnormal material in the wrist and knee but not in the finger joints where significant thickening of retinaculae/pulleys controlling tendon position was dominant. No ultrasound findings of inflammatory pathology were demonstrated but rather a secondary reaction to abnormal deposition and direct damage of GAG., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Biallelic variants in MMACHC results in the combined methylmalonic aciduria and homocystinuria, called cobalamin (cbl) C (cblC) deficiency. We report 26 patients with cblC deficiency with their phenotypes, genotypes, biochemical parameters, and treatment outcomes, who were diagnosed and treated at our center. We divided all cblC patients into two groups: group 1: SX group: identified after manifestations of symptoms (n = 11) and group 2: NB group: identified during the asymptomatic period via newborn screening (NBS) or positive family history of cblC deficiency (n = 15). All patients in the SX group had global developmental delay and/or cognitive dysfunction at the time of the diagnosis and at the last assessment. Seizure, stroke, retinopathy, anemia, cerebral atrophy, and thin corpus callosum in brain magnetic resonance imaging (MRI) were common in patients in the SX group. Global developmental delay and cognitive dysfunction was present in nine patients in the NB group at the last assessment. Retinopathy, anemia, and cerebral atrophy and thin corpus callosum in brain MRI were less frequent. We report favorable outcomes in patients identified in the neonatal period and treated pre-symptomatically. Identification of cblC deficiency by NBS is crucial to improve neurodevelopmental outcomes., Competing Interests: Danielle K. Bourque, Lizbeth E. Mellin‐Sanchez, Garrett Bullivant, Vivian Cruz, Anette Feigenbaum, Stacy Hewson, Julian Raiman, Andreas Schulze, Komudi Siriwardena, Saadet Mercimek‐Andrews declare that they have no conflict of interest., (© 2020 The Authors. Journal of Inherited Metabolic Disease published by John Wiley & Sons Ltd on behalf of SSIEM.)

Objective: Previous research suggests attention and white matter (WM) abnormalities in individuals with mucopolysaccharidosis type I (MPS I); this cross-sectional comparison is one of the first to examine the relationship of WM structural abnormalities as measured by corpus callosum (CC) volumes with attention scores to evaluate this relationship in a larger sample of patients with MPS I., Methods: Volumetric MRI data and performance on a computerized measure of sustained attention were compared for 18 participants with the severe form of MPS I (MPS IH), 18 participants with the attenuated form of MPS I (MPS I ATT ), and 60 typically developing age-matched controls., Results: The MPS I groups showed below-average mean attention scores ( p < 0.001) and smaller CC volumes ( p < 0.001) than controls. No significant associations were found between attention performance and CC volume for controls. Attention was associated with posterior CC volumes in the participants with MPS IH ( p = 0.053) and total ( p = 0.007) and anterior ( p < 0.001) CC volumes in participants with MPS I ATT ., Conclusions: We found that attention and CC volumes were reduced in participants with MPS I compared to typically developing controls. Smaller CC volumes in participants with MPS I were associated with decreased attention; such an association was not seen in controls. While hematopoietic cell transplantation used to treat MPS IH may compound these effects, attention difficulties were also seen in the MPS I ATT group, suggesting that disease effects contribute substantially to the clinical attentional difficulties seen in this population., (© 2019 American Academy of Neurology.)

We report the outcome of 12 patients with inherited neurotransmitter disorders of monoamine, tetrahydrobiopterin and γ amino butyric acid metabolisms from a single Inherited Neurotransmitter Disorder Clinic including tyrosine hydroxylase (n=2), aromatic l-amino acid decarboxylase (n=1), 6-pyruvoyltetrahydropterin synthase, dihydropteridine reductase and succinic semialdehyde dehydrogenase deficiencies. Six patients (with 6-pyruvoyltetrahydropterin synthase, dihydropteridine reductase and tyrosine hydroxylase deficiencies) had normal neurodevelopmental outcome on treatment. Tetrahydrobiopterin loading test in newborns with positive newborn screening for phenylketonuria will identify patients with 6-pyruvoyltetrahydropterin synthase and dihydropteridine reductase deficiencies resulting in abnormal neurotransmitter synthesis in the central nervous system in the neonatal period to initiate disease-specific treatment to improve neurodevelopmental outcome.

Background: Long-term safety and efficacy of elosulfase alfa enzyme replacement therapy (ERT) were assessed in 173 patients with Morquio A syndrome (mucopolysaccharidosis IVA) in a 96-week, open-label, multi-center, phase 3 extension study (MOR-005) of the pivotal 24-week, placebo-controlled study (MOR-004). Changes in efficacy endpoints were evaluated over 120weeks, from MOR-004 baseline to MOR-005 week 96. We report the impact of ERT on activities of daily living (ADL) across three domains (mobility, self-care, and caregiver-assistance), as assessed by the Mucopolysaccharidosis Health Assessment Questionnaire (MPS-HAQ) after 72 and 120weeks or approximately 1 and 2years., Results: Mean baseline MPS-HAQ domain scores showed impairments in mobility, self-care, and independence. The MOR-005 intent-to-treat population (ITT; N=169, including 158 with 2years follow-up) showed sustained significant reductions (representing improvements) in mobility and self-care domain least square (LS) mean scores vs. baseline at 1 and 2years and a non-significant decrease in the caregiver-assistance domain at 2years. At week 120, LS mean (SE) changes from baseline were -0.5 (0.1) for mobility (P=0.002), -0.4 (0.1) for self-care (P=0.001), and -1.0 (0.5) for caregiver-assistance (P=0.06) (ITT population). Improvements in MPS-HAQ domain scores vs. baseline at 1 and 2years were greater in patients continuously treated with the weekly dosing regimen than in the total MOR-005 population and statistically significant across domains. A comparable untreated cohort of patients from the Morquio A Clinical Assessment Program (MorCAP) natural history study (ITT population, N=94, including 37 with 2years follow-up) showed no improvement over 2years, with two of the three domains worsening (LS mean (SE) changes from baseline: 0.3 (0.3) for mobility, 0.4 (0.2) for self-care, -0.5 (0.8) for caregiver-assistance). Changes in LS mean scores vs. baseline were statistically significantly different between MOR-005 and MorCAP for the mobility domain (-0.7 (SE 0.4), P=0.0490) and the self-care domain (-0.7 (SE 0.3), P=0.0146) at 2years., Conclusions: Together, these findings suggest that long-term elosulfase alfa ERT is associated with partial recovery of functional abilities, improving Morquio A patients' abilities to perform ADL., Trial Registration: ClinicalTrials.govNCT01415427. Registered 8 August 2011, retrospectively registered., (Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: X-linked adrenoleukodystrophy (X-ALD) is a peroxisomal disorder associated with leukodystrophy, myeloneuropathy and adrenocortical insufficiency. We performed a retrospective cohort study to evaluate long-term outcome of patients with X-ALD., Method: All patients with X-ALD diagnosed between 1989 and 2012 were included. Electronic patient charts were reviewed for clinical features, biochemical investigations, molecular genetic testing, neuroimaging, long-term outcome and treatment., Results: Forty-eight patients from 18 unrelated families were included (15 females; 33 males). Seventeen patients were symptomatic at the time of the biochemical diagnosis including 14 with neurocognitive dysfunction and 3 with Addison disease only. Thirty-one asymptomatic individuals were identified by positive family history of X-ALD. During follow-up, eight individuals developed childhood cerebral X-ALD (CCALD), one individual developed adrenomyeloneuropathy (AMN), six individuals developed Addison disease only, and five individuals remained asymptomatic. Direct sequencing of ABCD1 confirmed the genetic diagnosis in 29 individuals. Seven patients with CCALD underwent hematopoietic stem cell transplantation (HSCT). Nine patients lost the follow-up. There was no correlation between clinical severity score, Loes score and elevated degree of elevated very long chain fatty acid (VLCFA) levels in CCALD., Conclusion: Our study reports forty-eight new patients with X-ALD and their long-term outcome. Only 35% of the patients presented with neurological features or Addison disease. The remaining individuals were identified due to positive family history. Close monitoring of asymptomatic males resulted in early HSCT to prevent progressive lethal neurodegenerative disease. Identification of patients with X-ALD is important to improve neurodevelopmental outcome of asymptomatic males., (Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.)

Background: Congenital disorders of glycosylation (CDG) are inborn defects of glycan metabolism. They are multisystem disorders. Analysis of transferrin isoforms is applied as a screening test for CDG type I (CDG-I) and type II (CDG-II). We performed a retrospective cohort study to determine spectrum of phenotype and genotype and prevalence of the different subtypes of CDG-I and CDG-II., Material and Methods: All patients with CDG-I and CDG-II evaluated in our institution's Metabolic Genetics Clinics were included. Electronic and paper patient charts were reviewed. We set-up a high performance liquid chromatography transferrin isoelectric focusing (TIEF) method to measure transferrin isoforms in our Institution. We reviewed the literature for the rare CDG-I and CDG-II subtypes seen in our Institution., Results: Fifteen patients were included: 9 with PMM2-CDG and 6 with non-PMM2-CDG (one ALG3-CDG, one ALG9-CDG, two ALG11-CDG, one MPDU1-CDG and one ATP6V0A2-CDG). All patients with PMM2-CDG and 5 patients with non-PMM2-CDG showed abnormal TIEF suggestive of CDG-I or CDG-II pattern. In all patients, molecular diagnosis was confirmed either by single gene testing, targeted next generation sequencing for CDG genes, or by whole exome sequencing., Conclusion: We report 15 new patients with CDG-I and CDG-II. Whole exome sequencing will likely identify more patients with normal TIEF and expand the phenotypic spectrum of CDG-I and CDG-II., (Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.)

Objective: To present long-term respiratory function outcomes from an open-label, multi-center, phase 3 extension study (MOR-005) of elosulfase alfa enzyme replacement therapy (ERT) in patients with Morquio A syndrome., Methods: In part 1 of MOR-005, patients initially randomized to ERT in the 24-week pivotal study (MOR-004) remained on their regimen (2.0 mg/kg/week or every other week); placebo patients were re-randomized to one of the two regimens. During part 2, all patients received elosulfase alfa 2.0 mg/kg/week. Respiratory function was one of the efficacy endpoints evaluated in MOR-005. Change from MOR-004 baseline to 120 weeks of treatment for the combined population was determined and compared with results from untreated patients from a Morquio A natural history study (MorCAP)., Results: Maximum voluntary ventilation (MVV) improved up to week 72 and then stabilized; forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV 1 ) increased continuously over 120 weeks. Mean increases in the modified per-protocol population was 9.2 % for FVC, 8.8 % for FEV 1 , and 6.1 % for MVV after 120 weeks. All patients ≤14 years showed respiratory improvements, presumably in part related to growth; however, these were greater in treated patients. For those >14 years, treated patients showed improvements, while deterioration occurred in untreated. Altogether, the improvements were significantly greater (P < 0.05) in treated patients., Conclusions: Long-term ERT is associated with sustained improvements in respiratory function in Morquio A. In younger patients (≤14 years), some improvement may be ascribed to growth. In older patients, other mechanisms, e.g., decreased glycosaminoglycan storage, are likely involved., Competing Interests: Compliance with ethics standards Competing interest C J Hendriksz has received consulting fees and travel support from BioMarin Pharmaceutical Inc., Alexion, Actelion, Amicus, Genzyme, and Shire; K I Berger has received consulting fees from BioMarin Pharmaceutical Inc., Teva, Vertex, Sarepta and Genzyme; R Parini has received travel grants and honoraria for scientific presentations or advisory boards from BioMarin Pharmaceutical Inc., Shire and Genzyme; M AlSayed has received honorarium and travel reimbursement from BioMarin Pharmaceutical Inc., Shire, and Genzyme; J Raiman has received travel support and speakers fees from BioMarin, Shire, Genzyme and Actelion; R Giugliani has received investigator fees, travel grants, and speaker honoraria from BioMarin Pharmaceutical, Inc.; J J Mitchell has received consulting fees and travel reimbursement from BioMarin Pharmaceutical Inc. and Genzyme and honoraria from BioMarin Pharmaceutical Inc. and Shire; B K Burton has received royalties from McGraw-Hill and clinical trial funding, consulting fees and/or honoraria from BioMarin Pharmaceutical Inc., Shire, Genzyme, Horizon Pharma, Alexion, ReGenX Bio, Armagen, and Cytonet; N Guelbert has received honorarium and travel reimbursement from Biomarin Pharmaceutical Inc., Shire and Genzyme; F Stewart has received honorarium and travel reimbursement from BioMarin Pharmaceutical Inc., Shire, and Genzyme; D A Hughes has received travel grants and honoraria for advisory boards from BioMarin Pharmaceutical Inc.; R Matousek, E Jurecki, and C Decker are employees of BioMarin Pharmaceutical Inc.; P R Harmatz has provided consulting support to BioMarin Pharmaceutical Inc., received research grants, participated in advisory panels, and received speaker honorarium from BioMarin Pharmaceutical Inc. He has also received clinical trial funding, consulting fees and/or honoraria from Armagen, Shire, Genzyme, Enobia (now Alexion), ReGenX Bio, Ciesi, PTC, and Inventiva. Details of funding This study and support in the process of manuscript development were funded by BioMarin Pharmaceutical Inc. The site in Monza (Dr. Parini) received continuous economical support to the clinical work of the Center from Fondazione Pierfranco and Luisa Mariani. This publication was supported in part (Dr. Harmatz) by the National Center for Advancing Translational Sciences, National Institutes of Health (NIH), through UCSF-CTSI Grant Number UL1 TR000004. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIH.

Mucopolysaccharidoses (MPSs) are a group of disorders resulting from primary defects in lysosomal enzymes involved in the degradation of glycosaminoglycans (GAGs). Depending on the specific enzyme defect, the catabolism of one or more GAGs is blocked leading to accumulation in tissues and biological fluids. GAG measurements are important for high-risk screening, diagnosis, monitoring treatment efficacy, and patient follow up. The dimethylmethylene blue (DMB) spectrophotometric method commonly used in most biochemical genetics laboratories relies on a non-specific total GAG analysis which has led to false positive results, and even false negative results (mainly for MPS III and IV patients). The main objective of our project was to devise and validate a reliable tandem mass spectrometry multiplex analysis for the urine quantitation of four GAGs (dermatan sulfate (DS), heparan sulfate (HS), keratan sulfate (KS), and chondroitin sulfate (CS)) for an eventual technological transfer to the clinic. The developed methodology is rapid (7 min) and our results showed good intraday and interday precision (RSDs ≤ 8.7%) and accuracy (Biases range: -12.0%-18.4%). Linearity was good (r(2) > 0.995) for DS, HS, CS, and KS calibration curves. In comparison with the DMB spectrophotometric method, this multiplex tandem mass spectrometry method allows GAG fractionation, thus a differentiation of MPS types, except for MPS I and II which are characterized by the same GAG profile. The devised method is a useful and reliable tool for diagnosis of MPS patients, as well as their monitoring and follow up, as shown by longitudinal studies., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Long-term efficacy and safety of elosulfase alfa enzyme replacement therapy were evaluated in Morquio A patients over 96weeks (reaching 120weeks in total from pre-treatment baseline) in an open-label, multi-center, phase III extension study. During this extension of a 24-week placebo-controlled phase III study, all patients initially received 2.0mg/kg elosulfase alfa either weekly or every other week, prior to establishment of 2.0mg/kg/week as the recommended dose, at which point all patients received weekly treatment. Efficacy measures were compared to baseline of the initial 24-week study, enabling analyses of changes over 120weeks. In addition to performing analyses for the entire intent-to-treat (ITT) population (N=173), analyses were also performed for a modified per-protocol (MPP) population (N=124), which excluded patients who had orthopedic surgery during the extension study or were non-compliant with the study protocol (as determined by ≥20% missed infusions). Six-minute walk test (6MWT) was the primary efficacy measure; three-minute stair climb test (3MSCT) and normalized urine keratan sulfate (uKS) were secondary efficacy measures. Mean (SE) change from baseline to Week 120 in 6MWT distance was 32.0 (11.3)m and 39.9 (10.1)m for patients receiving elosulfase alfa at 2.0mg/kg/week throughout the study (N=56) and 15.1 (7.1)m and 31.7 (6.8)m in all patients combined, regardless of dosing regimen, for the ITT and MPP populations, respectively. Further analyses revealed that durability of 6MWT improvements was not impacted by baseline 6MWT distance, use of a walking aid, or age. Mean (SE) change at Week 120 in the 3MSCT was 5.5 (1.9) and 6.7 (2.0)stairs/min for patients receiving elosulfase alfa at 2.0mg/kg/week throughout the study and 4.3 (1.2) and 6.8 (1.3)stairs/min in all patients combined, regardless of dosing regimen, for the ITT and MPP populations, respectively Across all patients, mean (SE) change at Week 120 in normalized uKS was -59.4 (1.8)% and -62.3 (1.8)% in the ITT and MPP populations, respectively. In the absence of a placebo group, significance of the sustained improvements could not be evaluated directly. However, to provide context for interpretation of results, comparisons were performed with untreated patients from a Morquio A natural history study. In contrast to the results of the extension study, the untreated patients experienced constant uKS levels and a gradual decline in endurance test results over a similar period of time. Differences from the untreated natural history study patients were significant for 6MWT, 3MSCT, and uKS outcomes for the cohort of patients receiving optimal dosing throughout the study and for all cohorts pooled together, for both ITT and MPP populations (P<0.05). Safety findings were consistent with those of the initial 24-week study, with no new safety signals identified., (Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.)

Pompe disease is a lysosomal storage disorder caused by a deficiency of the enzyme acid alpha-glucosidase. Patients have skeletal muscle and respiratory weakness with or without cardiomyopathy. The objective of our review was to systematically evaluate the quality of evidence from the literature to formulate evidence-based guidelines for the diagnosis and management of patients with Pompe disease. The literature review was conducted using published literature, clinical trials, cohort studies and systematic reviews. Cardinal treatment decisions produced seven management guidelines and were assigned a GRADE classification based on the quality of evidence in the published literature. In addition, six recommendations were made based on best clinical practices but with insufficient data to form a guideline. Studying outcomes in rare diseases is challenging due to the small number of patients, but this is in particular the reason why we believe that informed treatment decisions need to consider the quality of the evidence.