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BACKGROUND AND OBJECTIVES: Pathogenic variants in STXBP1 are among the major genetic causes of neurodevelopmental disorders. Despite the increasing number of individuals diagnosed without a history of epilepsy, little is known about the natural history and developmental trajectories in this subgroup and endpoints for future therapeutic studies are limited to seizure control.; METHODS: We performed a cross-sectional retrospective study using standardized questionnaires for clinicians and caregivers of individuals with STXBP1-related disorders capturing medical histories, genetic findings, and developmental outcomes. Motor and language function were assessed using Gross Motor Function Classification System scores (GMFCS) and a speech impairment score and were compared within and across clinically defined subgroups.; RESULTS: We collected data of 71 individuals with STXBP1-related disorders, including 44 previously unreported individuals. Median age at inclusion was 5.3 years (IQR = 3.5-9.3) with the oldest individual aged 43.8 years. Epilepsy was absent in 18/71 (25%) of individuals. The range of developmental outcomes was broad, including two individuals presenting with close to age-appropriate motor development. 29/61 (48%) individuals were able to walk unassisted and 24/69 (35%) were able to speak single words. Individuals without epilepsy presented with a similar onset and spectrum of phenotypic features but had lower GMFCS scores (median 3 vs. 4, p < 0.01) than individuals with epilepsy. Individuals with epileptic spasms were less likely to walk unassisted than individuals with other seizure types (6% vs. 58%, p < 0.01). Individuals with early epilepsy onset had higher speech impairment scores (p = 0.02) than individuals with later epilepsy onset.; DISCUSSION: We expand the spectrum of STXBP1-related disorders and provide clinical features and developmental trajectories in individuals with and without a history of epilepsy. Individuals with epilepsy, in particular epileptic spasms, and neonatal or early-onset, presented with less favorable motor and language functional outcomes compared to individuals without epilepsy. These findings identify children at risk for severe disease and can serve as comparator for future interventional studies in STXBP1-related disorders. © 2023 American Academy of Neurology.

Data de publicació electrònica: 23-03-2022 Background and purpose: The therapeutic landscape of spinal muscular atrophy (SMA) has changed dramatically during the past 4 years, but treatment responses differ remarkably between individuals, and therapeutic decision-making remains challenging, underlining the persistent need for validated biomarkers. Methods: We applied untargeted proteomic analyses to determine biomarkers in cerebrospinal fluid (CSF) samples of SMA patients under treatment with nusinersen. Identified candidate proteins were validated in CSF samples of SMA patients by Western blot and enzyme-linked immunosorbent assay. Furthermore, levels of peripheral neurofilament heavy and light chain were determined. Results: Untargeted proteomic analysis of CSF samples of three SMA type 1 patients revealed the lysosomal protease cathepsin D as a candidate biomarker. Subsequent validation analysis in a larger cohort of 31 pediatric SMA patients (type 1, n = 12; type 2, n = 9; type 3, n = 6; presymptomatically treated, n = 4; age = 0-16 years) revealed a significant decline of cathepsin D levels in SMA patients aged ≥2 months at the start of treatment. Although evident in all older age categories, this decline was only significant in the group of patients who showed a positive motor response. Moreover, downregulation of cathepsin D was evident in muscle biopsies of SMA patients. Conclusions: We identified a decline of cathepsin D levels in CSF samples of SMA patients under nusinersen treatment that was more pronounced in the group of "treatment responders" than in "nonresponders." We believe that our results indicate a suitability of cathepsin D levels as a possible biomarker in SMA also in older patients, in combination with analysis of peripheral neurofilament light chain in adolescents or alone in adult patients. Funding: H.L. receives support from the Canadian Institutes of Health Research (Foundation Grant FDN-167281), the Canadian Institutes of Health Research and Muscular Dystrophy Canada (Network Catalyst Grant for NMD4C), the Canada Foundation for Innovation (CFI-JELF 38412), and the Canada Research Chairs program (Canada Research Chair in Neuromuscular Genomics and Health, 950-232279). This work was also supported by a grant of the French Muscular Dystrophy Association (AFM-Téléthon;#21466) to A.R. The work of B.W. is supported by the German Research Foundation (Wi945/17-1, SFB 1451 [project-ID 431549029–A01] and GRK1960 [project ID 233886668]), the European Research Council under the European Union's Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement 956185 (SMABEYOND), and the Center for Molecular Medicine Cologne (project No C18)

ollaborators: Bloxam S, Brody L, Caspi L, Elsbecker S, Fierro L, Lynn A, Mullins M, Mütze U, Papaleo C, Payan I, Seminara J, Simpson K, Singer R, Wallis K, Alber FD, Babikian T, Bender H, Boys C, Breiger D, Buerger C, Caudle SE, NguyenDriver M, Kerr E, Mamak E, Sanz JH, Tangen R, Wilkening G, Cederbaum S, Feigenbaum A, Kerr DS, LichterKonecki U, Seashore MR, Berry SA, Burrage L, Coughlin C, Diaz GA, Gallagher RC, Gropman A, Harding CO, Lee B, Le Mons C, Lawrence Merritt J 2nd, Nagamani SCS, Schulze A, Stricker T, Tuchman M, Waisbren S, WeisfeldAdams J, Wong D, Yudkoff M, Arnoux J, Bari Cacute I, Bosch AM, Chabrol B, Chakrapani A, CortèsSaladefont E, Couce ML, Eyskens F, de Laet C, de Meirleir L, Freisinger P, Gleich F, Grünewald S, Häberle J, Hwu W, Jalan A, Karall D, Lindner M, Lund AM, Martinelli D, Murphy E, Mühlhausen C, Olivieri G, Ottolenghi C, Rodrigues E, Rubert L, Sarajlija A, Schiff M, Sokal E, SykutCegielska J, Walter JH, Williams M, Zeman J. BACKGROUND: To improve our understanding of urea cycle disorders (UCDs) prospectively followed by two North American (NA) and European (EU) patient cohorts. AIMS: Description of the NA and EU patient samples and investigation of the prospects of combined and comparative analyses for individuals with UCDs. METHODS: Retrieval and comparison of the data from 1095 individuals (NA: 620, EU: 475) from two electronic databases. RESULTS: The proportion of females with ornithine transcarbamylase deficiency (fOTC-D), particularly those being asymptomatic (asfOTC-D), was higher in the NA than in the EU sample. Exclusion of asfOTC-D resulted in similar distributions in both samples. The mean age at first symptoms was higher in NA than in EU patients with late onset (LO), but similar for those with early (≤ 28 days) onset (EO) of symptoms. Also, the mean age at diagnosis and diagnostic delay for EO and LO patients were similar in the NA and EU cohorts. In most patients (including fOTC-D), diagnosis was made after the onset of symptoms (59.9%) or by high-risk family screening (24.7%), and less often by newborn screening (8.9%) and prenatal testing (3.7%). Analysis of clinical phenotypes revealed that EO patients presented with more symptoms than LO individuals, but that numbers of symptoms correlated with plasma ammonium concentrations in EO patients only. Liver transplantation was reported for 90 NA and 25 EU patients. CONCLUSIONS: Combined analysis of databases drawn from distinct populations opens the possibility to increase sample sizes for natural history questions, while comparative analysis utilizing differences in approach to treatment can evaluate therapeutic options and enhance long-term outcome studies.