Key PointsQuestionWhat is the difference in clinical outcomes among 3 corticosteroid regimens (0.75 mg/kg of daily prednisone, 0.90 mg/kg of daily deflazacort, or 0.75 mg/kg of intermittent prednisone for 10 days on and then 10 days off) as initial treatment for boys with Duchenne muscular dystrophy?FindingsThis randomized clinical trial included 196 boys with Duchenne muscular dystrophy; the clinical outcome was a global outcome that incorporated a measure of rising from the floor, forced vital capacity, and global satisfaction with treatment assessed over 3 years. Daily prednisone and daily deflazacort resulted in significantly better outcomes compared with intermittent prednisone; there was no significant difference between the 2 daily regimens.MeaningThe findings support the use of a daily corticosteroid regimen over an intermittent prednisone regimen that alternates dosing for 10 days on and 10 days off as initial treatment for boys with Duchenne muscular dystrophy.

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Intellectual disability (ID) has an estimated prevalence of 1.5%–2%. Whole exome sequencing (WES) studies have identified a multitude of novel causative gene defects and have shown that sporadic ID cases result from de novo mutations in genes associated with ID. Here, we report on a 10‐year‐old girl, who has been regularly presented in our neuropediatric and genetic outpatient clinic. A median cleft palate and a heart defect were surgically corrected in infancy. Apart from ID, she has behavioral anomalies, muscular hypotonia, scoliosis, and hypermobile joints. The facial phenotype is characterized by arched eyebrows, mildly upslanting long palpebral fissures, prominent nasal tip, and large, protruding ears. Trio WES revealed a de novo missense variant in MEIS2 (c.998G>A; p.Arg333Lys). Haploinsufficiency of MEIS2 had been discussed as the most likely mechanism of the microdeletion 5q14‐associated complex phenotype with ID, cleft palate, and heart defect. Recently, four studies including in total 17 individuals with intragenic MEIS2 variants were reported. Here we present the evolution of the clinical phenotype and compare with the data of known individuals.

Background The elucidation of pathomechanisms leading to the manifestation of rare (genetically caused) neurological diseases including neuromuscular diseases (NMD) represents an important step toward the understanding of the genesis of the respective disease and might help to define starting points for (new) therapeutic intervention concepts. However, these “discovery studies” are often limited by the availability of human biomaterial. Moreover, given that results of next-generation-sequencing approaches frequently result in the identification of ambiguous variants, testing of their pathogenicity is crucial but also depending on patient-derived material. Methods Human skin fibroblasts were used to generate a spectral library using pH8-fractionation of followed by nano LC-MS/MS. Afterwards, Allgrove-patient derived fibroblasts were subjected to a data independent acquisition approach. In addition, proteomic signature of an enriched nuclear protein fraction was studied. Proteomic findings were confirmed by immunofluorescence in a muscle biopsy derived from the same patient and cellular lipid homeostasis in the cause of Allgrove syndrome was analysed by fluorescence (BODIPY-staining) and coherent anti-Stokes Raman scattering (CARS) microscopy. Results To systematically address the question if human skin fibroblasts might serve as valuable biomaterial for (molecular) studies of NMD, we generated a protein library cataloguing 8280 proteins including a variety of such linked to genetic forms of motoneuron diseases, congenital myasthenic syndromes, neuropathies and muscle disorders. In silico-based pathway analyses revealed expression of a diversity of proteins involved in muscle contraction and such decisive for neuronal function and maintenance suggesting the suitability of human skin fibroblasts to study the etiology of NMD. Based on these findings, next we aimed to further demonstrate the suitability of this in vitro model to study NMD by a use case: the proteomic signature of fibroblasts derived from an Allgrove-patient was studied. Dysregulation of paradigmatic proteins could be confirmed in muscle biopsy of the patient and protein-functions could be linked to neurological symptoms known for this disease. Moreover, proteomic investigation of nuclear protein composition allowed the identification of protein-dysregulations according with structural perturbations observed in the muscle biopsy. BODIPY-staining on fibroblasts and CARS microscopy on muscle biopsy suggest altered lipid storage as part of the underlying disease etiology. Conclusions Our combined data reveal that human fibroblasts may serve as an in vitro system to study the molecular etiology of rare neurological diseases exemplified on Allgrove syndrome in an unbiased fashion.

Objective:To characterize the spectrum of clinical features in a cohort of X-linked myotubular myopathy (XL-MTM) carriers, including prevalence, genetic features, clinical symptoms and signs, as well as associated disease burden.Methods:We performed a cross-sectional online questionnaire study among XL-MTM carriers. Participants were recruited from patient associations, medical centers and registries in the United Kingdom, Germany and the Netherlands. We used a custom-made questionnaire, the Checklist Individual Strength (CIS), the Frenchay Activities Index (FAI), the SF-12 Health survey and the McGill Pain Questionnaire (MPQ). Carriers were classified as manifesting or non-manifesting, based on self-reported ambulation and muscle weakness.Results:The prevalence of manifesting carriers in this study population (n=76) was 51%, subdivided into mild (independent ambulation, 39%), moderate (assisted ambulation, 9%) and severe (wheelchair-dependent, 3%) phenotypes. In addition to muscle weakness, manifesting carriers frequently reported fatigue (70%) and exercise intolerance (49%). Manifesting carriers scored higher on the overall CIS (p = 0.001), the fatigue sub-scale (p < 0.001) and least severe pain sub-scale (p = 0.005) than non-manifesting carriers. They scored lower on the FAI (p = 0.005) and the physical component of the SF-12 Health survey (p < 0.001).Conclusions:The prevalence of manifesting XL-MTM carriers may be higher than currently assumed, most having a mild phenotype and a wide variety of symptoms. Manifesting carriers are particularly affected by fatigue, limitations of daily activities, pain and reduced quality of life. Our findings should increase awareness and provide useful information for health care providers and future clinical trials.