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Todd JJ, Lawal TA, Witherspoon JW, Chrismer IC, Razaqyar MS, Punjabi M, Elliott JS, Tounkara F, Kuo A, Shelton MO, Allen C, Cosgrove MM, Linton M, Michael D, Jain MS, Waite M, Drinkard B, Wakim PG, Dowling JJ, Bönnemann CG, Emile-Backer M, Meilleur KG. Randomized controlled trial of N-acetylcysteine therapy for RYR1-related myopathies. Neurology 2020; 94:e1434-e1444. [PMID: 31941795 PMCID: PMC7274912 DOI: 10.1212/wnl.0000000000008872] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 09/09/2019] [Indexed: 11/29/2022] Open
Abstract
Objective To investigate the efficacy of N-acetylcysteine (NAC) for decreasing elevated oxidative stress and increasing physical endurance in individuals with ryanodine receptor 1-related myopathies (RYR1-RM). Methods In this 6-month natural history assessment (n = 37) followed by a randomized, double-blinded, placebo-controlled trial, 33 eligible participants were block-randomized (1:1) to receive NAC (n = 16) or placebo (n = 17), orally for 6 months (adult dose 2,700 mg/d; pediatric dose 30 mg/kg/d). The primary endpoint was urine 15-F2t isoprostane concentration and the clinically meaningful co-primary endpoint was 6-minute walk test (6MWT) distance. Results When compared to the general population, participants had elevated baseline 15-F2t isoprostane concentrations and most had a decreased 6MWT distance (mean ± SD 3.2 ± 1.5 vs 1.1 ± 1.7 ng/mg creatinine and 468 ± 134 vs 600 ± 58 m, respectively, both p < 0.001). 15-F2t isoprostane concentration and 6MWT distance did not change over the 6-month natural history assessment (p = 0.98 and p = 0.61, respectively). NAC treatment did not improve 15-F2t isoprostane concentration (least squares means difference 0.1 [95% confidence interval [CI] −1.4 to 1.6] ng/mg creatinine, p = 0.88) or 6MWT distance (least squares means difference 24 [95% CI −5.5 to 53.4] m, p = 0.11). NAC was safe and well-tolerated at the doses administered in this study. Conclusion In ambulatory RYR1-RM–affected individuals, we observed stable disease course, and corroborated preclinical reports of elevated oxidative stress and decreased physical endurance. NAC treatment did not decrease elevated oxidative stress, as measured by 15-F2t isoprostane. Classification of evidence This study provides Class I evidence that, for people with RYR1-RM, treatment with oral NAC does not decrease oxidative stress as measured by 15-F2t isoprostane. Clinicaltrials.gov identifier NCT02362425.
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Affiliation(s)
- Joshua J Todd
- From the Neuromuscular Symptoms Unit, National Institute of Nursing Research (J.J.T., T.A.L., J.W.W., I.C.C., M.S.R., M.P., J.S.E., F.T., A.K., M.O.S., C.A., M.M.C., M.L., M.E.-B., K.G.M.), Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department (M.S.J., M.W., B.D.), and Neurogenetics Branch, National Institute of Neurological Disorders and Stroke (C.G.B.), NIH, Bethesda, MD; Hyperion Biotechnology Inc. (D.M.), San Antonio, TX; Biostatistics and Clinical Epidemiology Service (P.G.W.), NIH Clinical Center, Bethesda, MD; Division of Neurology and Program for Genetics and Genome Biology (J.J.D.) and Departments of Paediatrics and Molecular Genetics (J.J.D.), Hospital for Sick Children, Toronto, Canada
| | - Tokunbor A Lawal
- From the Neuromuscular Symptoms Unit, National Institute of Nursing Research (J.J.T., T.A.L., J.W.W., I.C.C., M.S.R., M.P., J.S.E., F.T., A.K., M.O.S., C.A., M.M.C., M.L., M.E.-B., K.G.M.), Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department (M.S.J., M.W., B.D.), and Neurogenetics Branch, National Institute of Neurological Disorders and Stroke (C.G.B.), NIH, Bethesda, MD; Hyperion Biotechnology Inc. (D.M.), San Antonio, TX; Biostatistics and Clinical Epidemiology Service (P.G.W.), NIH Clinical Center, Bethesda, MD; Division of Neurology and Program for Genetics and Genome Biology (J.J.D.) and Departments of Paediatrics and Molecular Genetics (J.J.D.), Hospital for Sick Children, Toronto, Canada
| | - Jessica W Witherspoon
- From the Neuromuscular Symptoms Unit, National Institute of Nursing Research (J.J.T., T.A.L., J.W.W., I.C.C., M.S.R., M.P., J.S.E., F.T., A.K., M.O.S., C.A., M.M.C., M.L., M.E.-B., K.G.M.), Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department (M.S.J., M.W., B.D.), and Neurogenetics Branch, National Institute of Neurological Disorders and Stroke (C.G.B.), NIH, Bethesda, MD; Hyperion Biotechnology Inc. (D.M.), San Antonio, TX; Biostatistics and Clinical Epidemiology Service (P.G.W.), NIH Clinical Center, Bethesda, MD; Division of Neurology and Program for Genetics and Genome Biology (J.J.D.) and Departments of Paediatrics and Molecular Genetics (J.J.D.), Hospital for Sick Children, Toronto, Canada
| | - Irene C Chrismer
- From the Neuromuscular Symptoms Unit, National Institute of Nursing Research (J.J.T., T.A.L., J.W.W., I.C.C., M.S.R., M.P., J.S.E., F.T., A.K., M.O.S., C.A., M.M.C., M.L., M.E.-B., K.G.M.), Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department (M.S.J., M.W., B.D.), and Neurogenetics Branch, National Institute of Neurological Disorders and Stroke (C.G.B.), NIH, Bethesda, MD; Hyperion Biotechnology Inc. (D.M.), San Antonio, TX; Biostatistics and Clinical Epidemiology Service (P.G.W.), NIH Clinical Center, Bethesda, MD; Division of Neurology and Program for Genetics and Genome Biology (J.J.D.) and Departments of Paediatrics and Molecular Genetics (J.J.D.), Hospital for Sick Children, Toronto, Canada
| | - Muslima S Razaqyar
- From the Neuromuscular Symptoms Unit, National Institute of Nursing Research (J.J.T., T.A.L., J.W.W., I.C.C., M.S.R., M.P., J.S.E., F.T., A.K., M.O.S., C.A., M.M.C., M.L., M.E.-B., K.G.M.), Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department (M.S.J., M.W., B.D.), and Neurogenetics Branch, National Institute of Neurological Disorders and Stroke (C.G.B.), NIH, Bethesda, MD; Hyperion Biotechnology Inc. (D.M.), San Antonio, TX; Biostatistics and Clinical Epidemiology Service (P.G.W.), NIH Clinical Center, Bethesda, MD; Division of Neurology and Program for Genetics and Genome Biology (J.J.D.) and Departments of Paediatrics and Molecular Genetics (J.J.D.), Hospital for Sick Children, Toronto, Canada
| | - Monal Punjabi
- From the Neuromuscular Symptoms Unit, National Institute of Nursing Research (J.J.T., T.A.L., J.W.W., I.C.C., M.S.R., M.P., J.S.E., F.T., A.K., M.O.S., C.A., M.M.C., M.L., M.E.-B., K.G.M.), Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department (M.S.J., M.W., B.D.), and Neurogenetics Branch, National Institute of Neurological Disorders and Stroke (C.G.B.), NIH, Bethesda, MD; Hyperion Biotechnology Inc. (D.M.), San Antonio, TX; Biostatistics and Clinical Epidemiology Service (P.G.W.), NIH Clinical Center, Bethesda, MD; Division of Neurology and Program for Genetics and Genome Biology (J.J.D.) and Departments of Paediatrics and Molecular Genetics (J.J.D.), Hospital for Sick Children, Toronto, Canada
| | - Jeffrey S Elliott
- From the Neuromuscular Symptoms Unit, National Institute of Nursing Research (J.J.T., T.A.L., J.W.W., I.C.C., M.S.R., M.P., J.S.E., F.T., A.K., M.O.S., C.A., M.M.C., M.L., M.E.-B., K.G.M.), Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department (M.S.J., M.W., B.D.), and Neurogenetics Branch, National Institute of Neurological Disorders and Stroke (C.G.B.), NIH, Bethesda, MD; Hyperion Biotechnology Inc. (D.M.), San Antonio, TX; Biostatistics and Clinical Epidemiology Service (P.G.W.), NIH Clinical Center, Bethesda, MD; Division of Neurology and Program for Genetics and Genome Biology (J.J.D.) and Departments of Paediatrics and Molecular Genetics (J.J.D.), Hospital for Sick Children, Toronto, Canada
| | - Fatoumata Tounkara
- From the Neuromuscular Symptoms Unit, National Institute of Nursing Research (J.J.T., T.A.L., J.W.W., I.C.C., M.S.R., M.P., J.S.E., F.T., A.K., M.O.S., C.A., M.M.C., M.L., M.E.-B., K.G.M.), Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department (M.S.J., M.W., B.D.), and Neurogenetics Branch, National Institute of Neurological Disorders and Stroke (C.G.B.), NIH, Bethesda, MD; Hyperion Biotechnology Inc. (D.M.), San Antonio, TX; Biostatistics and Clinical Epidemiology Service (P.G.W.), NIH Clinical Center, Bethesda, MD; Division of Neurology and Program for Genetics and Genome Biology (J.J.D.) and Departments of Paediatrics and Molecular Genetics (J.J.D.), Hospital for Sick Children, Toronto, Canada
| | - Anna Kuo
- From the Neuromuscular Symptoms Unit, National Institute of Nursing Research (J.J.T., T.A.L., J.W.W., I.C.C., M.S.R., M.P., J.S.E., F.T., A.K., M.O.S., C.A., M.M.C., M.L., M.E.-B., K.G.M.), Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department (M.S.J., M.W., B.D.), and Neurogenetics Branch, National Institute of Neurological Disorders and Stroke (C.G.B.), NIH, Bethesda, MD; Hyperion Biotechnology Inc. (D.M.), San Antonio, TX; Biostatistics and Clinical Epidemiology Service (P.G.W.), NIH Clinical Center, Bethesda, MD; Division of Neurology and Program for Genetics and Genome Biology (J.J.D.) and Departments of Paediatrics and Molecular Genetics (J.J.D.), Hospital for Sick Children, Toronto, Canada
| | - Monique O Shelton
- From the Neuromuscular Symptoms Unit, National Institute of Nursing Research (J.J.T., T.A.L., J.W.W., I.C.C., M.S.R., M.P., J.S.E., F.T., A.K., M.O.S., C.A., M.M.C., M.L., M.E.-B., K.G.M.), Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department (M.S.J., M.W., B.D.), and Neurogenetics Branch, National Institute of Neurological Disorders and Stroke (C.G.B.), NIH, Bethesda, MD; Hyperion Biotechnology Inc. (D.M.), San Antonio, TX; Biostatistics and Clinical Epidemiology Service (P.G.W.), NIH Clinical Center, Bethesda, MD; Division of Neurology and Program for Genetics and Genome Biology (J.J.D.) and Departments of Paediatrics and Molecular Genetics (J.J.D.), Hospital for Sick Children, Toronto, Canada
| | - Carolyn Allen
- From the Neuromuscular Symptoms Unit, National Institute of Nursing Research (J.J.T., T.A.L., J.W.W., I.C.C., M.S.R., M.P., J.S.E., F.T., A.K., M.O.S., C.A., M.M.C., M.L., M.E.-B., K.G.M.), Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department (M.S.J., M.W., B.D.), and Neurogenetics Branch, National Institute of Neurological Disorders and Stroke (C.G.B.), NIH, Bethesda, MD; Hyperion Biotechnology Inc. (D.M.), San Antonio, TX; Biostatistics and Clinical Epidemiology Service (P.G.W.), NIH Clinical Center, Bethesda, MD; Division of Neurology and Program for Genetics and Genome Biology (J.J.D.) and Departments of Paediatrics and Molecular Genetics (J.J.D.), Hospital for Sick Children, Toronto, Canada
| | - Mary M Cosgrove
- From the Neuromuscular Symptoms Unit, National Institute of Nursing Research (J.J.T., T.A.L., J.W.W., I.C.C., M.S.R., M.P., J.S.E., F.T., A.K., M.O.S., C.A., M.M.C., M.L., M.E.-B., K.G.M.), Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department (M.S.J., M.W., B.D.), and Neurogenetics Branch, National Institute of Neurological Disorders and Stroke (C.G.B.), NIH, Bethesda, MD; Hyperion Biotechnology Inc. (D.M.), San Antonio, TX; Biostatistics and Clinical Epidemiology Service (P.G.W.), NIH Clinical Center, Bethesda, MD; Division of Neurology and Program for Genetics and Genome Biology (J.J.D.) and Departments of Paediatrics and Molecular Genetics (J.J.D.), Hospital for Sick Children, Toronto, Canada
| | - Melody Linton
- From the Neuromuscular Symptoms Unit, National Institute of Nursing Research (J.J.T., T.A.L., J.W.W., I.C.C., M.S.R., M.P., J.S.E., F.T., A.K., M.O.S., C.A., M.M.C., M.L., M.E.-B., K.G.M.), Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department (M.S.J., M.W., B.D.), and Neurogenetics Branch, National Institute of Neurological Disorders and Stroke (C.G.B.), NIH, Bethesda, MD; Hyperion Biotechnology Inc. (D.M.), San Antonio, TX; Biostatistics and Clinical Epidemiology Service (P.G.W.), NIH Clinical Center, Bethesda, MD; Division of Neurology and Program for Genetics and Genome Biology (J.J.D.) and Departments of Paediatrics and Molecular Genetics (J.J.D.), Hospital for Sick Children, Toronto, Canada
| | - Darren Michael
- From the Neuromuscular Symptoms Unit, National Institute of Nursing Research (J.J.T., T.A.L., J.W.W., I.C.C., M.S.R., M.P., J.S.E., F.T., A.K., M.O.S., C.A., M.M.C., M.L., M.E.-B., K.G.M.), Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department (M.S.J., M.W., B.D.), and Neurogenetics Branch, National Institute of Neurological Disorders and Stroke (C.G.B.), NIH, Bethesda, MD; Hyperion Biotechnology Inc. (D.M.), San Antonio, TX; Biostatistics and Clinical Epidemiology Service (P.G.W.), NIH Clinical Center, Bethesda, MD; Division of Neurology and Program for Genetics and Genome Biology (J.J.D.) and Departments of Paediatrics and Molecular Genetics (J.J.D.), Hospital for Sick Children, Toronto, Canada
| | - Minal S Jain
- From the Neuromuscular Symptoms Unit, National Institute of Nursing Research (J.J.T., T.A.L., J.W.W., I.C.C., M.S.R., M.P., J.S.E., F.T., A.K., M.O.S., C.A., M.M.C., M.L., M.E.-B., K.G.M.), Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department (M.S.J., M.W., B.D.), and Neurogenetics Branch, National Institute of Neurological Disorders and Stroke (C.G.B.), NIH, Bethesda, MD; Hyperion Biotechnology Inc. (D.M.), San Antonio, TX; Biostatistics and Clinical Epidemiology Service (P.G.W.), NIH Clinical Center, Bethesda, MD; Division of Neurology and Program for Genetics and Genome Biology (J.J.D.) and Departments of Paediatrics and Molecular Genetics (J.J.D.), Hospital for Sick Children, Toronto, Canada
| | - Melissa Waite
- From the Neuromuscular Symptoms Unit, National Institute of Nursing Research (J.J.T., T.A.L., J.W.W., I.C.C., M.S.R., M.P., J.S.E., F.T., A.K., M.O.S., C.A., M.M.C., M.L., M.E.-B., K.G.M.), Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department (M.S.J., M.W., B.D.), and Neurogenetics Branch, National Institute of Neurological Disorders and Stroke (C.G.B.), NIH, Bethesda, MD; Hyperion Biotechnology Inc. (D.M.), San Antonio, TX; Biostatistics and Clinical Epidemiology Service (P.G.W.), NIH Clinical Center, Bethesda, MD; Division of Neurology and Program for Genetics and Genome Biology (J.J.D.) and Departments of Paediatrics and Molecular Genetics (J.J.D.), Hospital for Sick Children, Toronto, Canada
| | - Bart Drinkard
- From the Neuromuscular Symptoms Unit, National Institute of Nursing Research (J.J.T., T.A.L., J.W.W., I.C.C., M.S.R., M.P., J.S.E., F.T., A.K., M.O.S., C.A., M.M.C., M.L., M.E.-B., K.G.M.), Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department (M.S.J., M.W., B.D.), and Neurogenetics Branch, National Institute of Neurological Disorders and Stroke (C.G.B.), NIH, Bethesda, MD; Hyperion Biotechnology Inc. (D.M.), San Antonio, TX; Biostatistics and Clinical Epidemiology Service (P.G.W.), NIH Clinical Center, Bethesda, MD; Division of Neurology and Program for Genetics and Genome Biology (J.J.D.) and Departments of Paediatrics and Molecular Genetics (J.J.D.), Hospital for Sick Children, Toronto, Canada
| | - Paul G Wakim
- From the Neuromuscular Symptoms Unit, National Institute of Nursing Research (J.J.T., T.A.L., J.W.W., I.C.C., M.S.R., M.P., J.S.E., F.T., A.K., M.O.S., C.A., M.M.C., M.L., M.E.-B., K.G.M.), Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department (M.S.J., M.W., B.D.), and Neurogenetics Branch, National Institute of Neurological Disorders and Stroke (C.G.B.), NIH, Bethesda, MD; Hyperion Biotechnology Inc. (D.M.), San Antonio, TX; Biostatistics and Clinical Epidemiology Service (P.G.W.), NIH Clinical Center, Bethesda, MD; Division of Neurology and Program for Genetics and Genome Biology (J.J.D.) and Departments of Paediatrics and Molecular Genetics (J.J.D.), Hospital for Sick Children, Toronto, Canada
| | - James J Dowling
- From the Neuromuscular Symptoms Unit, National Institute of Nursing Research (J.J.T., T.A.L., J.W.W., I.C.C., M.S.R., M.P., J.S.E., F.T., A.K., M.O.S., C.A., M.M.C., M.L., M.E.-B., K.G.M.), Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department (M.S.J., M.W., B.D.), and Neurogenetics Branch, National Institute of Neurological Disorders and Stroke (C.G.B.), NIH, Bethesda, MD; Hyperion Biotechnology Inc. (D.M.), San Antonio, TX; Biostatistics and Clinical Epidemiology Service (P.G.W.), NIH Clinical Center, Bethesda, MD; Division of Neurology and Program for Genetics and Genome Biology (J.J.D.) and Departments of Paediatrics and Molecular Genetics (J.J.D.), Hospital for Sick Children, Toronto, Canada
| | - Carsten G Bönnemann
- From the Neuromuscular Symptoms Unit, National Institute of Nursing Research (J.J.T., T.A.L., J.W.W., I.C.C., M.S.R., M.P., J.S.E., F.T., A.K., M.O.S., C.A., M.M.C., M.L., M.E.-B., K.G.M.), Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department (M.S.J., M.W., B.D.), and Neurogenetics Branch, National Institute of Neurological Disorders and Stroke (C.G.B.), NIH, Bethesda, MD; Hyperion Biotechnology Inc. (D.M.), San Antonio, TX; Biostatistics and Clinical Epidemiology Service (P.G.W.), NIH Clinical Center, Bethesda, MD; Division of Neurology and Program for Genetics and Genome Biology (J.J.D.) and Departments of Paediatrics and Molecular Genetics (J.J.D.), Hospital for Sick Children, Toronto, Canada
| | - Magalie Emile-Backer
- From the Neuromuscular Symptoms Unit, National Institute of Nursing Research (J.J.T., T.A.L., J.W.W., I.C.C., M.S.R., M.P., J.S.E., F.T., A.K., M.O.S., C.A., M.M.C., M.L., M.E.-B., K.G.M.), Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department (M.S.J., M.W., B.D.), and Neurogenetics Branch, National Institute of Neurological Disorders and Stroke (C.G.B.), NIH, Bethesda, MD; Hyperion Biotechnology Inc. (D.M.), San Antonio, TX; Biostatistics and Clinical Epidemiology Service (P.G.W.), NIH Clinical Center, Bethesda, MD; Division of Neurology and Program for Genetics and Genome Biology (J.J.D.) and Departments of Paediatrics and Molecular Genetics (J.J.D.), Hospital for Sick Children, Toronto, Canada
| | - Katherine G Meilleur
- From the Neuromuscular Symptoms Unit, National Institute of Nursing Research (J.J.T., T.A.L., J.W.W., I.C.C., M.S.R., M.P., J.S.E., F.T., A.K., M.O.S., C.A., M.M.C., M.L., M.E.-B., K.G.M.), Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department (M.S.J., M.W., B.D.), and Neurogenetics Branch, National Institute of Neurological Disorders and Stroke (C.G.B.), NIH, Bethesda, MD; Hyperion Biotechnology Inc. (D.M.), San Antonio, TX; Biostatistics and Clinical Epidemiology Service (P.G.W.), NIH Clinical Center, Bethesda, MD; Division of Neurology and Program for Genetics and Genome Biology (J.J.D.) and Departments of Paediatrics and Molecular Genetics (J.J.D.), Hospital for Sick Children, Toronto, Canada.
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Todd JJ, Sagar V, Lawal TA, Allen C, Razaqyar MS, Shelton MS, Chrismer IC, Zhang X, Cosgrove MM, Kuo A, Vasavada R, Jain MS, Waite M, Rajapakse D, Witherspoon JW, Wistow G, Meilleur KG. Correlation of phenotype with genotype and protein structure in RYR1-related disorders. J Neurol 2018; 265:2506-2524. [PMID: 30155738 PMCID: PMC6182665 DOI: 10.1007/s00415-018-9033-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 08/17/2018] [Accepted: 08/18/2018] [Indexed: 01/01/2023]
Abstract
Variants in the skeletal muscle ryanodine receptor 1 gene (RYR1) result in a spectrum of RYR1-related disorders. Presentation during infancy is typical and ranges from delayed motor milestones and proximal muscle weakness to severe respiratory impairment and ophthalmoplegia. We aimed to elucidate correlations between genotype, protein structure and clinical phenotype in this rare disease population. Genetic and clinical data from 47 affected individuals were analyzed and variants mapped to the cryo-EM RyR1 structure. Comparisons of clinical severity, motor and respiratory function and symptomatology were made according to the mode of inheritance and affected RyR1 structural domain(s). Overall, 49 RYR1 variants were identified in 47 cases (dominant/de novo, n = 35; recessive, n = 12). Three variants were previously unreported. In recessive cases, facial weakness, neonatal hypotonia, ophthalmoplegia/paresis, ptosis, and scapular winging were more frequently observed than in dominant/de novo cases (all, p < 0.05). Both dominant/de novo and recessive cases exhibited core myopathy histopathology. Clinically severe cases were typically recessive or had variants localized to the RyR1 cytosolic shell domain. Motor deficits were most apparent in the MFM-32 standing and transfers dimension, [median (IQR) 85.4 (18.8)% of maximum score] and recessive cases exhibited significantly greater overall motor function impairment compared to dominant/de novo cases [79.7 (18.8)% vs. 87.5 (17.7)% of maximum score, p = 0.03]. Variant mapping revealed patterns of clinical severity across RyR1 domains, including a structural plane of interest within the RyR1 cytosolic shell, in which 84% of variants affected the bridging solenoid. We have corroborated genotype-phenotype correlations and identified RyR1 regions that may be especially sensitive to structural modification.
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Affiliation(s)
- Joshua J Todd
- Neuromuscular Symptoms Unit, Tissue Injury Branch, National Institute of Nursing Research, National Institutes of Health, 10 Center Drive, Room 2A07, Bethesda, MD, 20892, USA.
| | - Vatsala Sagar
- Section on Molecular Structure and Functional Genomics, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Tokunbor A Lawal
- Neuromuscular Symptoms Unit, Tissue Injury Branch, National Institute of Nursing Research, National Institutes of Health, 10 Center Drive, Room 2A07, Bethesda, MD, 20892, USA
| | - Carolyn Allen
- Neuromuscular Symptoms Unit, Tissue Injury Branch, National Institute of Nursing Research, National Institutes of Health, 10 Center Drive, Room 2A07, Bethesda, MD, 20892, USA
| | - Muslima S Razaqyar
- Neuromuscular Symptoms Unit, Tissue Injury Branch, National Institute of Nursing Research, National Institutes of Health, 10 Center Drive, Room 2A07, Bethesda, MD, 20892, USA
| | - Monique S Shelton
- Neuromuscular Symptoms Unit, Tissue Injury Branch, National Institute of Nursing Research, National Institutes of Health, 10 Center Drive, Room 2A07, Bethesda, MD, 20892, USA
| | - Irene C Chrismer
- Neuromuscular Symptoms Unit, Tissue Injury Branch, National Institute of Nursing Research, National Institutes of Health, 10 Center Drive, Room 2A07, Bethesda, MD, 20892, USA
| | - Xuemin Zhang
- Neuromuscular Symptoms Unit, Tissue Injury Branch, National Institute of Nursing Research, National Institutes of Health, 10 Center Drive, Room 2A07, Bethesda, MD, 20892, USA
| | - Mary M Cosgrove
- Neuromuscular Symptoms Unit, Tissue Injury Branch, National Institute of Nursing Research, National Institutes of Health, 10 Center Drive, Room 2A07, Bethesda, MD, 20892, USA
| | - Anna Kuo
- Neuromuscular Symptoms Unit, Tissue Injury Branch, National Institute of Nursing Research, National Institutes of Health, 10 Center Drive, Room 2A07, Bethesda, MD, 20892, USA
| | - Ruhi Vasavada
- Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department, National Institutes of Health, Bethesda, MD, USA
| | - Minal S Jain
- Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department, National Institutes of Health, Bethesda, MD, USA
| | - Melissa Waite
- Mark O. Hatfield Clinical Research Center, Rehabilitation Medicine Department, National Institutes of Health, Bethesda, MD, USA
| | - Dinusha Rajapakse
- Section on Molecular Structure and Functional Genomics, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jessica W Witherspoon
- Neuromuscular Symptoms Unit, Tissue Injury Branch, National Institute of Nursing Research, National Institutes of Health, 10 Center Drive, Room 2A07, Bethesda, MD, 20892, USA
| | - Graeme Wistow
- Section on Molecular Structure and Functional Genomics, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Katherine G Meilleur
- Neuromuscular Symptoms Unit, Tissue Injury Branch, National Institute of Nursing Research, National Institutes of Health, 10 Center Drive, Room 2A07, Bethesda, MD, 20892, USA
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