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Benucci S, Ruiz A, Franchini M, Ruggiero L, Zoppi D, Sitsapesan R, Lindsay C, Pelczar P, Pietrangelo L, Protasi F, Treves S, Zorzato F. A novel, patient-derived RyR1 mutation impairs muscle function and calcium homeostasis in mice. J Gen Physiol 2024; 156:e202313486. [PMID: 38445312 PMCID: PMC10911087 DOI: 10.1085/jgp.202313486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 12/20/2023] [Accepted: 02/09/2024] [Indexed: 03/07/2024] Open
Abstract
RYR1 is the most commonly mutated gene associated with congenital myopathies, a group of early-onset neuromuscular conditions of variable severity. The functional effects of a number of dominant RYR1 mutations have been established; however, for recessive mutations, these effects may depend on multiple factors, such as the formation of a hypomorphic allele, or on whether they are homozygous or compound heterozygous. Here, we functionally characterize a new transgenic mouse model knocked-in for mutations identified in a severely affected child born preterm and presenting limited limb movement. The child carried the homozygous c.14928C>G RYR1 mutation, resulting in the p.F4976L substitution. In vivo and ex vivo assays revealed that homozygous mice fatigued sooner and their muscles generated significantly less force compared with their WT or heterozygous littermates. Electron microscopy, biochemical, and physiological analyses showed that muscles from RyR1 p.F4976L homozygous mice have the following properties: (1) contain fewer calcium release units and show areas of myofibrillar degeneration, (2) contain less RyR1 protein, (3) fibers show smaller electrically evoked calcium transients, and (4) their SR has smaller calcium stores. In addition, single-channel recordings indicate that RyR1 p.F4976L exhibits higher Po in the presence of 100 μM [Ca2+]. Our mouse model partly recapitulates the clinical picture of the homozygous human patient and provides significant insight into the functional impact of this mutation. These results will help understand the pathology of patients with similar RYR1 mutations.
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Affiliation(s)
- Sofia Benucci
- Departments of Biomedicine and Neurology, Basel University Hospital, Basel, Switzerland
| | - Alexis Ruiz
- Departments of Biomedicine and Neurology, Basel University Hospital, Basel, Switzerland
| | - Martina Franchini
- Departments of Biomedicine and Neurology, Basel University Hospital, Basel, Switzerland
| | - Lucia Ruggiero
- Dipartimento di Neuroscienze, Scienze Riproduttive ed Odontostomatologiche, Università degli Studi di Napoli Federico II, Napoli, Italy
| | - Dario Zoppi
- Dipartimento di Neuroscienze, Scienze Riproduttive ed Odontostomatologiche, Università degli Studi di Napoli Federico II, Napoli, Italy
| | | | - Chris Lindsay
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Pawel Pelczar
- Center for Transgenic Models, University of Basel, Basel, Switzerland
| | - Laura Pietrangelo
- DMSI, Department of Medicine and Aging Sciences and CAST, Center for Advanced Studies and Technology, University G. d’Annunzio of Chieti-Pescara, Chieti, Italy
| | - Feliciano Protasi
- DMSI, Department of Medicine and Aging Sciences and CAST, Center for Advanced Studies and Technology, University G. d’Annunzio of Chieti-Pescara, Chieti, Italy
| | - Susan Treves
- Departments of Biomedicine and Neurology, Basel University Hospital, Basel, Switzerland
- Department of Life Science and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Francesco Zorzato
- Departments of Biomedicine and Neurology, Basel University Hospital, Basel, Switzerland
- Department of Life Science and Biotechnology, University of Ferrara, Ferrara, Italy
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Dori A, Scutifero M, Passamano L, Zoppi D, Ruggiero L, Trabacca A, Politano L. Treatment with ataluren in four symptomatic Duchenne carriers. A pilot study. Acta Myol 2024; 43:8-15. [PMID: 38586166 PMCID: PMC10997039 DOI: 10.36185/2532-1900-398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 02/01/2024] [Indexed: 04/09/2024]
Abstract
Duchenne muscular dystrophy (DMD) is a devastating X-linked neuromuscular disorder caused by dystrophin gene deletions (75%), duplications (15-20%) and point mutations (5-10%), a small portion of which are nonsense mutations. Women carrying dystrophin gene mutations are commonly unaffected because the wild X allele may produce a sufficient amount of the dystrophin protein. However, approximately 8-10% of them may experience muscle symptoms and 50% of those over 40 years develop cardiomyopathy. The presence of symptoms defines the individual as an affected "symptomatic or manifesting carrier". Though there is no effective cure for DMD, therapies are available to slow the decline of muscle strength and delay the onset and progression of cardiac and respiratory impairment. These include ataluren for patients with nonsense mutations, and antisense oligonucleotides therapies, for patients with specific deletions. Symptomatic DMD female carriers are not included in these indications and little data documenting their management, often entrusted to the discretion of individual doctors, is present in the literature. In this article, we report the clinical and instrumental outcomes of four symptomatic DMD carriers, aged between 26 and 45 years, who were treated with ataluren for 21 to 73 months (average 47.3), and annually evaluated for muscle strength, respiratory and cardiological function. Two patients retain independent ambulation at ages 33 and 45, respectively. None of them developed respiratory involvement or cardiomyopathy. No clinical adverse effects or relevant abnormalities in routine laboratory values, were observed.
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Affiliation(s)
- Amir Dori
- Department of Neurology, Chaim Sheba Medical Center, HaShomer, and Joseph Sagol Neuroscience Center, Faculty of Medicine, Aviv University, Aviv, Israel
| | - Marianna Scutifero
- Cardiomyology and Medical Genetics, University of Campania Luigi Vanvitelli, Naples, Italy
| | - Luigia Passamano
- Cardiomyology and Medical Genetics, University of Campania Luigi Vanvitelli, Naples, Italy
| | - Dario Zoppi
- Department of Neurosciences, Reproductive and Odontostomatological Sciences, University of Naples “Federico II”, Naples, Italy
| | - Lucia Ruggiero
- Department of Neurosciences, Reproductive and Odontostomatological Sciences, University of Naples “Federico II”, Naples, Italy
| | - Antonio Trabacca
- Scientific Institute IRCCS “E. Medea”, Unit for Severe disabilities in developmental age and young adults (Developmental Neurology and Neurorehabilitation), Brindisi, Italy
| | - Luisa Politano
- Cardiomyology and Medical Genetics, University of Campania Luigi Vanvitelli, Naples, Italy
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Bencivenga RP, Zoppi D, Russo A, Cassano E, Tozza S, Iodice R, Dubbioso R, Manganelli F, Ruggiero L. Pregnancy experience in women with spinal muscular atrophy: a case series. Acta Myol 2023; 42:60-64. [PMID: 38090543 PMCID: PMC10712658 DOI: 10.36185/2532-1900-316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Accepted: 09/26/2023] [Indexed: 12/18/2023]
Abstract
Many women with spinal muscular atrophy (SMA) types II, III, and IV reach fertile age, and some of them may consider pregnancy. However, limited data are available about the potential effects of pregnancy on the course of SMA and the outcomes of pregnancies in these patients. Furthermore, the use of several disease-modifying therapies for the treatment of all types of SMA is expected to increase the number of female SMA patients considering pregnancy in the coming years. The aim of this report is to provide clinicians with an overview of the patients in our cohort who have experienced pregnancies. We conducted a retrospective analysis on these women, through the administration of a questionnaire, which investigated how they experienced the different stages of the pregnancy. Ten patients (3 SMAII; 7 SMA III) participated in the survey; 40% had pregnancies for a total of nine, six of which were term-pregnancies. The mean age of first pregnancy was 32.5 ± 7.8 years for SMA II patients, and 30.5 ± 2.1 years for SMA III. All pregnancies ended in cesarean sections. Interestingly, the sitters had more frequent complications in pre-term labor and delivery, but the newborns were all healthy. This report shows that a successful pregnancy is possible in female patients with SMA. However, the ideal approach should involve a standardized multidisciplinary team capable of effectively addressing every possible scenario. For this reason, it is critically important that clinicians working with SMA patients gain more in-dept knowledge about this topic.
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Affiliation(s)
- Roberta Piera Bencivenga
- Department of Neurosciences, Reproductive and Odontostomatological Sciences, University of Naples “Federico II”, Naples, Italy
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