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Valls A, Gutiérrez-Gutiérrez G, Martínez A, Ruiz-Roldán C, Camaño P, López de Munain A, Sáenz A. The CAPN3 p.Lys 254del variant is not always associated with dominant CAPN3-related muscular dystrophy. Muscle Nerve 2024; 69:472-476. [PMID: 38299438 DOI: 10.1002/mus.28045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 01/09/2024] [Accepted: 01/14/2024] [Indexed: 02/02/2024]
Abstract
INTRODUCTION/AIMS Limb-girdle muscular dystrophy R1 (LGMDR1) calpain 3-related usually presents as a recessively transmitted weakness of proximal limb-girdle muscles due to pathogenic variants in the CAPN3 gene. Pathogenic variants in this gene have also been found in patients with an autosomal dominantly inherited transmission pattern (LGMDD4). The mechanism underlying this difference in transmission patterns has not yet been elucidated. Camptocormia, progressive limb weakness, myalgia, back pain, and increased CK levels are common clinical features associated with dominant forms. The p.Lys254del pathogenic variant was associated with camptocormia in two LGMDD4 families. This study aimed to present carriers found in recessively transmitted LGMDR1 families bearing the p.Lys254del variant that do not show muscle weakness. METHODS DNA sequencing was performed on exon 5 of CAPN3 in family members to establish the carrier status of the pathogenic variant. They were evaluated clinically and MRI was performed when available. RESULTS Two families presented with the p.Lys254del pathogenic variant in a homozygous or compound heterozygous state. Family members carrying only the pathogenic variant in the heterozygous state did not demonstrate the myopathic characteristics described in dominant patients. Camptocormia and other severe clinical symptoms were not observed. DISCUSSION We conclude that the p.Lys254del pathogenic variant per se cannot be solely responsible for camptocormia in dominant patients. Other undisclosed factors may regulate the phenotype associated with the dominant inheritance pattern in CAPN3 pathogenic variant carriers.
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Affiliation(s)
- Andrea Valls
- Neurosciences Area, Biodonostia Health Research Institute, San Sebastian, Spain
- CIBERNED, CIBER, Spanish Ministry of Science & Innovation, Carlos III Health Institute, Madrid, Spain
| | - Gerardo Gutiérrez-Gutiérrez
- CIBERNED, CIBER, Spanish Ministry of Science & Innovation, Carlos III Health Institute, Madrid, Spain
- Department of Neurology, Hospital Universitario Infanta Sofía, Madrid, Spain
- Neuromuscular Diseases Unit, Universidad Europea de Madrid, Madrid, Spain
| | | | - Cristina Ruiz-Roldán
- Neurosciences Area, Biodonostia Health Research Institute, San Sebastian, Spain
- CIBERNED, CIBER, Spanish Ministry of Science & Innovation, Carlos III Health Institute, Madrid, Spain
| | - Pilar Camaño
- Neurosciences Area, Biodonostia Health Research Institute, San Sebastian, Spain
- CIBERNED, CIBER, Spanish Ministry of Science & Innovation, Carlos III Health Institute, Madrid, Spain
- Molecular Diagnostics Platform, Biodonostia Health Research Institute, San Sebastian, Spain
| | - Adolfo López de Munain
- Neurosciences Area, Biodonostia Health Research Institute, San Sebastian, Spain
- CIBERNED, CIBER, Spanish Ministry of Science & Innovation, Carlos III Health Institute, Madrid, Spain
- Department of Neurology, Donostialdea Integrated Health Organisation, Osakidetza, San Sebastian, Spain
- Department of Neurosciences, University of the Basque Country UPV-EHU, San Sebastian, Spain
- Faculty of Medicine, University of Deusto, Bilbao, Spain
| | - Amets Sáenz
- Neurosciences Area, Biodonostia Health Research Institute, San Sebastian, Spain
- CIBERNED, CIBER, Spanish Ministry of Science & Innovation, Carlos III Health Institute, Madrid, Spain
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Macias A, Fichna JP, Topolewska M, Rȩdowicz MJ, Kaminska AM, Kostera-Pruszczyk A. Targeted Next-Generation Sequencing Reveals Mutations in Non-coding Regions and Potential Regulatory Sequences of Calpain-3 Gene in Polish Limb-Girdle Muscular Dystrophy Patients. Front Neurosci 2021; 15:692482. [PMID: 34720847 PMCID: PMC8551377 DOI: 10.3389/fnins.2021.692482] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 09/17/2021] [Indexed: 01/22/2023] Open
Abstract
Limb–girdle muscular dystrophy type R1 (LGMDR1) is caused by mutations in CAPN3 and is the most common type of recessive LGMD. Even with the use of whole-exome sequencing (WES), only one mutant allele of CAPN3 is found in a significant number of LGMDR patients. This points to a role of non-coding, intronic or regulatory, sequence variants in the disease pathogenesis. Targeted sequencing of the whole CAPN3 gene including not only intronic, 3′ and 5′ UTRs but also potential regulatory regions was performed in 27 patients suspected with LGMDR1. This group included 13 patients with only one mutated CAPN3 allele detected previously with exome sequencing. A second rare variant in the non-coding part of CAPN3 was found in 11 of 13 patients with previously identified single mutation. Intronic mutations were found in 10 cases, with c.1746-20C>G variant present in seven patients. In addition, a large deletion of exons 2–8 was found in one patient. In the patients with no causative mutation previously found, we detected rare CAPN3 variants in 5 out of 10 patients and in two of them in a compound heterozygous state. Rare variants within putative regulatory sequences distant from the CAPN3 gene were found in 15 patients, although in 11 of these cases, other variants are deemed causative. The results indicate that intronic mutations are common in Polish LGMDR patients, and testing for non-coding mutations in CAPN3 should be performed in apparently single heterozygous patients.
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Affiliation(s)
- Anna Macias
- Department of Neurology, Medical University of Warsaw, Warsaw, Poland
| | - Jakub Piotr Fichna
- Laboratory of Neurogenetics, Department of Neurodegenerative Disorders, Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Malgorzata Topolewska
- Laboratory of Molecular Basis of Cell Motility, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Maria J Rȩdowicz
- Laboratory of Molecular Basis of Cell Motility, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Anna M Kaminska
- Department of Neurology, Medical University of Warsaw, Warsaw, Poland
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