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Jablonka S, Yildirim E. Disease Mechanisms and Therapeutic Approaches in SMARD1-Insights from Animal Models and Cell Models. Biomedicines 2024; 12:845. [PMID: 38672198 PMCID: PMC11048220 DOI: 10.3390/biomedicines12040845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 04/04/2024] [Accepted: 04/07/2024] [Indexed: 04/28/2024] Open
Abstract
Spinal muscular atrophy with respiratory distress type 1 (SMARD1) is a fatal childhood motoneuron disease caused by mutations in the IGHMBP2 gene. It is characterized by muscle weakness, initially affecting the distal extremities due to the degeneration of spinal α-motoneurons, and respiratory distress, due to the paralysis of the diaphragm. Infantile forms with a severe course of the disease can be distinguished from juvenile forms with a milder course. Mutations in the IGHMBP2 gene have also been found in patients with peripheral neuropathy Charcot-Marie-Tooth type 2S (CMT2S). IGHMBP2 is an ATP-dependent 5'→3' RNA helicase thought to be involved in translational mechanisms. In recent years, several animal models representing both SMARD1 forms and CMT2S have been generated to initially study disease mechanisms. Later, the models showed very well that both stem cell therapies and the delivery of the human IGHMBP2 cDNA by AAV9 approaches (AAV9-IGHMBP2) can lead to significant improvements in disease symptoms. Therefore, the SMARD1 animal models, in addition to the cellular models, provide an inexhaustible source for obtaining knowledge of disease mechanisms, disease progression at the cellular level, and deeper insights into the development of therapies against SMARD1.
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Affiliation(s)
- Sibylle Jablonka
- Institute of Clinical Neurobiology, University Hospital Würzburg, Versbacher Strasse 5, 97078 Würzburg, Germany;
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Tran VK, Cao MH, Nguyen TTH, Le PT, Tran HA, Vu DC, Nguyen HT, Nguyen MTP, Bui TH, Nguyen TB, Ta TV, Tran TH. A novel IGHMBP2 variant and clinical diversity in Vietnamese SMARD1 and CMT2S patients. Front Pediatr 2024; 12:1165492. [PMID: 38415210 PMCID: PMC10896978 DOI: 10.3389/fped.2024.1165492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 01/26/2024] [Indexed: 02/29/2024] Open
Abstract
Background Pathogenic variants in the IGHMBP2 gene are associated with two distinct autosomal recessive neuromuscular disorders: spinal muscular atrophy with respiratory distress type 1 (SMARD1; OMIM #604320) and Charcot-Marie-Tooth type 2S (CMT2S; OMIM #616155). SMARD1 is a severe and fatal condition characterized by infantile-onset respiratory distress, diaphragmatic palsy, and distal muscular weakness, while CMT2S follows a milder clinical course, with slowly progressive distal muscle weakness and sensory loss, without manifestations of respiratory disorder. Methods Whole-exome sequencing of the IGHMBP2 gene was performed for eight Vietnamese patients with IGHMBP2-related neuromuscular disorders including five patients with SMARD1 and the others with CMT2S. Results We identified one novel IGHMBP2 variant c.1574T > C (p.Leu525Pro) in a SMARD1 patient. Besides that, two patients shared the same pathogenic variants (c.1235 + 3A > G/c.1334A > C) but presented completely different clinical courses: one with SMARD1 who deceased at 8 months of age, the other with CMT2S was alive at 3 years old without any respiratory distress. Conclusion This study is the first to report IGHMBP-2-related neuromuscular disorders in Vietnam. A novel IGHMBP2 variant c.1574T > C (p.Leu525Pro) expressing SMARD1 phenotype was detected. The presence of three patients with the same genotype but distinct clinical outcomes suggested the interaction of variants and other factors including relating modified genes in the mechanism of various phenotypes.
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Affiliation(s)
- Van Khanh Tran
- Center for Gene and Protein Research, Hanoi Medical University, Hanoi, Vietnam
- Department of Molecular Pathology, Faculty of Medical Laboratory Technology, Hanoi Medical University, Hanoi, Vietnam
| | - My Ha Cao
- Center for Gene and Protein Research, Hanoi Medical University, Hanoi, Vietnam
| | | | - Phuong Thi Le
- Center for Gene and Protein Research, Hanoi Medical University, Hanoi, Vietnam
| | - Hai Anh Tran
- Center for Gene and Protein Research, Hanoi Medical University, Hanoi, Vietnam
| | - Dung Chi Vu
- Department of Endocrinology, Metabolism and Genetics, National Hospital of Pediatrics, Hanoi, Vietnam
| | - Ha Thu Nguyen
- Department of Endocrinology, Metabolism and Genetics, National Hospital of Pediatrics, Hanoi, Vietnam
| | | | - The-Hung Bui
- Center for Gene and Protein Research, Hanoi Medical University, Hanoi, Vietnam
- Center for Molecular Medicine, Clinical Genetics Unit, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden
| | - Thanh Binh Nguyen
- Center for Gene and Protein Research, Hanoi Medical University, Hanoi, Vietnam
| | - Thanh Van Ta
- Department of Biochemistry, Hanoi Medical University, Hanoi, Vietnam
- Clinical Laboratory, Hanoi Medical University Hospital, Hanoi Medical University, Hanoi, Vietnam
| | - Thinh Huy Tran
- Department of Biochemistry, Hanoi Medical University, Hanoi, Vietnam
- Clinical Laboratory, Hanoi Medical University Hospital, Hanoi Medical University, Hanoi, Vietnam
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Tian Y, Xing J, Shi Y, Yuan E. Exploring the relationship between IGHMBP2 gene mutations and spinal muscular atrophy with respiratory distress type 1 and Charcot-Marie-Tooth disease type 2S: a systematic review. Front Neurosci 2023; 17:1252075. [PMID: 38046662 PMCID: PMC10690808 DOI: 10.3389/fnins.2023.1252075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 11/03/2023] [Indexed: 12/05/2023] Open
Abstract
Background IGHMBP2 is a crucial gene for the development and maintenance of the nervous system, especially in the survival of motor neurons. Mutations in this gene have been associated with spinal muscular atrophy with respiratory distress type 1 (SMARD1) and Charcot-Marie-Tooth disease type 2S (CMT2S). Methods We conducted a systematic literature search using the PubMed database to identify studies published up to April 1st, 2023, that investigated the association between IGHMBP2 mutations and SMARD1 or CMT2S. We compared the non-truncating mutations and truncating mutations of the IGHMBP2 gene and selected high-frequency mutations of the IGHMBP2 gene. Results We identified 52 articles that investigated the association between IGHMBP2 mutations and SMARD1/CMT2S. We found 6 hotspot mutations of the IGHMBP2 gene. The truncating mutations in trans were all associated with SMARD1. Conclusion This study provides evidence that the complete LOF mechanism of the IGHMBP2 gene defect may be an important cause of SMARD1.
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Affiliation(s)
- Yuan Tian
- Department of Clinical Laboratory, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Jinfang Xing
- Department of Clinical Laboratory, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Ying Shi
- Screening Center, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Enwu Yuan
- Department of Clinical Laboratory, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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Sierra-Delgado JA, Sinha-Ray S, Kaleem A, Ganjibakhsh M, Parvate M, Powers S, Zhang X, Likhite S, Meyer K. In Vitro Modeling as a Tool for Testing Therapeutics for Spinal Muscular Atrophy and IGHMBP2-Related Disorders. BIOLOGY 2023; 12:867. [PMID: 37372153 DOI: 10.3390/biology12060867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/08/2023] [Accepted: 06/12/2023] [Indexed: 06/29/2023]
Abstract
Spinal Muscular Atrophy (SMA) is the leading genetic cause of infant mortality. The most common form of SMA is caused by mutations in the SMN1 gene, located on 5q (SMA). On the other hand, mutations in IGHMBP2 lead to a large disease spectrum with no clear genotype-phenotype correlation, which includes Spinal Muscular Atrophy with Muscular Distress type 1 (SMARD1), an extremely rare form of SMA, and Charcot-Marie-Tooth 2S (CMT2S). We optimized a patient-derived in vitro model system that allows us to expand research on disease pathogenesis and gene function, as well as test the response to the AAV gene therapies we have translated to the clinic. We generated and characterized induced neurons (iN) from SMA and SMARD1/CMT2S patient cell lines. After establishing the lines, we treated the generated neurons with AAV9-mediated gene therapy (AAV9.SMN (Zolgensma) for SMA and AAV9.IGHMBP2 for IGHMBP2 disorders (NCT05152823)) to evaluate the response to treatment. The iNs of both diseases show a characteristic short neurite length and defects in neuronal conversion, which have been reported in the literature before with iPSC modeling. SMA iNs respond to treatment with AAV9.SMN in vitro, showing a partial rescue of the morphology phenotype. For SMARD1/CMT2S iNs, we were able to observe an improvement in the neurite length of neurons after the restoration of IGHMBP2 in all disease cell lines, albeit to a variable extent, with some lines showing better responses to treatment than others. Moreover, this protocol allowed us to classify a variant of uncertain significance on IGHMBP2 on a suspected SMARD1/CMT2S patient. This study will further the understanding of SMA, and SMARD1/CMT2S disease in particular, in the context of variable patient mutations, and might further the development of new treatments, which are urgently needed.
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Affiliation(s)
| | - Shrestha Sinha-Ray
- The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Abuzar Kaleem
- The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Meysam Ganjibakhsh
- The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Mohini Parvate
- The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Samantha Powers
- The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Xiaojin Zhang
- The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Shibi Likhite
- The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Kathrin Meyer
- The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
- College of Medicine, The Ohio State University, Columbus, OH 43205, USA
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