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Vadla GP, Singh K, Lorson CL, Lorson MA. The contribution and therapeutic implications of IGHMBP2 mutations on IGHMBP2 biochemical activity and ABT1 association. Biochim Biophys Acta Mol Basis Dis 2024; 1870:167091. [PMID: 38403020 PMCID: PMC10999323 DOI: 10.1016/j.bbadis.2024.167091] [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: 11/16/2023] [Revised: 02/01/2024] [Accepted: 02/15/2024] [Indexed: 02/27/2024]
Abstract
Mutations within immunoglobulin mu DNA binding protein (IGHMBP2), an RNA-DNA helicase, result in SMA with respiratory distress type I (SMARD1) and Charcot Marie Tooth type 2S (CMT2S). The underlying biochemical mechanism of IGHMBP2 is unknown as well as the functional significance of IGHMBP2 mutations in disease severity. Here we report the biochemical mechanisms of IGHMBP2 disease-causing mutations D565N and H924Y, and their potential impact on therapeutic strategies. The IGHMBP2-D565N mutation has been identified in SMARD1 patients, while the IGHMBP2-H924Y mutation has been identified in CMT2S patients. For the first time, we demonstrate a correlation between the altered IGHMBP2 biochemical activity associated with the D565N and H924Y mutations and disease severity and pathology in patients and our Ighmbp2 mouse models. We show that IGHMBP2 mutations that alter the association with activator of basal transcription (ABT1) impact the ATPase and helicase activities of IGHMBP2 and the association with the 47S pre-rRNA 5' external transcribed spacer. We demonstrate that the D565N mutation impairs IGHMBP2 ATPase and helicase activities consistent with disease pathology. The H924Y mutation alters IGHMBP2 activity to a lesser extent while maintaining association with ABT1. In the context of the compound heterozygous patient, we demonstrate that the total biochemical activity associated with IGHMBP2-D565N and IGHMBP2-H924Y proteins is improved over IGHMBP2-D565N alone. Importantly, we demonstrate that the efficacy of therapeutic applications may vary based on the underlying IGHMBP2 mutations and the relative biochemical activity of the mutant IGHMBP2 protein.
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Affiliation(s)
- Gangadhar P Vadla
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA; Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Kamal Singh
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA; Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Christian L Lorson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA; Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Monique A Lorson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA; Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.
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2
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Smith CE, Lorson MA, Ricardez Hernandez SM, Al Rawi Z, Mao J, Marquez J, Villalón E, Keilholz AN, Smith CL, Garro-Kacher MO, Morcos T, Davis DJ, Bryda EC, Nichols NL, Lorson CL. The Ighmbp2D564N mouse model is the first SMARD1 model to demonstrate respiratory defects. Hum Mol Genet 2022; 31:1293-1307. [PMID: 34726235 PMCID: PMC9029233 DOI: 10.1093/hmg/ddab317] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/30/2021] [Accepted: 10/26/2021] [Indexed: 11/12/2022] Open
Abstract
Spinal muscular atrophy with respiratory distress type I (SMARD1) is a neurodegenerative disease defined by respiratory distress, muscle atrophy and sensory and autonomic nervous system defects. SMARD1 is a result of mutations within the IGHMBP2 gene. We have generated six Ighmbp2 mouse models based on patient-derived mutations that result in SMARD1 and/or Charcot-Marie Tooth Type 2 (CMT2S). Here we describe the characterization of one of these models, Ighmbp2D564N (human D565N). The Ighmbp2D564N/D564N mouse model mimics important aspects of the SMARD1 disease phenotype, including motor neuron degeneration and muscle atrophy. Ighmbp2D564N/D564N is the first SMARD1 mouse model to demonstrate respiratory defects based on quantified plethysmography analyses. SMARD1 disease phenotypes, including the respiratory defects, are significantly diminished by intracerebroventricular (ICV) injection of ssAAV9-IGHMBP2 and the extent of phenotypic restoration is dose-dependent. Collectively, this model provides important biological insight into SMARD1 disease development.
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Affiliation(s)
- Caley E Smith
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Monique A Lorson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Sara M Ricardez Hernandez
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Zayd Al Rawi
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Jiude Mao
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Jose Marquez
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Eric Villalón
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Amy N Keilholz
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Catherine L Smith
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Mona O Garro-Kacher
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Toni Morcos
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Daniel J Davis
- Animal Modeling Core, University of Missouri, Columbia, MO 65211, USA
| | - Elizabeth C Bryda
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
- Animal Modeling Core, University of Missouri, Columbia, MO 65211, USA
| | - Nicole L Nichols
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Christian L Lorson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
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3
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Shababi M, Smith CE, Ricardez Hernandez SM, Marquez J, Al Rawi Z, Villalón E, Farris KD, Garro-Kacher MO, Lorson CL. Defining the optimal dose and therapeutic window in SMA with respiratory distress type I model mice, FVB/NJ- Ighmpb2 nmd-2J. Mol Ther Methods Clin Dev 2021; 23:23-32. [PMID: 34553000 PMCID: PMC8426477 DOI: 10.1016/j.omtm.2021.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 07/30/2021] [Indexed: 11/23/2022]
Abstract
Spinal muscular atrophy with respiratory distress type 1 (SMARD1) is an autosomal recessive disorder that develops in infancy and arises from mutation of the immunoglobulin helicase μ-binding protein 2 (IGHMBP2) gene. Whereas IGHMBP2 is ubiquitously expressed, loss or reduction of function leads to alpha motor neuron loss and skeletal muscle atrophy. We previously developed a gene therapy strategy for SMARD1 using a single-stranded AAV9-IGHMBP2 vector and compared two different delivery methods in a validated SMARD1 mouse model. An important question in the field relates to the temporal requirements for this or any potential treatment. To examine the therapeutic window, we utilized our recently developed SMARD1 model, FVB/NJ-Ighmpb2 nmd-2J , to deliver AAV9-IGHMBP2 at four different time points starting at post-natal day 2 (P2) through P8. At each time point, significant improvements were observed in survival, weight gain, and motor function. Similarly, treatment improved important hallmarks of disease, including motor unit pathology. Whereas improvements were more pronounced in the early-treatment groups, even the later-treatment groups displayed significant phenotypic improvements. This work suggests that an effective gene therapy strategy could provide benefits to pre-symptomatic and early-symptomatic individuals, thereby expanding the potential therapeutic window for SMARD1.
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Affiliation(s)
- Monir Shababi
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Caley E. Smith
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | | | - Jose Marquez
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Zayd Al Rawi
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Eric Villalón
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - K. David Farris
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Mona O. Garro-Kacher
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Christian L. Lorson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
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4
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Shababi M, Smith CE, Kacher M, Alrawi Z, Villalon E, Davis D, Bryda EC, Lorson CL. Development of a novel severe mouse model of spinal muscular atrophy with respiratory distress type 1: FVB-nmd. Biochem Biophys Res Commun 2019; 520:341-346. [PMID: 31604525 PMCID: PMC6936219 DOI: 10.1016/j.bbrc.2019.10.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 10/02/2019] [Indexed: 11/29/2022]
Abstract
Spinal Muscular Atrophy with Respiratory Distress type 1 (SMARD1) is an autosomal recessive disease that develops early during infancy. The gene responsible for disease development is immunoglobulin helicase μ-binding protein 2 (IGHMBP2). IGHMBP2 is a ubiquitously expressed gene but its mutation results in the loss of alpha-motor neurons and subsequent muscle atrophy initially of distal muscles. The current SMARD1 mouse model arose from a spontaneous mutation originally referred to as neuromuscular degeneration (nmd). The nmd mice have the C57BL/6 genetic background and contain an A to G mutation in intron 4 of the endogenous Ighmbp2 gene. This mutation causes aberrant splicing, resulting in only 20-25% of full-length functional protein. Several congenital conditions including hydrocephalus are common in the C57BL/6 background, consistent with our previous observations when developing a gene therapy approach for SMARD1. Additionally, a modifier allele exists on chromosome 13 in nmd mice that can partially suppress the phenotype, resulting in some animals that have extended life spans (up to 200 days). To eliminate the intrinsic complications of the C57BL/6 background and the variation in survival due to the genetic modifier effect, we created a new SMARD1 mouse model that contains the same intron 4 mutation in Ighmbp2 as nmd mice but is now on a FVB congenic background. FVB-nmd are consistently more severe than the original nmd mice with respect to survival, weigh and motor function. The relatively short life span (18-21 days) of FVB-nmd mice allows us to monitor therapeutic efficacy for a variety of novel therapeutics in a timely manner without the complication of the small percentage of longer-lived animals that were observed in our colony of nmd mice.
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Affiliation(s)
- Monir Shababi
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA,Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri, USA
| | - Caley E. Smith
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri, USA,Department of Molecular Microbiology and Immunology, University of Missouri School of Medicine, Columbia, Missouri, USA
| | - Mona Kacher
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA,Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri, USA
| | - Zayd Alrawi
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri, USA
| | - Eric Villalon
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA,Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri, USA
| | - Daniel Davis
- Animal Modeling Core, University of Missouri, Columbia, Missouri, USA
| | - Elizabeth C. Bryda
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA,Animal Modeling Core, University of Missouri, Columbia, Missouri, USA
| | - Christian L. Lorson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA,Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri, USA,Department of Molecular Microbiology and Immunology, University of Missouri School of Medicine, Columbia, Missouri, USA
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5
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Villalón E, Lee NN, Marquez J, Lorson CL. Muscle fiber-type selective propensity to pathology in the nmd mouse model of SMARD1. Biochem Biophys Res Commun 2019; 516:313-319. [PMID: 31256932 DOI: 10.1016/j.bbrc.2019.06.117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 06/21/2019] [Indexed: 12/01/2022]
Abstract
Spinal muscular atrophy with respiratory distress type 1 (SMARD1) is an autosomal recessive disease that causes distal limb muscle atrophy, due to motor neuron degeneration. Similar to other motor neuron diseases, SMARD1 shows differential vulnerability to denervation in various muscle groups, which is recapitulated in the nmd mouse, a model of SMARD1. In multiple neurodegenerative disease models, transcriptomic analysis has identified differentially expressed genes between vulnerable motor neuron populations, but the mechanism leading to susceptibility is largely unknown. To investigate if denervation vulnerability is linked to intrinsic muscle properties, we analyzed muscle fiber-type composition in muscles from motor units that show different degrees of denervation in nmd mice: gastrocnemius, tibialis anterior (TA), and extensor digitorum longus (EDL). Our results revealed that denervation vulnerability correlated with atrophy and loss of MyHC-IIb and MyHC-IIx muscle fiber types. Interestingly, increased vulnerability also correlated with an increased abundance of MyHC-I and MyHC-IIa muscle fibers. These results indicated that MyHC-IIx muscle fibers are the most vulnerable to denervation, followed by MyHC-IIb muscle fibers. Moreover, our data indicate that type MyHC-IIa and MyHC-IIb muscle fibers show resistance to denervation and compensate for the loss of MyHC-IIx and MyHC-IIb muscle fibers in the most vulnerable muscles. Taken together these results provide a basis for the selective vulnerability to denervation of specific muscles in nmd mice and identifies new targets for potential therapeutic intervention.
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Affiliation(s)
- Eric Villalón
- Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA; Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, 65211, USA
| | - Naomi N Lee
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, 65211, USA
| | - Jose Marquez
- Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA; Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, 65211, USA
| | - Christian L Lorson
- Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA; Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, 65211, USA.
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6
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Villalón E, Shababi M, Kline R, Lorson ZC, Florea KM, Lorson CL. Selective vulnerability in neuronal populations in nmd/SMARD1 mice. Hum Mol Genet 2019; 27:679-690. [PMID: 29272405 DOI: 10.1093/hmg/ddx434] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 12/15/2017] [Indexed: 12/12/2022] Open
Abstract
Spinal muscular atrophy with respiratory distress type 1 (SMARD1) is an autosomal recessive motor neuron disease causing distal limb muscle atrophy that progresses proximally and is accompanied by diaphragmatic paralysis. Neuromuscular junction (NMJ) alterations have been reported in muscles of SMARD1 model mice, known as nmd mice, with varying degrees of severity, suggesting that different muscles are specifically and selectively resistant or susceptible to denervation. To evaluate the extent of NMJ pathology in a broad range of muscles, a panel of axial and appendicular muscles were isolated and immunostained from nmd mice. These analyses revealed that selective distal appendage muscles were highly vulnerable to denervation. Susceptibility to pathology was not limited to NMJ alterations, but included defects in myelination within those neurons innervating susceptible muscles. Interestingly, end plate fragmentation was present within all muscles independent of the extent of NMJ alterations, suggesting that end plate fragmentation is an early hallmark of SMARD1 pathogenesis. Expressing the full-length IGHMBP2 cDNA using an adeno-associated virus (AAV9) significantly decreased all aspects of muscle and nerve disease pathology. These results shed new light onto the pathogenesis of SMARD1 by identifying specific motor units that are resistant and susceptible to neurodegeneration in an important model of SMARD1.
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Affiliation(s)
- Eric Villalón
- Department of Veterinary Pathobiology, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.,Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Monir Shababi
- Department of Veterinary Pathobiology, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.,Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Rachel Kline
- Department of Veterinary Pathobiology, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.,Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Zachary C Lorson
- Department of Veterinary Pathobiology, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.,Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Kyra M Florea
- Department of Veterinary Pathobiology, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.,Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Christian L Lorson
- Department of Veterinary Pathobiology, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.,Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
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7
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Belter L, Cook SF, Crawford TO, Jarecki J, Jones CC, Kissel JT, Schroth M, Hobby K. An overview of the Cure SMA membership database: Highlights of key demographic and clinical characteristics of SMA members. J Neuromuscul Dis 2018; 5:167-176. [PMID: 29614694 PMCID: PMC6004903 DOI: 10.3233/jnd-170292] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Background: The Cure SMA database is one of the largest patient reported databases for people affected with SMA. Objective: The purpose of this study was to examine a subset of affected SMA persons with types I, II, and III from a patient reported database. Methods: Individuals with SMA were selected from the database using a date of first contact to Cure SMA between 2010 and 2016. Data analyzed included age at diagnosis, number of weeks from SMA diagnosis to contacting Cure SMA, and geographic distribution of individuals. Results: A total of 1,966 individuals with SMA were included in the analysis. Of these individuals, 51.9% had type I, 32.3% had type II, and 15.8% had type III. The average age of diagnosis for type I patients was 5.2 months, 22.1 months for type II, and 97.8 months for type III. From published incidence, about 59.0% of affected individuals in the US are registered in the Cure SMA database. Conclusions: The Cure SMA database is a unique and robust source of patient reported data that informs on the burden of illness and supports the development of new therapeutic modalities.
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Affiliation(s)
| | | | | | | | | | | | - Mary Schroth
- Cure SMA, Elk Grove Village, IL, USA.,University of Wisconsin, Madison, WI, USA
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8
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Shababi M, Villalón E, Kaifer KA, DeMarco V, Lorson CL. A Direct Comparison of IV and ICV Delivery Methods for Gene Replacement Therapy in a Mouse Model of SMARD1. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2018; 10:348-360. [PMID: 30202772 PMCID: PMC6127875 DOI: 10.1016/j.omtm.2018.08.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Accepted: 08/13/2018] [Indexed: 01/22/2023]
Abstract
Spinal muscular atrophy with respiratory distress type 1 (SMARD1) is an infantile autosomal recessive disease caused by the loss of the ubiquitously expressed IGHMBP2 gene. SMARD1 causes degeneration of alpha-motor neurons, resulting in distal muscle weakness, diaphragm paralysis, and respiratory malfunction. We have reported that delivery of a low dose of AAV9-IGHMBP2 to the CNS results in a significant rescue of the SMARD1 mouse model (nmd). To examine how a delivery route can impact efficacy, a direct comparison of intravenous (IV) and intracerebroventricular (ICV) delivery of AAV9-IGHMBP2 was performed. Using a low-dose, both IV and ICV delivery routes led to a significant extension in survival and increased body weight. Conversely, only ICV-treated animals demonstrated improvements in the hindlimb muscle, neuromuscular junction, and motor function. The hindlimb phenotype of IV-treated mice resembled the untreated nmd mice. We investigated whether the increased survival of IV-treated nmd mice was the result of a positive impact on the cardiac function. Our results revealed that cardiac function and pathology were similarly improved in IV- and ICV-treated mice. We concluded that while IV delivery of a low dose does not improve the hindlimb phenotype and motor function, partial restoration of cardiac performance is sufficient to significantly extend survival.
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Affiliation(s)
- Monir Shababi
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA.,Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | - Eric Villalón
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA.,Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | - Kevin A Kaifer
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA.,Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | - Vince DeMarco
- Department of Medicine, Division of Endocrinology, Diabetes and Cardiovascular Center, University of Missouri, Columbia, MO, USA.,Department of Medical Pharmacology and Physiology, School of Medicine, University of Missouri, Columbia, MO, USA.,Research Service, Harry S. Truman Memorial Veterans Hospital, University of Missouri, Columbia, MO, USA
| | - Christian L Lorson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA.,Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
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9
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Sarnat HB. Academic productivity after retirement in pediatric neurology and neuropathology. Neurology 2018; 91:36-40. [PMID: 29802168 DOI: 10.1212/wnl.0000000000005743] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 03/20/2018] [Indexed: 12/30/2022] Open
Abstract
Many academic neurologists and neuropathologists who retire at the peak of their careers continue to be productive in research and teaching, enhanced by years of experience and mature perspective. The early 20th-century model of institutions depending upon the generosity of such individuals to donate their time and efforts without proper recognition or compensation, despite the service, prestige, and recognition they bring to their institutions, should be reconsidered in the early 21st century in the context of fairness, honesty, dignity, and increased longevity. University pensions do not distinguish retirees who continue to contribute from those who stop working. This essay represents the author's personal reflections and experience, reinforced by similar thoughts and encouragement by numerous distinguished colleagues named at the end of the text. Funding of stipends for active emeritus professors lacks precedent but should be sought.
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Affiliation(s)
- Harvey B Sarnat
- From the Departments of Paediatrics, Pathology and Laboratory Medicine (Neuropathology), and Clinical Neurosciences, University of Calgary Cumming School of Medicine and Alberta Children's Hospital Research Institute, Calgary, Canada.
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10
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Rescue of a Mouse Model of Spinal Muscular Atrophy With Respiratory Distress Type 1 by AAV9-IGHMBP2 Is Dose Dependent. Mol Ther 2016; 24:855-66. [PMID: 26860981 DOI: 10.1038/mt.2016.33] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 01/17/2016] [Indexed: 01/07/2023] Open
Abstract
Spinal muscular atrophy with respiratory distress type 1 (SMARD1) is an autosomal recessive disease occurring during childhood. The gene responsible for disease development is a ubiquitously expressed protein, IGHMBP2. Mutations in IGHMBP2 result in the loss of α-motor neurons leading to muscle atrophy in the distal limbs accompanied by respiratory complications. Although genetically and clinically distinct, proximal SMA is also caused by the loss of a ubiquitously expressed gene (SMN). Significant preclinical success has been achieved in proximal SMA using viral-based gene replacement strategies. We leveraged the technologies employed in SMA to demonstrate gene replacement efficacy in an SMARD1 animal model. Intracerebroventricular (ICV) injection of single-stranded AAV9 expressing the full-length cDNA of IGHMBP2 in a low dose led to a significant level of rescue in treated SMARD1 animals. Consistent with drastically increased survival, weight gain, and strength, the rescued animals demonstrated a significant improvement in muscle, NMJ, motor neurons, and axonal pathology. In addition, increased levels of IGHMBP2 in lumbar motor neurons verified the efficacy of the virus to transduce the target tissues. Our results indicate that AAV9-based gene replacement is a viable strategy for SMARD1, although dosing effects and potential negative impacts of high dose and ICV injection should be thoroughly investigated.
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11
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Li X, Hu Z, Liu L, Xie Y, Zhan Y, Zi X, Wang J, Wu L, Xia K, Tang B, Zhang R. A SIGMAR1 splice-site mutation causes distal hereditary motor neuropathy. Neurology 2015; 84:2430-7. [PMID: 26078401 DOI: 10.1212/wnl.0000000000001680] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 03/06/2015] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To identify the underlying genetic cause in a consanguineous Chinese family segregating distal hereditary motor neuropathy (dHMN) in an autosomal recessive pattern. METHODS We used whole-exome sequencing and homozygosity mapping to detect the genetic variant in 2 affected individuals of the consanguineous Chinese family with dHMN. RNA analysis of peripheral blood leukocytes and immunofluorescence and immunoblotting of stable cell lines were performed to support the pathogenicity of the identified mutation. RESULTS We identified 3 shared novel homozygous variants in 3 shared homozygous regions of the affected individuals. Sequencing of these 3 variants in family members revealed the c.151+1G>T mutation in SIGMAR1 gene, which located in homozygous region spanning approximately 5.3 Mb at chromosome 9p13.1-p13.3, segregated with the dHMN phenotype. The mutation causes an alternative splicing event and generates a transcript variant with an in-frame deletion of 60 base pairs in exon 1 (c.92_151del), and results in an internally shortened protein σ1R(31_50del). The proteasomal inhibitor treatment increased the intracellular amount of σ1R(31_50del) and led to the formation of nuclear aggregates. Stable expressing σ1R(31_50del) induced endoplasmic reticulum stress and enhanced apoptosis. CONCLUSION The homozygous c.151+1G>T mutation in SIGMAR1 caused a novel form of autosomal recessive dHMN in a Chinese consanguineous family. Endoplasmic reticulum stress may have a role in the pathogenesis of dHMN.
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Affiliation(s)
- Xiaobo Li
- From the Department of Neurology, the Third Xiangya Hospital (X.L., L.L., Y.X., X.Z., R.Z.), State Key Laboratory of Medical Genetics (Z.H., J.W., K.X., B.T.), and Department of Physiology, Xiangya School of Medicine (X.L., L.W.), Central South University, Changsha, PR China
| | - Zhengmao Hu
- From the Department of Neurology, the Third Xiangya Hospital (X.L., L.L., Y.X., X.Z., R.Z.), State Key Laboratory of Medical Genetics (Z.H., J.W., K.X., B.T.), and Department of Physiology, Xiangya School of Medicine (X.L., L.W.), Central South University, Changsha, PR China
| | - Lei Liu
- From the Department of Neurology, the Third Xiangya Hospital (X.L., L.L., Y.X., X.Z., R.Z.), State Key Laboratory of Medical Genetics (Z.H., J.W., K.X., B.T.), and Department of Physiology, Xiangya School of Medicine (X.L., L.W.), Central South University, Changsha, PR China
| | - Yongzhi Xie
- From the Department of Neurology, the Third Xiangya Hospital (X.L., L.L., Y.X., X.Z., R.Z.), State Key Laboratory of Medical Genetics (Z.H., J.W., K.X., B.T.), and Department of Physiology, Xiangya School of Medicine (X.L., L.W.), Central South University, Changsha, PR China
| | - Yajing Zhan
- From the Department of Neurology, the Third Xiangya Hospital (X.L., L.L., Y.X., X.Z., R.Z.), State Key Laboratory of Medical Genetics (Z.H., J.W., K.X., B.T.), and Department of Physiology, Xiangya School of Medicine (X.L., L.W.), Central South University, Changsha, PR China
| | - Xiaohong Zi
- From the Department of Neurology, the Third Xiangya Hospital (X.L., L.L., Y.X., X.Z., R.Z.), State Key Laboratory of Medical Genetics (Z.H., J.W., K.X., B.T.), and Department of Physiology, Xiangya School of Medicine (X.L., L.W.), Central South University, Changsha, PR China
| | - Junling Wang
- From the Department of Neurology, the Third Xiangya Hospital (X.L., L.L., Y.X., X.Z., R.Z.), State Key Laboratory of Medical Genetics (Z.H., J.W., K.X., B.T.), and Department of Physiology, Xiangya School of Medicine (X.L., L.W.), Central South University, Changsha, PR China
| | - Lixiang Wu
- From the Department of Neurology, the Third Xiangya Hospital (X.L., L.L., Y.X., X.Z., R.Z.), State Key Laboratory of Medical Genetics (Z.H., J.W., K.X., B.T.), and Department of Physiology, Xiangya School of Medicine (X.L., L.W.), Central South University, Changsha, PR China
| | - Kun Xia
- From the Department of Neurology, the Third Xiangya Hospital (X.L., L.L., Y.X., X.Z., R.Z.), State Key Laboratory of Medical Genetics (Z.H., J.W., K.X., B.T.), and Department of Physiology, Xiangya School of Medicine (X.L., L.W.), Central South University, Changsha, PR China
| | - Beisha Tang
- From the Department of Neurology, the Third Xiangya Hospital (X.L., L.L., Y.X., X.Z., R.Z.), State Key Laboratory of Medical Genetics (Z.H., J.W., K.X., B.T.), and Department of Physiology, Xiangya School of Medicine (X.L., L.W.), Central South University, Changsha, PR China
| | - Ruxu Zhang
- From the Department of Neurology, the Third Xiangya Hospital (X.L., L.L., Y.X., X.Z., R.Z.), State Key Laboratory of Medical Genetics (Z.H., J.W., K.X., B.T.), and Department of Physiology, Xiangya School of Medicine (X.L., L.W.), Central South University, Changsha, PR China.
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Porro F, Rinchetti P, Magri F, Riboldi G, Nizzardo M, Simone C, Zanetta C, Faravelli I, Corti S. The wide spectrum of clinical phenotypes of spinal muscular atrophy with respiratory distress type 1: A systematic review. J Neurol Sci 2014; 346:35-42. [DOI: 10.1016/j.jns.2014.09.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 09/05/2014] [Accepted: 09/08/2014] [Indexed: 12/13/2022]
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13
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Gathwala G, Silayach J, Bhakhari BK, Narwal V. Very severe spinal muscular atrophy: Type 0 with Dandy-Walker variant. J Pediatr Neurosci 2014; 9:55-6. [PMID: 24891907 PMCID: PMC4040036 DOI: 10.4103/1817-1745.131488] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease characterized by degeneration of alpha motor neurons in the spinal cord, resulting in progressive proximal muscle weakness and paralysis. In addition to the three classical SMA types, a new form known as type 0 with intrauterine onset, profound hypotonia and a progressive and early fatal course has been described. Herein we report a case of type 0 SMA with a Dandy Walker variant anomaly, which has not hitherto been reported in the world literature.
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Affiliation(s)
- Geeta Gathwala
- Department of Pediatrics, The Division of Neonatal Services, Pandit Bhagwat Dayal Sharma Post Graduate Institute of Medical Sciences, Rohtak, Haryana, India
| | - Joginder Silayach
- Department of Pediatrics, The Division of Neonatal Services, Pandit Bhagwat Dayal Sharma Post Graduate Institute of Medical Sciences, Rohtak, Haryana, India
| | - Bhanu Kiran Bhakhari
- Department of Pediatrics, The Division of Neonatal Services, Pandit Bhagwat Dayal Sharma Post Graduate Institute of Medical Sciences, Rohtak, Haryana, India
| | - Varun Narwal
- Department of Pediatrics, The Division of Neonatal Services, Pandit Bhagwat Dayal Sharma Post Graduate Institute of Medical Sciences, Rohtak, Haryana, India
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14
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Peeters K, Litvinenko I, Asselbergh B, Almeida-Souza L, Chamova T, Geuens T, Ydens E, Zimoń M, Irobi J, De Vriendt E, De Winter V, Ooms T, Timmerman V, Tournev I, Jordanova A. Molecular defects in the motor adaptor BICD2 cause proximal spinal muscular atrophy with autosomal-dominant inheritance. Am J Hum Genet 2013; 92:955-64. [PMID: 23664119 PMCID: PMC3675262 DOI: 10.1016/j.ajhg.2013.04.013] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 04/16/2013] [Accepted: 04/16/2013] [Indexed: 12/14/2022] Open
Abstract
The most common form of spinal muscular atrophy (SMA) is a recessive disorder caused by deleterious SMN1 mutations in 5q13, whereas the genetic etiologies of non-5q SMA are very heterogeneous and largely remain to be elucidated. In a Bulgarian family affected by autosomal-dominant proximal SMA, we performed genome-wide linkage analysis and whole-exome sequencing and found a heterozygous de novo c.320C>T (p.Ser107Leu) mutation in bicaudal D homolog 2 (Drosophila) (BICD2). Further analysis of BICD2 in a cohort of 119 individuals with non-5q SMA identified a second de novo BICD2 mutation, c.2321A>G (p.Glu774Gly), in a simplex case. Detailed clinical and electrophysiological investigations revealed that both families are affected by a very similar disease course, characterized by early childhood onset, predominant involvement of lower extremities, and very slow disease progression. The amino acid substitutions are located in two interaction domains of BICD2, an adaptor protein linking the dynein molecular motor with its cargo. Our immunoprecipitation and localization experiments in HeLa and SH-SY5Y cells and affected individuals' lymphoblasts demonstrated that p.Ser107Leu causes increased dynein binding and thus leads to accumulation of BICD2 at the microtubule-organizing complex and Golgi fragmentation. In addition, the altered protein had a reduced colocalization with RAB6A, a regulator of vesicle trafficking between the Golgi and the endoplasmic reticulum. The interaction between p.Glu744Gly altered BICD2 and RAB6A was impaired, which also led to their reduced colocalization. Our study identifies BICD2 mutations as a cause of non-5q linked SMA and highlights the importance of dynein-mediated motility in motor neuron function in humans.
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Affiliation(s)
- Kristien Peeters
- Molecular Neurogenomics Group, Department of Molecular Genetics, VIB, Antwerp 2610, Belgium
- Neurogenetics Laboratory, Institute Born-Bunge, University of Antwerp, Antwerp 2610, Belgium
| | - Ivan Litvinenko
- Clinic of Child Neurology, Department of Pediatrics, Medical University-Sofia, Sofia 1000, Bulgaria
| | - Bob Asselbergh
- Neurogenetics Laboratory, Institute Born-Bunge, University of Antwerp, Antwerp 2610, Belgium
- Centralized Service Facility, Department of Molecular Genetics, VIB, Antwerp 2610, Belgium
| | - Leonardo Almeida-Souza
- Neurogenetics Laboratory, Institute Born-Bunge, University of Antwerp, Antwerp 2610, Belgium
- Peripheral Neuropathy Group, Department of Molecular Genetics, VIB, Antwerp 2610, Belgium
| | - Teodora Chamova
- Department of Neurology, Medical University-Sofia, Sofia 1000, Bulgaria
| | - Thomas Geuens
- Neurogenetics Laboratory, Institute Born-Bunge, University of Antwerp, Antwerp 2610, Belgium
- Peripheral Neuropathy Group, Department of Molecular Genetics, VIB, Antwerp 2610, Belgium
| | - Elke Ydens
- Neurogenetics Laboratory, Institute Born-Bunge, University of Antwerp, Antwerp 2610, Belgium
- Peripheral Neuropathy Group, Department of Molecular Genetics, VIB, Antwerp 2610, Belgium
| | - Magdalena Zimoń
- Molecular Neurogenomics Group, Department of Molecular Genetics, VIB, Antwerp 2610, Belgium
- Neurogenetics Laboratory, Institute Born-Bunge, University of Antwerp, Antwerp 2610, Belgium
| | - Joy Irobi
- Centralized Service Facility, Department of Molecular Genetics, VIB, Antwerp 2610, Belgium
| | - Els De Vriendt
- Molecular Neurogenomics Group, Department of Molecular Genetics, VIB, Antwerp 2610, Belgium
- Neurogenetics Laboratory, Institute Born-Bunge, University of Antwerp, Antwerp 2610, Belgium
| | - Vicky De Winter
- Neurogenetics Laboratory, Institute Born-Bunge, University of Antwerp, Antwerp 2610, Belgium
- Peripheral Neuropathy Group, Department of Molecular Genetics, VIB, Antwerp 2610, Belgium
| | - Tinne Ooms
- Molecular Neurogenomics Group, Department of Molecular Genetics, VIB, Antwerp 2610, Belgium
- Neurogenetics Laboratory, Institute Born-Bunge, University of Antwerp, Antwerp 2610, Belgium
| | - Vincent Timmerman
- Neurogenetics Laboratory, Institute Born-Bunge, University of Antwerp, Antwerp 2610, Belgium
- Peripheral Neuropathy Group, Department of Molecular Genetics, VIB, Antwerp 2610, Belgium
| | - Ivailo Tournev
- Department of Neurology, Medical University-Sofia, Sofia 1000, Bulgaria
- Department of Cognitive Science and Psychology, New Bulgarian University, Sofia 1618, Bulgaria
| | - Albena Jordanova
- Molecular Neurogenomics Group, Department of Molecular Genetics, VIB, Antwerp 2610, Belgium
- Neurogenetics Laboratory, Institute Born-Bunge, University of Antwerp, Antwerp 2610, Belgium
- Department of Medical Chemistry and Biochemistry, Molecular Medicine Center, Medical University-Sofia, Sofia 1431, Bulgaria
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Parman Y, Battaloğlu E. Recessively transmitted predominantly motor neuropathies. HANDBOOK OF CLINICAL NEUROLOGY 2013; 115:847-861. [PMID: 23931818 DOI: 10.1016/b978-0-444-52902-2.00048-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Recessively transmitted predominantly motor neuropathies are rare and show a severe phenotype. They are frequently observed in populations with a high rate of consanguineous marriages. At least 15 genes and six loci have been found to be associated with autosomal recessive CMT (AR-CMT) and X-linked CMT (AR-CMTX) and also distal hereditary motor neuronopathy (AR-dHMN). These disorders are genetically heterogeneous but the clinical phenotype is relatively homogeneous. Distal muscle weakness and atrophy predominating in the lower extremities, diminished or absent deep tendon reflexes, distal sensory loss, and pes cavus are the main clinical features of this disorder with occasional cranial nerve involvement. Although genetic diagnosis of some of subtypes of AR-CMT are now available, rapid advances in the molecular genetics and cell biology show a great complexity. Animal models for the most common subtypes of human AR-CMT disease provide clues for understanding the pathogenesis of CMT and also help to reveal possible treatment strategies of inherited neuropathies. This chapter highlights the clinical features and the recent genetic and biological findings in these disorders based on the current classification.
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Affiliation(s)
- Yeşim Parman
- Department of Neurology, Istanbul University, Istanbul Medical Faculty, Istanbul, Turkey.
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16
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Abstract
The inherited neuropathies are a clinically and genetically heterogeneous group of disorders in which there have been rapid advances in the last two decades. Molecular genetic testing is now an integral part of the evaluation of patients with inherited neuropathies. In this chapter we describe the genes responsible for the primary inherited neuropathies. We briefly discuss the clinical phenotype of each of the known inherited neuropathy subgroups, describe algorithms for molecular genetic testing of affected patients and discuss genetic counseling. The basic principles of careful phenotyping, documenting an accurate family history, and testing the available genes in an appropriate manner should identify the vast majority of individuals with CMT1 and many of those with CMT2. In this chapter we also describe the current methods of genetic testing. As advances are made in molecular genetic technologies and improvements are made in bioinformatics, it is likely that the current time-consuming methods of DNA sequencing will give way to quicker and more efficient high-throughput methods, which are briefly discussed here.
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17
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Rouleau GA. Addendum to 'Recent advances in the genetics of distal hereditary motor neuropathy give insight to a disease mechanism involving copper homeostasis that may extend to other motor neuron disorders'. Clin Genet 2011; 79:601-3. [PMID: 21542836 DOI: 10.1111/j.1399-0004.2011.01665.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- G A Rouleau
- Centre of Excellence in Neuromics, CHUM Research Center, and Department of Medicine, Université de Montréal, Montréal, Québec, Canada.
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18
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Devic P, Petiot P. [Distal hereditary motor neuropathy]. Rev Neurol (Paris) 2011; 167:781-90. [PMID: 21529868 DOI: 10.1016/j.neurol.2011.03.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 02/15/2011] [Accepted: 03/08/2011] [Indexed: 10/18/2022]
Abstract
INTRODUCTION Distal hereditary motor neuropathy (dHMN), also known as spinal muscular atrophy, represents a group of clinically and genetically heterogeneous diseases caused by degenerations of spinal motor neurons and leading to distal muscle weakness and wasting. Nerve conduction studies reveal a pure motor axonopathy and needle examination shows chronic denervation. STATE OF ART dHMN were initially subdivided into seven subtypes according to mode of inheritance, age at onset, and clinical evolution. Recent studies have shown that these subtypes are still heterogeneous at the molecular genetic level and novel clinical and genetic entities have been characterized. To date, mutations in 11 different genes have been identified for autosomal-dominant, autosomal-recessive, and X-linked recessive dHMN. Most of the genes encode protein involved in housekeeping functions, endosomal trafficking, axonal transport, translation synthesis, RNA processing, oxidative stress response and apoptosis. PERSPECTIVES The pathophysiological mechanisms underlying dHMN seem to be related to the "length-dependent" death of motor neurons of the anterior horn of the spinal cord, likely because their large axons have higher metabolic requirements for maintenance. CONCLUSION dHMN remain heterogeneous at the clinical and molecular genetic level. The molecular pathomechanisms explaining why mutations in these ubiquitously expressed housekeeping genes result in the selective involvement of spinal motor neurons remain to be unravelled.
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Affiliation(s)
- P Devic
- Service de Neurologie Fonctionnelle et d'Épileptologie, Hôpital Neurologique Pierre-Wertheimer, 59, Boulevard Pinel, 69003 Lyon, France.
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19
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Merner ND, Dion PA, Rouleau GA. Recent advances in the genetics of distal hereditary motor neuropathy give insight to a disease mechanism involving copper homeostasis that may extend to other motor neuron disorders. Clin Genet 2010; 79:23-34. [DOI: 10.1111/j.1399-0004.2010.01591.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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20
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Harms MB, Allred P, Gardner R, Fernandes Filho JA, Florence J, Pestronk A, Al-Lozi M, Baloh RH. Dominant spinal muscular atrophy with lower extremity predominance: linkage to 14q32. Neurology 2010; 75:539-46. [PMID: 20697106 DOI: 10.1212/wnl.0b013e3181ec800c] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVE Spinal muscular atrophies (SMAs) are hereditary disorders characterized by weakness from degeneration of spinal motor neurons. Although most SMA cases with proximal weakness are recessively inherited, rare families with dominant inheritance have been reported. We aimed to clinically, pathologically, and genetically characterize a large North American family with an autosomal dominant proximal SMA. METHODS Affected family members underwent clinical and electrophysiologic evaluation. Twenty family members were genotyped on high-density genome-wide SNP arrays and linkage analysis was performed. RESULTS Ten affected individuals (ages 7-58 years) showed prominent quadriceps atrophy, moderate to severe weakness of quadriceps and hip abductors, and milder degrees of weakness in other leg muscles. Upper extremity strength and sensation was normal. Leg weakness was evident from early childhood and was static or very slowly progressive. Electrophysiology and muscle biopsies were consistent with chronic denervation. SNP-based linkage analysis showed a maximum 2-point lod score of 5.10 (theta = 0.00) at rs17679127 on 14q32. A disease-associated haplotype spanning from 114 cM to the 14q telomere was identified. A single recombination narrowed the minimal genomic interval to Chr14: 100,220,765-106,368,585. No segregating copy number variations were found within the disease interval. CONCLUSIONS We describe a family with an early onset, autosomal dominant, proximal SMA with a distinctive phenotype: symptoms are limited to the legs and there is notable selectivity for the quadriceps. We demonstrate linkage to a 6.1-Mb interval on 14q32 and propose calling this disorder spinal muscular atrophy-lower extremity, dominant.
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Affiliation(s)
- M B Harms
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
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21
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Muglia M, Magariello A, Citrigno L, Passamonti L, Sprovieri T, Conforti FL, Mazzei R, Patitucci A, Gabriele AL, Ungaro C, Bellesi M, Quattrone A. A novel locus for dHMN with pyramidal features maps to chromosome 4q34.3-q35.2. Clin Genet 2008; 73:486-91. [PMID: 18336586 DOI: 10.1111/j.1399-0004.2008.00969.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The distal hereditary motor neuropathy (dHMN) is a rare genetically and clinically heterogeneous disorder characterized by weakness and wasting of distal limb muscles in absence of overt sensory abnormalities. Recently, pyramidal signs have been also described in some patients with dominant or recessive dHMN, and two different loci have been identified in families affected by dHMN complicated with pyramidal dysfunction. We investigated an Italian family affected by an autosomal dominant dHMN complicated by pyramidal signs in order to map a new gene locus. The disease maps to a novel locus in a 26-cM region flanked by D4S1552 and D4S2930 on chromosome 4q34.3-35.2. Three candidate genes (SNX25, CASP3 and TUBB4Q) located in the critical region were screened for the presence of mutations by heteroduplex analysis. No mutations have been detected in the analyzed genes. In conclusion, the new private genetic locus we reported further confirms the wide heterogeneity of dHMN.
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Affiliation(s)
- M Muglia
- Institute of Neurological Sciences, National Research Council, Mangone, Cosenza, Italy.
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Barisic N, Claeys KG, Sirotković-Skerlev M, Löfgren A, Nelis E, De Jonghe P, Timmerman V. Charcot-Marie-Tooth disease: a clinico-genetic confrontation. Ann Hum Genet 2008; 72:416-41. [PMID: 18215208 DOI: 10.1111/j.1469-1809.2007.00412.x] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Charcot-Marie-Tooth disease (CMT) is the most common neuromuscular disorder. It represents a group of clinically and genetically heterogeneous inherited neuropathies. Here, we review the results of molecular genetic investigations and the clinical and neurophysiological features of the different CMT subtypes. The products of genes associated with CMT phenotypes are important for the neuronal structure maintenance, axonal transport, nerve signal transduction and functions related to the cellular integrity. Identifying the molecular basis of CMT and studying the relevant genes and their functions is important to understand the pathophysiological mechanisms of these neurodegenerative disorders, and the processes involved in the normal development and function of the peripheral nervous system. The results of molecular genetic investigations have impact on the appropriate diagnosis, genetic counselling and possible new therapeutic options for CMT patients.
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Affiliation(s)
- N Barisic
- Department of Pediatrics, Zagreb University Medical School, Zagreb, Croatia.
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Talbot K, Davies KE. Chapter 7 Spinal muscular atrophies and hereditary motor neuropathies. HANDBOOK OF CLINICAL NEUROLOGY 2007; 82:141-153. [PMID: 18808892 DOI: 10.1016/s0072-9752(07)80010-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- Kevin Talbot
- Department of Human Anatomy and Genetics, University of Oxford, UK; Department of Clinical Neurology, University of Oxford, UK
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Tsirikos AI, Baker AD. Spinal muscular atrophy: Classification, aetiology, and treatment of spinal deformity in children and adolescents. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.cuor.2006.09.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Irobi J, Dierick I, Jordanova A, Claeys KG, De Jonghe P, Timmerman V. Unraveling the genetics of distal hereditary motor neuronopathies. Neuromolecular Med 2006; 8:131-46. [PMID: 16775372 DOI: 10.1385/nmm:8:1-2:131] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 02/02/2023]
Abstract
The hereditary motor neuronopathies (HMN [MIM 158590]) are a heterogeneous group of disorders characterized by an exclusive involvement of the motor part of the peripheral nervous system. They are usually subdivided in proximal HMN, i.e., the classical spinal muscular atrophy syndromes and distal hereditary motor neuronopathies (distal HMN) that clinically resemble Charcot-Marie-Tooth syndromes. In this review, we concentrate on distal HMN. The distal HMN are clinically and genetically heterogeneous and were initially subdivided in seven subtypes according to mode of inheritance, age at onset, and clinical evolution. Recent studies have shown that these subtypes are still heterogeneous at the molecular genetic level and novel clinical and genetic entities have been delineated. Since the introduction of positional cloning, 13 chromosomal loci and seven disease-associated genes have been identified for autosomal-dominant, autosomal-recessive, and X-linked recessive distal HMN. Most of the genes involved encode protein with housekeeping functions, such as RNA processing, translation synthesis, stress response, apoptosis, and others code for proteins involved in retrograde survival. Motor neurons of the anterior horn of the spinal cord seems to be vulnerable to defects in these housekeeping proteins, likely because their large axons have higher metabolic requirements for maintenance, transport over long distances and precise connectivity. Understanding the molecular pathomechanisms for mutations in these genes that are ubiquitous expressed will help unravel the neuronal mechanisms that underlie motor neuropathies leading to denervation of distal limb muscles, and might generate new insights for future therapeutic strategies.
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Affiliation(s)
- Joy Irobi
- Peripheral Neuropathy Group, Department of Molecular Genetics, Flanders Interuniversity Institute for Biotechnology, University of Antwerp, Antwerpen, Belgium
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Monani UR. Spinal muscular atrophy: a deficiency in a ubiquitous protein; a motor neuron-specific disease. Neuron 2006; 48:885-96. [PMID: 16364894 DOI: 10.1016/j.neuron.2005.12.001] [Citation(s) in RCA: 233] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disease in humans and the most common genetic cause of infant mortality. The disease results in motor neuron loss and skeletal muscle atrophy. Despite a range of disease phenotypes, SMA is caused by mutations in a single gene, the Survival of Motor Neuron 1 (SMN1) gene. Recent advances have shed light on functions of the protein product of this gene and the pathophysiology of the disease, yet, fundamental questions remain. This review attempts to highlight some of the recent advances made in the understanding of the disease and how loss of the ubiquitously expressed survival of motor neurons (SMN) protein results in the SMA phenotype. Answers to some of the questions raised may ultimately result in a viable treatment for SMA.
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Affiliation(s)
- Umrao R Monani
- Department of Neurology, Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, New York 10032, USA.
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Striano P, Boccella P, Sarappa C, Striano S. Spinal muscular atrophy and progressive myoclonic epilepsy: one case report and characteristics of the epileptic syndrome. Seizure 2004; 13:582-6. [PMID: 15519918 DOI: 10.1016/j.seizure.2004.01.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION Spinal muscular atrophies (SMAs) are a group of degenerative diseases primarily affecting the anterior horn cells of the spinal cord and motor cells of cranial nerve nuclei. Even if the clinical picture is mainly dominated by the diffuse muscular atrophy, in some cases, patients may show associated, atypical clinical features ("SMA plus"). In particular, the association of SMA and progressive myoclonic epilepsy (PME) has been rarely described. CASE REPORT We present the clinical and electrophysiological data of a boy with childhood-onset SMA associated with PME and reviewed cases of the literature. CONCLUSION The association of SMA with PME may constitute a separate and, probably, genetically independent syndrome with unique clinical and electroencephalographic findings or, at least, a variant of a neurodegenerative or metabolic disease, due to yet unknown causes.
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Affiliation(s)
- Pasquale Striano
- Department of Neurological Sciences, Epilepsy Center, Federico II University, Via Pansini 5, 80131 Naples, Italy
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Maddatu TP, Garvey SM, Shroeder DG, Hampton TG, Cox GA. Transgenic rescue of neurogenic atrophy in the nmd mouse reveals a role for Ighmbp2 in dilated cardiomyopathy. Hum Mol Genet 2004; 13:1105-15. [PMID: 15069027 PMCID: PMC1350377 DOI: 10.1093/hmg/ddh129] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Immunoglobulin mu binding protein 2 (IGHMBP2) is a DNA/RNA helicase with a putative role in transcriptional regulation and splicing. A recessive mutation of the Ighmbp2 gene in neuromuscular degeneration (nmd) mice causes progressive neurogenic atrophy of limb muscles. Affected mice show significant loss of motor neurons with large caliber axons and a moderate reduction of neurons with small caliber axons in the ventral nerve roots of the spinal cord. To investigate the role of Ighmbp2 in the pathogenesis of neuromuscular degeneration, we generated two independent lines of transgenic mice expressing the full-length Ighmbp2 cDNA specifically in neurons. Histopathological evaluation of L4 ventral nerve roots revealed that transgenic expression of the Ighmbp2 cDNA prevented primary motor neuron degeneration, while restoring the normal axonal morphology and density in nmd mice. A similar neuronal improvement is found in mutant mice carrying the CAST/EiJ-derived modifier of nmd (Mnm(C)). Intriguingly, both the transgenic and modified nmd mice went on to develop a previously unobserved cardiac and skeletal myopathy. Necropsy of nmd mice in end-stage heart failure revealed a primary dilated cardiomyopathy with secondary respiratory failure that was confirmed by in vivo ECG and echocardiographic measures. Our results suggest that reduced levels of IGHMBP2 in nmd mice compromise the integrity and function not only of motor neurons but also of skeletal and cardiac myocytes. These findings highlight the important role of IGHMBP2 in the maintenance and survival of these terminally differentiated cell types.
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Affiliation(s)
| | | | | | - Thomas G. Hampton
- Cardiovascular Division, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02146
| | - Gregory A. Cox
- The Jackson Laboratory 600 Main Street, Bar Harbor ME 046093
- *To whom correspondence should be addressed. Address correspondence to: Gregory A. Cox, The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609 USA, Telephone: (207) 288-6502, FAX: (207) 288-6073, E-mail:
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Viollet L, Zarhrate M, Maystadt I, Estournet-Mathiaut B, Barois A, Desguerre I, Mayer M, Chabrol B, LeHeup B, Cusin V, Billette De Villemeur T, Bonneau D, Saugier-Veber P, Touzery-De Villepin A, Delaubier A, Kaplan J, Jeanpierre M, Feingold J, Munnich A. Refined genetic mapping of autosomal recessive chronic distal spinal muscular atrophy to chromosome 11q13.3 and evidence of linkage disequilibrium in European families. Eur J Hum Genet 2004; 12:483-8. [PMID: 15054395 DOI: 10.1038/sj.ejhg.5201177] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Chronic distal spinal muscular atrophy (Chronic DSMA, MIM (*)607088) is a rare autosomal recessive disorder characterized by a progressive motor weakness and muscular atrophy, predominating in the distal parts of the limbs. A form of Chronic DSMA gene has been previously mapped to chromosome 11q13 in the 10.3 cM interval defined by loci D11S1889 and D11S1321. By linkage analysis in 12 European Chronic DSMA families, we showed that a disease gene maps to chromosome 11q13.3 (Z(max)=6.66 at theta=0.00 at the DSM4 locus) and suggested that this condition is genetically homogeneous. Recombination events allowed us to reduce the genetic interval to a 2.6 cM region, telomeric to the IGHMBP2 gene, excluding this gene as the disease causing gene in Chronic DSMA. Moreover, partial linkage disequilibrium was found between three rare alleles at loci D11S1369, DSM4 and D11S4184 and the mutant chromosome in European patients. Analysis of the markers at these loci strongly suggests that most Chronic DSMA chromosomes are derived from a single ancestor. Refinement of the Chronic DSMA locus will hopefully allow to test candidate genes and lead to identification of the disease-causing mutations.
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Affiliation(s)
- Louis Viollet
- Unité de Recherches sur les Handicaps Génétiques de l'Enfant, INSERM U393. Hôpital Necker Enfants Malades, 149 rue de Sèvres, 75743 Paris Cedex 15, France.
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Spinal muscular atrophies reveal motor neuron vulnerability to defects in ribonucleoprotein handling. Curr Opin Neurol 2003. [DOI: 10.1097/00019052-200310000-00005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Zerres K, Rudnik-Schöneborn S. 93rd ENMC international workshop: non-5q-spinal muscular atrophies (SMA) - clinical picture (6-8 April 2001, Naarden, The Netherlands). Neuromuscul Disord 2003; 13:179-83. [PMID: 12565918 DOI: 10.1016/s0960-8966(02)00211-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
MESH Headings
- Animals
- Arthrogryposis/complications
- Arthrogryposis/genetics
- Bulbar Palsy, Progressive/complications
- Bulbar Palsy, Progressive/genetics
- Chromosome Disorders/complications
- Chromosome Disorders/genetics
- Chromosome Mapping
- Chromosomes, Human, Pair 5
- Disease Models, Animal
- Epilepsies, Myoclonic/complications
- Epilepsies, Myoclonic/genetics
- Genetic Linkage
- Humans
- Infant
- Infant, Newborn
- Muscular Atrophy, Spinal/classification
- Muscular Atrophy, Spinal/complications
- Muscular Atrophy, Spinal/congenital
- Muscular Atrophy, Spinal/genetics
- Phenotype
- Respiratory Distress Syndrome, Newborn/etiology
- Respiratory Distress Syndrome, Newborn/genetics
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Affiliation(s)
- Klaus Zerres
- Institute for Human Genetics, University of Technology, Pauwelsstrasse 30, D-52074, Aachen, Germany.
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Chapter 16 Spinal Muscular Atrophy. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s1877-3419(09)70117-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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