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Kask K, Tikker L, Ruisu K, Lulla S, Oja EM, Meier R, Raid R, Velling T, Tõnissoo T, Pooga M. Targeted deletion of RIC8A in mouse neural precursor cells interferes with the development of the brain, eyes, and muscles. Dev Neurobiol 2018; 78:374-390. [PMID: 29380551 DOI: 10.1002/dneu.22578] [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: 06/27/2017] [Revised: 01/18/2018] [Accepted: 01/18/2018] [Indexed: 11/11/2022]
Abstract
Autosomal recessive disorders such as Fukuyama congenital muscular dystrophy, Walker-Warburg syndrome, and the muscle-eye-brain disease are characterized by defects in the development of patient's brain, eyes, and skeletal muscles. These syndromes are accompanied by brain malformations like type II lissencephaly in the cerebral cortex with characteristic overmigrations of neurons through the breaches of the pial basement membrane. The signaling pathways activated by laminin receptors, dystroglycan and integrins, control the integrity of the basement membrane, and their malfunctioning may underlie the pathologies found in the rise of defects reminiscent of these syndromes. Similar defects in corticogenesis and neuromuscular disorders were found in mice when RIC8A was specifically removed from neural precursor cells. RIC8A regulates a subset of G-protein α subunits and in several model organisms, it has been reported to participate in the control of cell division, signaling, and migration. Here, we studied the role of RIC8A in the development of the brain, muscles, and eyes of the neural precursor-specific conditional Ric8a knockout mice. The absence of RIC8A severely affected the attachment and positioning of radial glial processes, Cajal-Retzius' cells, and the arachnoid trabeculae, and these mice displayed additional defects in the lens, skeletal muscles, and heart development. All the discovered defects might be linked to aberrancies in cell adhesion and migration, suggesting that RIC8A has a crucial role in the regulation of cell-extracellular matrix interactions and that its removal leads to the phenotype characteristic to type II lissencephaly-associated diseases. © 2018 Wiley Periodicals, Inc. Develop Neurobiol 78: 374-390, 2018.
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Affiliation(s)
- Keiu Kask
- Institute of Molecular and Cell Biology, University of Tartu, 23 Riia St, Tartu, 51010, Estonia
| | - Laura Tikker
- Department of Biosciences, University of Helsinki, P.O. Box 56, Viikinkaari 9, FIN-00014, Helsinki, Finland
| | - Katrin Ruisu
- Institute of Molecular and Cell Biology, University of Tartu, 23 Riia St, Tartu, 51010, Estonia
| | - Sirje Lulla
- Institute of Molecular and Cell Biology, University of Tartu, 23 Riia St, Tartu, 51010, Estonia
| | - Eva-Maria Oja
- Institute of Molecular and Cell Biology, University of Tartu, 23 Riia St, Tartu, 51010, Estonia
| | - Riho Meier
- Institute of Molecular and Cell Biology, University of Tartu, 23 Riia St, Tartu, 51010, Estonia
| | - Raivo Raid
- Institute of Molecular and Cell Biology, University of Tartu, 23 Riia St, Tartu, 51010, Estonia
| | - Teet Velling
- Institute of Molecular and Cell Biology, University of Tartu, 23 Riia St, Tartu, 51010, Estonia
| | - Tambet Tõnissoo
- Institute of Molecular and Cell Biology, University of Tartu, 23 Riia St, Tartu, 51010, Estonia
| | - Margus Pooga
- Institute of Molecular and Cell Biology, University of Tartu, 23 Riia St, Tartu, 51010, Estonia.,Institute of Technology, University of Tartu, Nooruse 1, Tartu, 50411, Estonia
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Cetin E, Cuisset JM, Tiffreau V, Vallée L, Hurtevent JF, Thevenon A. The value of electromyography in the aetiological diagnosis of hypotonia in infants and toddlers. Ann Phys Rehabil Med 2009; 52:546-55. [PMID: 19713169 DOI: 10.1016/j.rehab.2009.06.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Accepted: 06/23/2009] [Indexed: 11/27/2022]
Abstract
INTRODUCTION During the first two years of life, hypotonia may be the only symptom of a central or peripheral nervous system disorder. We propose to assess the sensitivity of electroneuromyography (ENMG) in the aetiological diagnosis of hypotonia of neuromuscular origin in infants and toddlers. METHOD This is a retrospective, single-centre study with revision of the files of the 37 children aged between zero and 24 months who, between 1994 and 2006, underwent an ENMG in the etiological approach of their hypotonia and had a final diagnosis of neuromuscular disease. RESULTS All the 13 patients with spinal muscular atrophy or Charcot Marie-Tooth disease displayed neurogenic alterations on the electromyography (EMG). Among the 24 children ultimately diagnosed with myopathies, five only displayed myogenic alterations when tested before the age of two. Sixteen had normal EMG results and three showed neurogenic alterations. DISCUSSION AND CONCLUSION In infants presenting with hypotonia, ENMG is useful for the diagnosis of peripheral neuropathy. Normal ENMG is relatively common for confirmed muscle disorders in infants whereas myogenic alterations seem more unusual, so that muscle biopsy appears unquestionable. In a few cases, early onset myopathies may present with a neurogenic ENMG pattern. Such a result should not invalidate the clinically presumed diagnosis of myopathy and would indicate on the contrary the need for a muscle biopsy.
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Affiliation(s)
- E Cetin
- Physical Medicine and Rehabilitation department, Lille University Hospital, André-Verhaghe street, 59037 Lille cedex, France
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A laminin-2, dystroglycan, utrophin axis is required for compartmentalization and elongation of myelin segments. J Neurosci 2009; 29:3908-19. [PMID: 19321787 DOI: 10.1523/jneurosci.5672-08.2009] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Animal and plant cells compartmentalize to perform morphogenetic functions. Compartmentalization of myelin-forming Schwann cells may favor elongation of myelin segments to the size required for efficient conduction of nerve impulses. Compartments in myelinated fibers were described by Ramón y Cajal and depend on periaxin, mutated in the hereditary neuropathy Charcot-Marie-Tooth disease type 4F (Charcot-Marie-Tooth 4F). Lack of periaxin in mice causes loss of compartments, formation of short myelin segments (internodes) and reduced nerve conduction velocity. How compartments are formed and maintained, and their relevance to human neuropathies is largely unknown. Here we show that formation of compartments around myelin is driven by the actin cytoskeleton, and maintained by actin and tubulin fences through linkage to the dystroglycan complex. Compartmentalization and establishment of correct internodal length requires the presence of glycosylated dystroglycan, utrophin and extracellular laminin-2/211. A neuropathic patient with reduced internodal length and nerve conduction velocity because of absence of laminin-2/211 (congenital muscular dystrophy 1A) also shows abnormal compartmentalization. These data link formation of compartments through a laminin2, dystroglycan, utrophin, actin axis to internodal length, and provide a common pathogenetic mechanism for two inherited human neuropathies. Other cell types may exploit dystroglycan complexes in similar fashions to create barriers and compartments.
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Matta APDC, Gonsalves MDCD. Merosin-positive congenital muscular dystrophy: neuroimaging findings. ARQUIVOS DE NEURO-PSIQUIATRIA 2007; 65:167-9. [PMID: 17420850 DOI: 10.1590/s0004-282x2007000100035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2006] [Accepted: 10/27/2006] [Indexed: 11/22/2022]
Abstract
Congenital muscle dystrophy (CMD) is a heterogeneous group of autosomal recessive myopathies. It is known that CMD may affect the central nervous system (CNS). Some authors have shown that merosin-negative CMD patients may have encephalic metabolic disturbances. In order to study metabolic changes within the brain, the authors performed a magnetic resonance spectroscopy (MRS) study in a 1-year-old girl with merosin-positive CMD (MP-CMD). MRS of brain demonstrated that NAA/Cr ratio was decreased (1.52), while Cho/Cr ratio was increased (1.78). These findings suggest that metabolic changes in CNS can also be found in patients with MP-CMD.
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Affiliation(s)
- André Palma da Cunha Matta
- Sarah Network of Hospitals for Rehabilitation, Praça Antonio Callado 175/106, 22793-084 Rio de Janeiro, RJ, Brazil.
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Quijano-Roy S, Renault F, Romero N, Guicheney P, Fardeau M, Estournet B. EMG and nerve conduction studies in children with congenital muscular dystrophy. Muscle Nerve 2004; 29:292-9. [PMID: 14755496 DOI: 10.1002/mus.10544] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Motor and sensory nerve conduction velocities (NCVs) and needle electromyography (EMG) results were reviewed in 26 children with different types of congenital muscular dystrophy (CMD), including patients with mutations in the genes LAMA2, FKRP, and COL6A2. In every patient, at least one EMG examination detected myopathic changes that were predominant in proximal muscles, although EMG performed at birth was normal in two patients. Brief bursts of high-frequency repetitive discharges were electrically elicited in four patients. Uniformly slowed motor NCVs without signs of denervation were observed in seven patients: five merosin-deficient, one merosin-positive, and one with unavailable merosin status. The merosin-deficient neuropathy also involved sensory nerves in three patients and worsened with age in two. In conclusion, myopathic EMG changes were typical and early findings in all types of CMD. An associated neuropathy was detected in most patients with merosin-deficient CMD, and also in a child with normal merosin expression.
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Affiliation(s)
- Susana Quijano-Roy
- Unité de Neurophysiologie, Hôpital d'Enfants Armand-Trousseau, 28 avenue Arnold Netter, 75571 Paris, France
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Triki C, Louhichi N, Méziou M, Choyakh F, Kéchaou MS, Jlidi R, Mhiri C, Fakhfakh F, Ayadi H. Merosin-deficient congenital muscular dystrophy with mental retardation and cerebellar cysts, unlinked to the LAMA2, FCMD, MEB and CMD1B loci, in three Tunisian patients. Neuromuscul Disord 2003; 13:4-12. [PMID: 12467726 DOI: 10.1016/s0960-8966(02)00188-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We report three Tunisian patients affected by congenital muscular dystrophy with mental retardation and cerebellar cysts on cranial magnetic resonance imaging. The clinical features were characterized by hypotonia at birth, joint contractures associated with severe psychomotor retardation, absence of speech, inability to walk in three patients, but calf hypertrophy was noted only in two patients. Brain magnetic resonance imaging showed several cerebellar cysts and vermis hypoplasia in all of the patients. Abnormality of the white matter was present in two patients. The pattern of gyration was normal in all cases. Serum creatine kinase was elevated in all three cases and their muscle biopsy showed dystrophic changes compatible with congenital muscular dystrophy. The immunohistochemical analysis of the skeletal muscle revealed partial merosin deficiency, more pronounced for the N-terminal antibody. Linkage analysis excluded congenital muscular dystrophy loci on chromosomes 6q22, 9q31, 1p32 and 1q42. These patients constituted a particular form of congenital muscular dystrophy with a combination of severe motor delay, mental retardation, partial merosin deficiency and cerebellar cysts. Two patients showed white matter abnormalities on magnetic resonance imaging and hypertrophy of the calves. These cases, in addition to those reported previously, confirmed the large phenotypic variability in the group of secondary merosin deficiency congenital muscular dystrophy.
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Affiliation(s)
- Chahnez Triki
- Department of Neurology, CHU. HabibBourguiba, 3029, Sfax, Tunisia.
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