51
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Whitman MC, Engle EC. Ocular congenital cranial dysinnervation disorders (CCDDs): insights into axon growth and guidance. Hum Mol Genet 2017; 26:R37-R44. [PMID: 28459979 DOI: 10.1093/hmg/ddx168] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 04/27/2017] [Indexed: 12/11/2022] Open
Abstract
Unraveling the genetics of the paralytic strabismus syndromes known as congenital cranial dysinnervation disorders (CCDDs) is both informing physicians and their patients and broadening our understanding of development of the ocular motor system. Genetic mutations underlying ocular CCDDs alter either motor neuron specification or motor nerve development, and highlight the importance of modulations of cell signaling, cytoskeletal transport, and microtubule dynamics for axon growth and guidance. Here we review recent advances in our understanding of two CCDDs, congenital fibrosis of the extraocular muscles (CFEOM) and Duane retraction syndrome (DRS), and discuss what they have taught us about mechanisms of axon guidance and selective vulnerability. CFEOM presents with congenital ptosis and restricted eye movements, and can be caused by heterozygous missense mutations in the kinesin motor protein KIF21A or in the β-tubulin isotypes TUBB3 or TUBB2B. CFEOM-causing mutations in these genes alter protein function and result in axon growth and guidance defects. DRS presents with inability to abduct one or both eyes. It can be caused by decreased function of several transcription factors critical for abducens motor neuron identity, including MAFB, or by heterozygous missense mutations in CHN1, which encodes α2-chimaerin, a Rac-GAP GTPase that affects cytoskeletal dynamics. Examination of the orbital innervation in mice lacking Mafb has established that the stereotypical misinnervation of the lateral rectus by fibers of the oculomotor nerve in DRS is secondary to absence of the abducens nerve. Studies of a CHN1 mouse model have begun to elucidate mechanisms of selective vulnerability in the nervous system.
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Affiliation(s)
- Mary C Whitman
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA.,Department of Ophthalmology, Boston Children's Hospital, Boston, MA 02115, USA.,Department of Ophthalmology, Harvard Medical School, Boston, MA 02115, USA
| | - Elizabeth C Engle
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA.,Department of Ophthalmology, Boston Children's Hospital, Boston, MA 02115, USA.,Department of Ophthalmology, Harvard Medical School, Boston, MA 02115, USA.,Department of Neurology, Boston Children's Hospital, Boston, MA 02115, USA.,Department of Neurology, Harvard Medical School, Boston, MA 02115, USA.,Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
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52
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An exome sequencing study of Moebius syndrome including atypical cases reveals an individual with CFEOM3A and a TUBB3 mutation. Cold Spring Harb Mol Case Stud 2017; 3:a000984. [PMID: 28299356 PMCID: PMC5334472 DOI: 10.1101/mcs.a000984] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Moebius syndrome is characterized by congenital unilateral or bilateral facial and abducens nerve palsies (sixth and seventh cranial nerves) causing facial weakness, feeding difficulties, and restricted ocular movements. Abnormalities of the chest wall such as Poland anomaly and variable limb defects are frequently associated with this syndrome. Most cases are isolated; however, rare families with autosomal dominant transmission with incomplete penetrance and variable expressivity have been described. The genetic basis of this condition remains unknown. In a cohort study of nine individuals suspected to have Moebius syndrome (six typical, three atypical), we performed whole-exome sequencing to try to identify a commonly mutated gene. Although no such gene was identified and we did not find mutations in PLXND1 and REV3L, we found a de novo heterozygous mutation, p.E410K, in the gene encoding tubulin beta 3 class III (TUBB3), in an individual with atypical Moebius syndrome. This individual was diagnosed with near-complete ophthalmoplegia, agenesis of the corpus callosum, and absence of the septum pellucidum. No substantial limb abnormalities were noted. Mutations in TUBB3 have been associated with complex cortical dysplasia and other brain malformations and congenital fibrosis of extraocular muscles type 3A (CFEOM3A). Our report highlights the overlap of genetic etiology and clinical differences between CFEOM and Moebius syndrome and describes our approach to identifying candidate genes for typical and atypical Moebius syndrome.
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53
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Withdrawn: Discovering Genes Essential to the Hypothalamic Regulation of Human Reproduction Using a Human Disease Model: Adjusting to Life in the "-Omics" Era. Endocr Rev 2017. [PMID: 27454361 DOI: 10.1210/er.2015-1045.2016.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The neuroendocrine regulation of reproduction is an intricate process requiring the exquisite coordination of an assortment of cellular networks, all converging on the GnRH neurons. These neurons have a complex life history, migrating mainly from the olfactory placode into the hypothalamus, where GnRH is secreted and acts as the master regulator of the hypothalamic-pituitary-gonadal axis. Much of what we know about the biology of the GnRH neurons has been aided by discoveries made using the human disease model of isolated GnRH deficiency (IGD), a family of rare Mendelian disorders that share a common failure of secretion and/or action of GnRH causing hypogonadotropic hypogonadism. Over the last 30 years, research groups around the world have been investigating the genetic basis of IGD using different strategies based on complex cases that harbor structural abnormalities or single pleiotropic genes, endogamous pedigrees, candidate gene approaches as well as pathway gene analyses. Although such traditional approaches, based on well-validated tools, have been critical to establish the field, new strategies, such as next-generation sequencing, are now providing speed and robustness, but also revealing a surprising number of variants in known IGD genes in both patients and healthy controls. Thus, before the field moves forward with new genetic tools and continues discovery efforts, we must reassess what we know about IGD genetics and prepare to hold our work to a different standard. The purpose of this review is to: 1) look back at the strategies used to discover the "known" genes implicated in the rare forms of IGD; 2) examine the strengths and weaknesses of the methodologies used to validate genetic variation; 3)substantiate the role of known genes in the pathophysiology of the disease; and 4) project forward as we embark upon a widening use of these new and powerful technologies for gene discovery. (Endocrine Reviews 36: 603-621, 2015).
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54
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Rossor AM, Carr AS, Devine H, Chandrashekar H, Pelayo-Negro AL, Pareyson D, Shy ME, Scherer SS, Reilly MM. Peripheral neuropathy in complex inherited diseases: an approach to diagnosis. J Neurol Neurosurg Psychiatry 2017; 88:846-863. [PMID: 28794150 DOI: 10.1136/jnnp-2016-313960] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 03/07/2017] [Accepted: 03/08/2017] [Indexed: 12/14/2022]
Abstract
Peripheral neuropathy is a common finding in patients with complex inherited neurological diseases and may be subclinical or a major component of the phenotype. This review aims to provide a clinical approach to the diagnosis of this complex group of patients by addressing key questions including the predominant neurological syndrome associated with the neuropathy, for example, spasticity, the type of neuropathy and the other neurological and non-neurological features of the syndrome. Priority is given to the diagnosis of treatable conditions. Using this approach, we associated neuropathy with one of three major syndromic categories: (1) ataxia, (2) spasticity and (3) global neurodevelopmental impairment. Syndromes that do not fall easily into one of these three categories can be grouped according to the predominant system involved in addition to the neuropathy, for example, cardiomyopathy and neuropathy. We also include a separate category of complex inherited relapsing neuropathy syndromes, some of which may mimic Guillain-Barré syndrome, as many will have a metabolic aetiology and be potentially treatable.
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Affiliation(s)
- Alexander M Rossor
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK
| | - Aisling S Carr
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK
| | - Helen Devine
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK
| | - Hoskote Chandrashekar
- Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, London, UK
| | - Ana Lara Pelayo-Negro
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK
| | - Davide Pareyson
- Unit of Neurological Rare Diseases of Adulthood, Carlo Besta Neurological Institute IRCCS Foundation, Milan, Italy
| | - Michael E Shy
- Department of Neurology, University of Iowa, Iowa City, USA
| | - Steven S Scherer
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Mary M Reilly
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK
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55
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Ejaz R, Lionel AC, Blaser S, Walker S, Scherer SW, Babul-Hirji R, Marshall CR, Stavropoulos DJ, Chitayat D. De novo pathogenic variant in TUBB2A presenting with arthrogryposis multiplex congenita, brain abnormalities, and severe developmental delay. Am J Med Genet A 2017; 173:2725-2730. [PMID: 28840640 DOI: 10.1002/ajmg.a.38352] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 05/21/2017] [Accepted: 06/15/2017] [Indexed: 12/29/2022]
Abstract
Disorders of brain formation can occur from pathogenic variants in various alpha and beta tubulin genes. Heterozygous pathogenic variants in the beta tubulin isotype A gene, TUBB2A, have been recently implicated in brain malformations, seizures, and developmental delay. Limited information is known regarding the phenotypic spectrum associated with pathogenic variants in this gene given the rarity of the condition. We report the sixth individual with a de novo heterozygous TUBB2A pathogenic variant, who presented with a severe neurological phenotype along with unique features of arthrogryposis multiplex congenita, optic nerve hypoplasia, dysmorphic facial features, and vocal cord paralysis, thereby expanding the gene-related phenotype.
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Affiliation(s)
- Resham Ejaz
- Division of Clinical and Metabolic Genetics, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Anath C Lionel
- The Centre for Applied Genomics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Susan Blaser
- Division of Neuroradiology, Department of Diagnostic Imaging, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Susan Walker
- The Centre for Applied Genomics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Stephen W Scherer
- The Centre for Applied Genomics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.,McLaughlin Centre and Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Riyana Babul-Hirji
- Division of Clinical and Metabolic Genetics, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Christian R Marshall
- The Centre for Applied Genomics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.,Genome Diagnostics, Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Dimitri J Stavropoulos
- Genome Diagnostics, Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - David Chitayat
- Division of Clinical and Metabolic Genetics, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.,The Prenatal Diagnosis and Medical Genetics Program, Department of Obstetrics and Gynecology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
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56
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Fazeli W, Herkenrath P, Stiller B, Neugebauer A, Fricke J, Lang-Roth R, Nürnberg G, Thoenes M, Becker J, Altmüller J, Volk AE, Kubisch C, Heller R. A TUBB6 mutation is associated with autosomal dominant non-progressive congenital facial palsy, bilateral ptosis and velopharyngeal dysfunction. Hum Mol Genet 2017; 26:4055-4066. [DOI: 10.1093/hmg/ddx296] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 07/23/2017] [Indexed: 01/06/2023] Open
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57
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Parker AL, Teo WS, McCarroll JA, Kavallaris M. An Emerging Role for Tubulin Isotypes in Modulating Cancer Biology and Chemotherapy Resistance. Int J Mol Sci 2017; 18:ijms18071434. [PMID: 28677634 PMCID: PMC5535925 DOI: 10.3390/ijms18071434] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 06/24/2017] [Accepted: 06/27/2017] [Indexed: 12/19/2022] Open
Abstract
Tubulin proteins, as components of the microtubule cytoskeleton perform critical cellular functions throughout all phases of the cell cycle. Altered tubulin isotype composition of microtubules is emerging as a feature of aggressive and treatment refractory cancers. Emerging evidence highlighting a role for tubulin isotypes in differentially influencing microtubule behaviour and broader functional networks within cells is illuminating a complex role for tubulin isotypes regulating cancer biology and chemotherapy resistance. This review focuses on the role of different tubulin isotypes in microtubule dynamics as well as in oncogenic changes that provide a survival or proliferative advantage to cancer cells within the tumour microenvironment and during metastatic processes. Consideration of the role of tubulin isotypes beyond their structural function will be essential to improving the current clinical use of tubulin-targeted chemotherapy agents and informing the development of more effective cancer therapies.
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Affiliation(s)
- Amelia L Parker
- Tumour Biology and Targeting, Children's Cancer Institute, Lowy Cancer Research Centre, University of New South Wales, Sydney, NSW 2031, Australia.
- Australian Centre for NanoMedicine, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Wee Siang Teo
- Tumour Biology and Targeting, Children's Cancer Institute, Lowy Cancer Research Centre, University of New South Wales, Sydney, NSW 2031, Australia.
- Australian Centre for NanoMedicine, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Joshua A McCarroll
- Tumour Biology and Targeting, Children's Cancer Institute, Lowy Cancer Research Centre, University of New South Wales, Sydney, NSW 2031, Australia.
- Australian Centre for NanoMedicine, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Maria Kavallaris
- Tumour Biology and Targeting, Children's Cancer Institute, Lowy Cancer Research Centre, University of New South Wales, Sydney, NSW 2031, Australia.
- Australian Centre for NanoMedicine, ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of New South Wales, Sydney, NSW 2052, Australia.
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58
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Desikan RS, Barkovich AJ. Malformations of cortical development. Ann Neurol 2016; 80:797-810. [PMID: 27862206 PMCID: PMC5177533 DOI: 10.1002/ana.24793] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 09/26/2016] [Accepted: 09/26/2016] [Indexed: 01/05/2023]
Abstract
Malformations of cortical development (MCDs) compose a diverse range of disorders that are common causes of neurodevelopmental delay and epilepsy. With improved imaging and genetic methodologies, the underlying molecular and pathobiological characteristics of several MCDs have been recently elucidated. In this review, we discuss genetic and molecular alterations that disrupt normal cortical development, with emphasis on recent discoveries, and provide detailed radiological features of the most common and important MCDs. Ann Neurol 2016;80:797-810.
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Affiliation(s)
- Rahul S. Desikan
- Neuroradiology Section, Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA
| | - A. James Barkovich
- Neuroradiology Section, Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA
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59
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Congenital cranial dysinnervation disorders. Int Ophthalmol 2016; 37:1369-1381. [PMID: 27837354 DOI: 10.1007/s10792-016-0388-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 10/31/2016] [Indexed: 12/13/2022]
Abstract
The European Neuromuscular Centre (ENMC) derived the term Congenital Cranial Dysinnervation Disorders in 2002 at an international workshop for a group of congenital neuromuscular diseases. CCDDs are congenital, non-progressive ophthalmoplegia with restriction of globe movement in one or more fields of gaze. This group of sporadic and familial strabismus syndromes was initially referred to as the 'congenital fibrosis syndromes' because it was assumed that the primary pathologic process starts in the muscles of eye motility. Over the last few decades, evidence has accumulated to support that the primary pathologic process of these disorders is neuropathic rather than myopathic. This is believed that for normal development of extra ocular muscles and for preservation of muscle fiber anatomy, normal intra-uterine development of the innervation to these muscles is essential. Congenital dysinnervation to these EOMs can lead to abnormal muscle structure depending upon the stage and the extent of such innervational defects. Over last few years new genes responsible for CCDD have been identified, permitting a better understanding of associated phenotypes, which can further lead to better classification of these disorders. Introduction of high-resolution MRI has led to detailed study of cranial nerves courses and muscles supplied by them. Thus, due to better understanding of pathophysiology and genetics of CCDDs, various treatment modalities can be developed to ensure good ocular alignment and better quality of life for patients suffering from the same.
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60
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McKay VH, Touil LL, Jenkins D, Fattah AY. Managing the child with a diagnosis of Moebius syndrome: more than meets the eye. Arch Dis Child 2016; 101:843-6. [PMID: 26868039 DOI: 10.1136/archdischild-2015-310043] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 01/23/2016] [Indexed: 11/03/2022]
Abstract
Moebius syndrome (MBS) is a congenital, non-progressive facial and abducens nerve palsy in the presence of full vertical gaze and may be associated with limb abnormalities and craniofacial dysmorphisms. MBS is now defined as a disorder of rhombencephalic maldevelopment and recent gene discoveries have shown this to be a dominant disorder in a subset of patients. Accurate diagnosis and management by a multidisciplinary team with expertise in congenital facial palsy is paramount.
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Affiliation(s)
- Victoria H McKay
- Department of Clinical Genetics, Cheshire and Merseyside Regional Clinical Genetics Service, Liverpool Women's NHS Foundation Trust, Liverpool, UK
| | - Leila L Touil
- Regional Paediatric Burns and Plastic Surgery Service, Alder Hey Children's NHS Foundation Trust, Liverpool, UK
| | - Dagan Jenkins
- Clinical and Molecular Genetics Units, UCL Institute of Child Health, London, UK
| | - Adel Y Fattah
- Regional Paediatric Burns and Plastic Surgery Service, Alder Hey Children's NHS Foundation Trust, Liverpool, UK
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61
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Fukumura S, Kato M, Kawamura K, Tsuzuki A, Tsutsumi H. A Mutation in the Tubulin-Encoding TUBB3 Gene Causes Complex Cortical Malformations and Unilateral Hypohidrosis. Child Neurol Open 2016; 3:2329048X16665758. [PMID: 28503613 PMCID: PMC5417280 DOI: 10.1177/2329048x16665758] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 07/18/2016] [Accepted: 07/24/2016] [Indexed: 01/03/2023] Open
Abstract
Recent studies have emphasized the association between tubulin gene mutations and developmental abnormalities of the cortex. In this study, the authors identified a mutation in the tubulin-encoding class III β-tubulin (TUBB3) gene in a 4-year-old boy presenting with brain abnormalities and unilateral hypohidrosis. The patient showed a left internal strabismus, moderate developmental delay, and congenital hypohidrosis of the right side of the body. Magnetic resonance imaging disclosed gyral disorganization mainly in the left perisylvian region, dysmorphic and hypertrophic basal ganglia with fusion between the putamen and caudate nucleus without affecting the anterior limb of the internal capsule, and moderate hypoplasia of the right brain stem and cerebellum. Diffusion tensor imaging studies revealed disorganization of the pyramidal fibers. The amplitude of the sympathetic skin response was low in the right arm, which led to a diagnosis of focal autonomic neuropathy. Sequencing the TUBB3 gene revealed a de novo missense mutation, c.862G>A (p.E288K).
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Affiliation(s)
- Shinobu Fukumura
- Department of Pediatrics, School of Medicine, Sapporo Medical University, Sapporo, Japan
| | - Mitsuhiro Kato
- Department of Pediatrics, Yamagata University, Yamagata, Japan.,Department of Pediatrics, School of Medicine, Showa University, Shinagawa, Japan
| | - Kentaro Kawamura
- Department of Pediatrics, School of Medicine, Sapporo Medical University, Sapporo, Japan
| | - Akiko Tsuzuki
- Department of Rehabilitation, Hokkaido Medical Center for Child Health and Rehabilitation, Sapporo, Japan
| | - Hiroyuki Tsutsumi
- Department of Pediatrics, School of Medicine, Sapporo Medical University, Sapporo, Japan
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62
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Mutch CA, Poduri A, Sahin M, Barry B, Walsh CA, Barkovich AJ. Disorders of Microtubule Function in Neurons: Imaging Correlates. AJNR Am J Neuroradiol 2016; 37:528-35. [PMID: 26564436 DOI: 10.3174/ajnr.a4552] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 07/07/2015] [Indexed: 12/28/2022]
Abstract
BACKGROUND AND PURPOSE A number of recent studies have described malformations of cortical development with mutations of components of microtubules and microtubule-associated proteins. Despite examinations of a large number of MRIs, good phenotype-genotype correlations have been elusive. Additionally, most of these studies focused exclusively on cerebral cortical findings. The purpose of this study was to characterize imaging findings associated with disorders of microtubule function. MATERIALS AND METHODS MRIs from 18 patients with confirmed tubulin mutations (8 TUBA1A, 5 TUBB2B, and 5 TUBB3) and 15 patients with known mutations of the genes encoding microtubule-associated proteins (5 LIS1, 4 DCX, and 6 DYNC1H1) were carefully visually analyzed and compared. Specific note was made of the cortical gyral pattern, basal ganglia, and white matter to assess internal capsular size, cortical thickness, ventricular and cisternal size, and the size and contours of the brain stem, cerebellar hemispheres and vermis, and the corpus callosum of patients with tubulin and microtubule-associated protein gene mutations. Results were determined by unanimous consensus of the authors. RESULTS All patients had abnormal findings on MR imaging. A large number of patients with tubulin gene mutations were found to have multiple cortical and subcortical abnormalities, including microcephaly, ventriculomegaly, abnormal gyral and sulcal patterns (termed "dysgyria"), a small or absent corpus callosum, and a small pons. All patients with microtubule-associated protein mutations also had abnormal cerebral cortices (predominantly pachygyria and agyria), but fewer subcortical abnormalities were noted. CONCLUSIONS Comparison of MRIs from patients with known mutations of tubulin genes and microtubule-associated proteins allows the establishment of some early correlations of phenotype with genotype and may assist in identification and diagnosis of these rare disorders.
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Affiliation(s)
- C A Mutch
- From the Department of Radiology and Biomedical Imaging (C.A.M., A.J.B.), University of California, San Francisco, San Francisco, California
| | - A Poduri
- Epilepsy Genetics Program (A.P., B.B., C.A.W.), Division of Epilepsy and Clinical Neurophysiology F.M. Kirby Neurobiology Center (A.P., B.B., C.A.W.) Division of Genetics and Genomics (B.B., C.A.W.), Department of Medicine, Manton Center for Orphan Disease Research and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts Department of Neurology (A.P., M.S., B.B., C.A.W.), Harvard Medical School, Boston, Massachusetts
| | - M Sahin
- Department of Neurology (A.P., M.S., B.B., C.A.W.), Harvard Medical School, Boston, Massachusetts
| | - B Barry
- Epilepsy Genetics Program (A.P., B.B., C.A.W.), Division of Epilepsy and Clinical Neurophysiology F.M. Kirby Neurobiology Center (A.P., B.B., C.A.W.) Department of Neurology (A.P., M.S., B.B., C.A.W.), Harvard Medical School, Boston, Massachusetts
| | - C A Walsh
- Epilepsy Genetics Program (A.P., B.B., C.A.W.), Division of Epilepsy and Clinical Neurophysiology F.M. Kirby Neurobiology Center (A.P., B.B., C.A.W.) Division of Genetics and Genomics (B.B., C.A.W.), Department of Medicine, Manton Center for Orphan Disease Research and Howard Hughes Medical Institute, Boston Children's Hospital, Boston, Massachusetts Department of Neurology (A.P., M.S., B.B., C.A.W.), Harvard Medical School, Boston, Massachusetts
| | - A J Barkovich
- From the Department of Radiology and Biomedical Imaging (C.A.M., A.J.B.), University of California, San Francisco, San Francisco, California
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63
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Stamou MI, Cox KH, Crowley WF. Withdrawn: Discovering Genes Essential to the Hypothalamic Regulation of Human Reproduction Using a Human Disease Model: Adjusting to Life in the "-Omics" Era. Endocr Rev 2016; 2016:4-22. [PMID: 27454361 PMCID: PMC6958992 DOI: 10.1210/er.2015-1045.2016.1.test] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 09/15/2015] [Indexed: 12/17/2022]
Abstract
The neuroendocrine regulation of reproduction is an intricate process requiring the exquisite coordination of an assortment of cellular networks, all converging on the GnRH neurons. These neurons have a complex life history, migrating mainly from the olfactory placode into the hypothalamus, where GnRH is secreted and acts as the master regulator of the hypothalamic-pituitary-gonadal axis. Much of what we know about the biology of the GnRH neurons has been aided by discoveries made using the human disease model of isolated GnRH deficiency (IGD), a family of rare Mendelian disorders that share a common failure of secretion and/or action of GnRH causing hypogonadotropic hypogonadism. Over the last 30 years, research groups around the world have been investigating the genetic basis of IGD using different strategies based on complex cases that harbor structural abnormalities or single pleiotropic genes, endogamous pedigrees, candidate gene approaches as well as pathway gene analyses. Although such traditional approaches, based on well-validated tools, have been critical to establish the field, new strategies, such as next-generation sequencing, are now providing speed and robustness, but also revealing a surprising number of variants in known IGD genes in both patients and healthy controls. Thus, before the field moves forward with new genetic tools and continues discovery efforts, we must reassess what we know about IGD genetics and prepare to hold our work to a different standard. The purpose of this review is to: 1) look back at the strategies used to discover the "known" genes implicated in the rare forms of IGD; 2) examine the strengths and weaknesses of the methodologies used to validate genetic variation; 3)substantiate the role of known genes in the pathophysiology of the disease; and 4) project forward as we embark upon a widening use of these new and powerful technologies for gene discovery. (Endocrine Reviews 36: 603-621, 2015).
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Affiliation(s)
- M I Stamou
- Harvard National Center for Translational Research in Reproduction and Infertility, Reproductive Endocrine Unit of the Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114
| | - K H Cox
- Harvard National Center for Translational Research in Reproduction and Infertility, Reproductive Endocrine Unit of the Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114
| | - William F Crowley
- Harvard National Center for Translational Research in Reproduction and Infertility, Reproductive Endocrine Unit of the Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114
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64
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Shimojima K, Okamoto N, Yamamoto T. A novel
TUBB3
mutation in a sporadic patient with asymmetric cortical dysplasia. Am J Med Genet A 2016; 170A:1076-9. [DOI: 10.1002/ajmg.a.37545] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 12/21/2015] [Indexed: 11/06/2022]
Affiliation(s)
- Keiko Shimojima
- Precursory Research for Embryonic Science and Technology (PRESTO)Japan Science and Technology Agency (JST)KawaguchiJapan
- Tokyo Women's Medical University Institute for Integrated Medical SciencesTokyoJapan
| | - Nobuhiko Okamoto
- Department of Medical GeneticsOsaka Medical Center and Research Institute for Maternal and Child HealthOsakaJapan
| | - Toshiyuki Yamamoto
- Tokyo Women's Medical University Institute for Integrated Medical SciencesTokyoJapan
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65
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Whitman MC, Andrews C, Chan WM, Tischfield MA, Stasheff SF, Brancati F, Ortiz-Gonzalez X, Nuovo S, Garaci F, MacKinnon SE, Hunter DG, Grant PE, Engle EC. Two unique TUBB3 mutations cause both CFEOM3 and malformations of cortical development. Am J Med Genet A 2015; 170A:297-305. [PMID: 26639658 DOI: 10.1002/ajmg.a.37362] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 08/27/2015] [Indexed: 11/09/2022]
Abstract
One set of missense mutations in the neuron specific beta tubulin isotype 3 (TUBB3) has been reported to cause malformations of cortical development (MCD), while a second set has been reported to cause isolated or syndromic Congenital Fibrosis of the Extraocular Muscles type 3 (CFEOM3). Because TUBB3 mutations reported to cause CFEOM had not been associated with cortical malformations, while mutations reported to cause MCD had not been associated with CFEOM or other forms of paralytic strabismus, it was hypothesized that each set of mutations might alter microtubule function differently. Here, however, we report two novel de novo heterozygous TUBB3 amino acid substitutions, G71R and G98S, in four patients with both MCD and syndromic CFEOM3. These patients present with moderately severe CFEOM3, nystagmus, torticollis, and developmental delay, and have intellectual and social disabilities. Neuroimaging reveals defective cortical gyration, as well as hypoplasia or agenesis of the corpus callosum and anterior commissure, malformations of hippocampi, thalami, basal ganglia and cerebella, and brainstem and cranial nerve hypoplasia. These new TUBB3 substitutions meld the two previously distinct TUBB3-associated phenotypes, and implicate similar microtubule dysfunction underlying both.
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Affiliation(s)
- Mary C Whitman
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts.,Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts.,FM Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts
| | - Caroline Andrews
- FM Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts.,Department of Neurology, Boston Children's Hospital, Boston, Massachusetts.,Department of Neurology, Harvard Medical School, Boston, Massachusetts.,Howard Hughes Medical Institute, Chevy Chase, Maryland
| | - Wai-Man Chan
- FM Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts.,Department of Neurology, Boston Children's Hospital, Boston, Massachusetts.,Department of Neurology, Harvard Medical School, Boston, Massachusetts.,Howard Hughes Medical Institute, Chevy Chase, Maryland.,Program in Genomics, Boston Children's Hospital, Boston, Massachusetts
| | - Max A Tischfield
- FM Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts.,Department of Neurology, Boston Children's Hospital, Boston, Massachusetts.,Department of Neurology, Harvard Medical School, Boston, Massachusetts
| | - Steven F Stasheff
- Departments of Pediatrics (Neurology), Ophthalmology and Visual Sciences, Neurology and Biomedical Engineering, University of Iowa, Iowa City, Iowa
| | - Francesco Brancati
- Department of Medical, Oral and Biotechnological Sciences, Gabriele d'Annunzio University, Chieti, Italy
| | - Xilma Ortiz-Gonzalez
- Department of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Sara Nuovo
- Department of Biomedicine and Prevention, Tor Vergata University, Rome, Italy
| | - Francesco Garaci
- Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, Tor Vergata University, Rome, Italy
| | - Sarah E MacKinnon
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts
| | - David G Hunter
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts.,Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
| | - P Ellen Grant
- Department of Radiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Elizabeth C Engle
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts.,Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts.,FM Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts.,Department of Neurology, Boston Children's Hospital, Boston, Massachusetts.,Department of Neurology, Harvard Medical School, Boston, Massachusetts.,Howard Hughes Medical Institute, Chevy Chase, Maryland.,Program in Genomics, Boston Children's Hospital, Boston, Massachusetts.,Broad Institute of MIT and Harvard, Cambridge, Massachusetts.,The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts.,Department of Medicine (Genetics), Boston Children's Hospital, Boston, Massachusetts
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66
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Stamou MI, Cox KH, Crowley WF. Discovering Genes Essential to the Hypothalamic Regulation of Human Reproduction Using a Human Disease Model: Adjusting to Life in the "-Omics" Era. Endocr Rev 2015; 36:603-21. [PMID: 26394276 PMCID: PMC4702497 DOI: 10.1210/er.2015-1045] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 09/15/2015] [Indexed: 12/23/2022]
Abstract
The neuroendocrine regulation of reproduction is an intricate process requiring the exquisite coordination of an assortment of cellular networks, all converging on the GnRH neurons. These neurons have a complex life history, migrating mainly from the olfactory placode into the hypothalamus, where GnRH is secreted and acts as the master regulator of the hypothalamic-pituitary-gonadal axis. Much of what we know about the biology of the GnRH neurons has been aided by discoveries made using the human disease model of isolated GnRH deficiency (IGD), a family of rare Mendelian disorders that share a common failure of secretion and/or action of GnRH causing hypogonadotropic hypogonadism. Over the last 30 years, research groups around the world have been investigating the genetic basis of IGD using different strategies based on complex cases that harbor structural abnormalities or single pleiotropic genes, endogamous pedigrees, candidate gene approaches as well as pathway gene analyses. Although such traditional approaches, based on well-validated tools, have been critical to establish the field, new strategies, such as next-generation sequencing, are now providing speed and robustness, but also revealing a surprising number of variants in known IGD genes in both patients and healthy controls. Thus, before the field moves forward with new genetic tools and continues discovery efforts, we must reassess what we know about IGD genetics and prepare to hold our work to a different standard. The purpose of this review is to: 1) look back at the strategies used to discover the "known" genes implicated in the rare forms of IGD; 2) examine the strengths and weaknesses of the methodologies used to validate genetic variation; 3) substantiate the role of known genes in the pathophysiology of the disease; and 4) project forward as we embark upon a widening use of these new and powerful technologies for gene discovery.
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Affiliation(s)
- M I Stamou
- Harvard National Center for Translational Research in Reproduction and Infertility, Reproductive Endocrine Unit of the Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114
| | - K H Cox
- Harvard National Center for Translational Research in Reproduction and Infertility, Reproductive Endocrine Unit of the Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114
| | - William F Crowley
- Harvard National Center for Translational Research in Reproduction and Infertility, Reproductive Endocrine Unit of the Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114
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67
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TUBA1A Mutation Associated With Eye Abnormalities in Addition to Brain Malformation. Pediatr Neurol 2015; 53:442-4. [PMID: 26294046 DOI: 10.1016/j.pediatrneurol.2015.07.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 07/09/2015] [Accepted: 07/11/2015] [Indexed: 01/10/2023]
Abstract
OBJECTIVE We describe the case of a boy with a TUBA1A mutation presenting with microphthalmia and congenital cataracts in addition to microcephaly and severe brain malformation. METHODS A boy presented in early infancy with microphthalmia, congenital cataracts, and microcephaly. His neurological course included severe hypotonia and drug-resistant epilepsy. Magnetic resonance imaging of the brain revealed a complex malformation that included agenesis of the corpus callosum, severely hypoplastic cerebellar vermis, mildly hypoplastic and dysplastic cerebellar hemispheres, mildly hypoplastic brainstem, mild posterior simplified cerebral gyral pattern, dysplastic basal ganglia and thalami, hypoplastic optic nerves, and absent olfactory bulbs. RESULTS TUBA1A genetic testing was conducted and revealed a previously unreported heterozygous 808G>T missense mutation. Parental genetic testing was negative, indicating that the child's mutation was de novo. CONCLUSION The TUBA1A gene encodes tubulin alpha-1A, a protein with an important role in microtubule function and stability. Human mutations can result in a wide spectrum of brain malformations including lissencephaly, microlissencephaly, cerebellar hypoplasia, agenesis of the corpus callosum, pachygyria and polymicrogyria. Although TUBA1A is expressed in both developing brain and retinal tissue, there are no reported cases of TUBA1A mutations in association with major developmental ophthalmologic abnormalities.
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68
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Gutowski NJ, Chilton JK. The congenital cranial dysinnervation disorders. Arch Dis Child 2015; 100:678-81. [PMID: 25633065 DOI: 10.1136/archdischild-2014-307035] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Accepted: 01/07/2015] [Indexed: 11/04/2022]
Abstract
Congenital cranial dysinnervation disorders (CCDD) encompass a number of related conditions and includes Duane syndrome, congenital fibrosis of the external ocular muscles, Möbius syndrome, congenital ptosis and hereditary congenital facial paresis. These are congenital disorders where the primary findings are non-progressive and are caused by developmental abnormalities of cranial nerves/nuclei with primary or secondary dysinnervation. Several CCDD genes have been found, which enhance our understanding of the mechanisms involved in brain stem development and axonal guidance.
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Affiliation(s)
- N J Gutowski
- Department of Neurology, Royal Devon and Exeter Foundation Hospital, Exeter, UK University of Exeter Medical School, Exeter, UK
| | - J K Chilton
- University of Exeter Medical School, Exeter, UK
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69
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Oegema R, Cushion TD, Phelps IG, Chung SK, Dempsey JC, Collins S, Mullins JGL, Dudding T, Gill H, Green AJ, Dobyns WB, Ishak GE, Rees MI, Doherty D. Recognizable cerebellar dysplasia associated with mutations in multiple tubulin genes. Hum Mol Genet 2015; 24:5313-25. [PMID: 26130693 DOI: 10.1093/hmg/ddv250] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 06/24/2015] [Indexed: 01/06/2023] Open
Abstract
Mutations in alpha- and beta-tubulins are increasingly recognized as a major cause of malformations of cortical development (MCD), typically lissencephaly, pachygyria and polymicrogyria; however, sequencing tubulin genes in large cohorts of MCD patients has detected tubulin mutations in only 1-13%. We identified patients with a highly characteristic cerebellar dysplasia but without lissencephaly, pachygyria and polymicrogyria typically associated with tubulin mutations. Remarkably, in seven of nine patients (78%), targeted sequencing revealed mutations in three different tubulin genes (TUBA1A, TUBB2B and TUBB3), occurring de novo or inherited from a mosaic parent. Careful re-review of the cortical phenotype on brain imaging revealed only an irregular pattern of gyri and sulci, for which we propose the term tubulinopathy-related dysgyria. Basal ganglia (100%) and brainstem dysplasia (80%) were common features. On the basis of in silico structural predictions, the mutations affect amino acids in diverse regions of the alpha-/beta-tubulin heterodimer, including the nucleotide binding pocket. Cell-based assays of tubulin dynamics reveal various effects of the mutations on incorporation into microtubules: TUBB3 p.Glu288Lys and p.Pro357Leu do not incorporate into microtubules at all, whereas TUBB2B p.Gly13Ala shows reduced incorporation and TUBA1A p.Arg214His incorporates fully, but at a slower rate than wild-type. The broad range of effects on microtubule incorporation is at odds with the highly stereotypical clinical phenotype, supporting differential roles for the three tubulin genes involved. Identifying this highly characteristic phenotype is important due to the low recurrence risk compared with the other (recessive) cerebellar dysplasias and the apparent lack of non-neurological medical issues.
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Affiliation(s)
- Renske Oegema
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands,
| | | | | | - Seo-Kyung Chung
- Institute of Life Science, College of Medicine and Wales Epilepsy Research Network (WERN), College of Medicine, Swansea University, Swansea SA2 8PP, UK
| | | | - Sarah Collins
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | | | - Tracy Dudding
- Hunter Genetics, Waratah, New South Wales, Australia, University of Newcastle, Callaghan, New South Wales, Australia
| | - Harinder Gill
- National Centre for Medical Genetics, Our Lady's Children's Hospital, Dublin 12, Ireland and
| | - Andrew J Green
- National Centre for Medical Genetics, Our Lady's Children's Hospital, Dublin 12, Ireland and School of Medicine and Medical Science, University College Dublin, Dublin 4, Ireland
| | - William B Dobyns
- Department of Pediatrics, Department of Neurology and Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Gisele E Ishak
- Department of Radiology, Seattle Children's Hospital and University of Washington, Seattle, WA 98195, USA
| | - Mark I Rees
- Institute of Life Science, College of Medicine and Wales Epilepsy Research Network (WERN), College of Medicine, Swansea University, Swansea SA2 8PP, UK
| | - Dan Doherty
- Department of Pediatrics, Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA,
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70
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Grønborg S, Kjaergaard S, Hove H, Larsen VA, Kirchhoff M. Monozygotic twins with a de novo 0.32 Mb 16q24.3 deletion, including TUBB3 presenting with developmental delay and mild facial dysmorphism but without overt brain malformation. Am J Med Genet A 2015; 167A:2731-6. [PMID: 26109418 DOI: 10.1002/ajmg.a.37227] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Accepted: 06/10/2015] [Indexed: 01/09/2023]
Abstract
Nervous system development is highly dependent on the function of microtubules, which are assembled from tubulin heterodimers containing several α- and β-tubulin isotypes encoded by separate genes. A spectrum of neurological disorders with malformations of the central nervous system has recently been associated with missense mutations in this group of genes. Here, we report two patients, monozygotic twins, carrying a de novo 0.32 Mb deletion of chromosome 16q24.3 including the TUBB3 gene. The patients presented with global developmental delay, mild facial dysmorphism, secondary microcephaly, and mild spastic diplegia. Cerebral magnetic resonance imaging of the patients did not reveal cortical malformations, malformations of the corticospinal tracts, basal ganglia, corpus callosum, or optic nerves. This observation is in contrast to the group of neurological disorders that are associated with heterozygous missense mutations in genes encoding different neuronal α- and β-tubulin isotypes, termed tubulinopathies. On the background of current knowledge regarding the function and genotype-phenotype correlations of mutations in the neuronal tubulin isotypes, the clinical and diagnostic findings in these patients are discussed. To our knowledge, this is the first report of patients with a de novo deletion of the TUBB3 gene. The lack of cortical or other cerebral malformations supports the current hypothesis that TUBB3-related tubulinopathies are caused by altered protein function.
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Affiliation(s)
- Sabine Grønborg
- Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Susanne Kjaergaard
- Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Hanne Hove
- Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Vibeke André Larsen
- Department of Neuroradiology, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Maria Kirchhoff
- Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
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71
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Barkovich AJ, Dobyns WB, Guerrini R. Malformations of cortical development and epilepsy. Cold Spring Harb Perspect Med 2015; 5:a022392. [PMID: 25934463 DOI: 10.1101/cshperspect.a022392] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Malformations of cortical development (MCDs) are an important cause of epilepsy and an extremely interesting group of disorders from the perspective of brain development and its perturbations. Many new MCDs have been described in recent years as a result of improvements in imaging, genetic testing, and understanding of the effects of mutations on the ability of their protein products to correctly function within the molecular pathways by which the brain functions. In this review, most of the major MCDs are reviewed from a clinical, embryological, and genetic perspective. The most recent literature regarding clinical diagnosis, mechanisms of development, and future paths of research are discussed.
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Affiliation(s)
- A James Barkovich
- Department of Radiology and Biomedical Imaging, Neurology, Pediatrics, and Neurosurgery, University of California, San Francisco, San Francisco, California 94143-0628
| | - William B Dobyns
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington 98101
| | - Renzo Guerrini
- Pediatric Neurology Unit and Laboratories, Children's Hospital A. Meyer, University of Florence, Florence 50139, Italy
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Balasubramanian R, Chew S, MacKinnon SE, Kang PB, Andrews C, Chan WM, Engle EC. Expanding the phenotypic spectrum and variability of endocrine abnormalities associated with TUBB3 E410K syndrome. J Clin Endocrinol Metab 2015; 100:E473-7. [PMID: 25559402 PMCID: PMC4333039 DOI: 10.1210/jc.2014-4107] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
CONTEXT A heterozygous de novo c.1228G>A mutation (E410K) in the TUBB3 gene encoding the neuronal-specific β-tubulin isotype 3 (TUBB3) causes the TUBB3 E410K syndrome characterized by congenital fibrosis of the extraocular muscles (CFEOM), facial weakness, intellectual and social disabilities, and Kallmann syndrome (anosmia with hypogonadotropic hypogonadism). All TUBB3 E410K subjects reported to date are sporadic cases. OBJECTIVE This study aimed to report the clinical, genetic, and molecular features of a familial presentation of the TUBB3 E410K syndrome. DESIGN Case report of a mother and three affected children with clinical features of the TUBB3 E410K syndrome. SETTING Academic Medical Center. MAIN OUTCOME MEASURES Genetic analysis of the TUBB3 gene and clinical evaluation of endocrine and nonendocrine phenotypes. RESULTS A de novo TUBB3 c.1228G>A mutation arose in a female proband who displayed CFEOM, facial weakness, intellectual and social disabilities, and anosmia. However, she underwent normal sexual development at puberty and had three spontaneous pregnancies with subsequent autosomal-dominant inheritance of the mutation by her three boys. All sons displayed nonendocrine features of the TUBB3 E410K syndrome similar to their mother but, in addition, had variable features suggestive of additional endocrine abnormalities. CONCLUSIONS This first report of an autosomal-dominant inheritance of the TUBB3 c.1228G>A mutation in a family provides new insights into the spectrum and variability of endocrine phenotypes associated with the TUBB3 E410K syndrome. These observations emphasize the need for appropriate clinical evaluation and complicate genetic counseling of patients and families with this syndrome.
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Affiliation(s)
- Ravikumar Balasubramanian
- Harvard Reproductive Endocrine Sciences Center (R.B.), The Reproductive Endocrine Unit of the Department of Medicine (R.B.), Massachusetts General Hospital, Boston, Massachusetts 02114; Harvard Medical School (R.B., S.C., P.B.K., C.A., W.-M.C., E.C.E.), Boston, Massachusetts 02115; Department of Neurology (S.C., P.B.K., C.A., W.-M.C., E.C.E.), Kirby Neurobiology Center (S.C., C.A., W.-M.C., E.C.E.), and Department of Ophthalmology (S.E.M., E.C.E.), Boston Children's Hospital, Boston, Massachusetts 02115; and Howard Hughes Medical Institute (S.C., C.A., W.-M.C., E.C.E.), Chevy Chase, Maryland 20815
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Romaniello R, Arrigoni F, Bassi MT, Borgatti R. Mutations in α- and β-tubulin encoding genes: implications in brain malformations. Brain Dev 2015; 37:273-80. [PMID: 25008804 DOI: 10.1016/j.braindev.2014.06.002] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 05/26/2014] [Accepted: 06/02/2014] [Indexed: 12/24/2022]
Abstract
The tubulin gene family is mainly expressed in post-mitotic neurons during cortical development with a specific spatial and temporal expression pattern. Members of this family encode dimeric proteins consisting of two closely related subunits (α and β), representing the major constituents of microtubules. Tubulin genes play a crucial role in the mechanisms of the Central Nervous System development such as neuronal migration and axonal guidance (axon outgrowth and maintenance). Different mutations in α/β-tubulin genes (TUBA1A, TUBA8, TUBB2A, TUBB4A, TUBB2B, TUBB3, and TUBB) might alter the dynamic properties and functions of microtubules in several ways, effecting a reduction in the number of functional tubulin heterodimers and causing alterations in GTP binding and disruptions of the binding of other proteins to microtubules (motor proteins and other microtubule interacting proteins). In recent years an increasing number of brain malformations has been associated with mutations in tubulin genes: malformations of cortical development such as lissencephaly and various grades of gyral disorganization, focal or diffuse polymicrogyria and open or closed-lips schizencephaly as likely consequences of an altered neuronal migration process; abnormalities or agenesis of the midline commissural structures (anterior commissure, corpus callosum and fornix), hypoplasia of the oculomotor and optic nerves, dysmorphisms of the hind-brain as expression of axon guidance disorders. Dysmorphisms of the basal ganglia (fusion between the caudate nucleus and putamen with absence of the anterior limb of the internal capsule) and hippocampi were also observed. A rare form of leukoencephalopathy characterized by hypomyelination with atrophy of the basal ganglia an cerebellum (H-ABC) was also recently described. The present review, describing the structural and functional features of tubulin genes, aims to revise the main cerebral associated malformations and related clinical aspects, suggesting a genotype-phenotype correlation.
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Affiliation(s)
- Romina Romaniello
- Neuropsychiatry and Neurorehabilitation Unit, IRCCS Eugenio Medea, Bosisio Parini, Lecco, Italy
| | - Filippo Arrigoni
- Neuroimaging Unit, IRCCS Eugenio Medea, Bosisio Parini, Lecco, Italy
| | - Maria Teresa Bassi
- Laboratory of Molecular Biology, IRCCS Eugenio Medea, Bosisio Parini, Lecco, Italy
| | - Renato Borgatti
- Neuropsychiatry and Neurorehabilitation Unit, IRCCS Eugenio Medea, Bosisio Parini, Lecco, Italy.
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Hsu AK, Rosow DE, Wallerstein RJ, April MM. Familial congenital bilateral vocal fold paralysis: a novel gene translocation. Int J Pediatr Otorhinolaryngol 2015; 79:323-7. [PMID: 25617187 DOI: 10.1016/j.ijporl.2014.12.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 12/08/2014] [Accepted: 12/09/2014] [Indexed: 11/28/2022]
Abstract
OBJECTIVES True vocal fold (TVF) paralysis is a common cause of neonatal stridor and airway obstruction, though bilateral TVF paralysis is seen less frequently. Rare cases of familial congenital TVF paralysis have been described with implied genetic origin, but few genetic abnormalities have been discovered to date. The purpose of this study is to describe a novel chromosomal translocation responsible for congenital bilateral TVF immobility. METHODS The charts of three patients were retrospectively reviewed: a 35 year-old woman and her two children. The mother had bilateral TVF paralysis at birth requiring tracheotomy. Her oldest child had a similar presentation at birth and also required tracheotomy, while the younger child had laryngomalacia without TVF paralysis. Standard karyotype analysis was done using samples from all three patients and the parents of the mother, to assess whether a chromosomal abnormality was responsible. RESULTS Karyotype analysis revealed the same balanced translocation between chromosomes 5 and 14, t(5;14) (p15.3, q11.2) in the mother and her two daughters. No other genetic abnormalities were identified. Neither maternal grandparent had the translocation, which appeared to be a spontaneous mutation in the mother with autosomal dominant inheritance and variable penetrance. CONCLUSIONS A novel chromosomal translocation was identified that appears to be responsible for familial congenital bilateral TVF paralysis. While there are other reports of genetic abnormalities responsible for this condition, we believe this is the first describing this particular translocation.
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Affiliation(s)
- Amy K Hsu
- Department of Otolaryngology/Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA, United States
| | - David E Rosow
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL, United States.
| | - Robert J Wallerstein
- Department of Pediatrics, Santa Clara Valley Medical Center, San Jose, CA, United States
| | - Max M April
- Department of Otolaryngology/Head and Neck Surgery, New York University School of Medicine, New York, NY, United States
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Kadakia S, Helman SN, Schwedhelm T, Saman M, Azizzadeh B. Examining the genetics of congenital facial paralysis--a closer look at Moebius syndrome. Oral Maxillofac Surg 2015; 19:109-16. [PMID: 25663568 DOI: 10.1007/s10006-015-0485-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Accepted: 01/26/2015] [Indexed: 01/15/2023]
Abstract
OBJECTIVES The molecular underpinnings of Moebius syndrome (MBS) are diverse. This article provides a comprehensive summation of the genetic and etiologic literature underlying this disorder. Elucidating the genetic causes of the disorder can aid in earlier detection and treatment planning. DESIGN Articles from 1880-2013 were selected and reviewed by six researchers to understand all of the molecular theories and chronicity of advancements in the literature. RESULTS Mutations in the MBS1, MBS2, and MBS3 gene loci all have contributed to the development of MBS through various pathways. HOX family genes coding for homeobox domains, also, have been implicated in the abnormal development of the human brain. These are among the numerous genes that have been linked to the development of MBS. CONCLUSION Our study codified nascent findings of the molecular determinants of MBS. These findings add to a growing database of MBS-associated mutations and can be used to diagnose MBS and clarify pathogenesis.
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Affiliation(s)
- Sameep Kadakia
- Department of Otolaryngology-Head and Neck Surgery, New York Eye and Ear Infirmary-Mount Sinai Health System, 310 East 14th Street, 6th Floor, New York, NY, 10009, USA,
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Oystreck D. Congenital and Genetic Ocular Motility Disorders: Update and Considerations. THE AMERICAN ORTHOPTIC JOURNAL 2015; 65:58-66. [PMID: 26564928 DOI: 10.3368/aoj.65.1.58] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Concepts regarding certain forms of congenital eye movement disorders have recently changed, due in large part to new genetic evidence identifying causative genes and their role in the development of extraocular muscle innervation. This group is now referred to as the Congenital Cranial Dysinnervation Disorders (CCDDs). Careful assessment of phenotypic features that include both ophthalmological and non-ophthalmological features in genetically defined individuals has led to the development of a more robust classification system. Correlating phenotypes with new genetically defined syndromes has improved the ability of the clinician/researcher to better determine a definitive diagnosis in patients with complex ocular motility disorders. Nevertheless, more work is still required.
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Affiliation(s)
- Darren Oystreck
- From the IWK Health Centre Eye Care Team, Halifax, Nova Scotia, Canada; From the Faculty of Health Professions, Dalhousie University, Halifax, Nova Scotia, Canada; From the Division of Ophthalmology, Faculty of Health Sciences, University of Stellenbosch, Tygerberg, South Africa.
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Erro R, Hersheson J, Ganos C, Mencacci NE, Stamelou M, Batla A, Thust SC, Bras JM, Guerreiro RJ, Hardy J, Quinn NP, Houlden H, Bhatia KP. H-ABC syndrome and DYT4: Variable expressivity or pleiotropy of TUBB4 mutations? Mov Disord 2014; 30:828-33. [DOI: 10.1002/mds.26129] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 10/27/2014] [Accepted: 10/29/2014] [Indexed: 12/21/2022] Open
Affiliation(s)
- Roberto Erro
- Sobell Department of Motor Neuroscience and Movement Disorders; University College London (UCL) Institute of Neurology; London United Kingdom
- Dipartimento di Scienze Neurologiche e del Movimento; Università di Verona; Verona Italy
| | - Joshua Hersheson
- Department of Molecular Neuroscience; UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery; London United Kingdom
| | - Christos Ganos
- Sobell Department of Motor Neuroscience and Movement Disorders; University College London (UCL) Institute of Neurology; London United Kingdom
- University Medical Center Hamburg-Eppendorf (UKE); Neurology Hamburg Germany
| | - Niccoló E. Mencacci
- Department of Molecular Neuroscience; UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery; London United Kingdom
| | - Maria Stamelou
- Sobell Department of Motor Neuroscience and Movement Disorders; University College London (UCL) Institute of Neurology; London United Kingdom
- Second Department of Neurology; Kapodistrian University of Athens; Greece
- Neurology Clinic; Philipps University; Marburg Germany
| | - Amit Batla
- Sobell Department of Motor Neuroscience and Movement Disorders; University College London (UCL) Institute of Neurology; London United Kingdom
| | - Stefanie Catherine Thust
- The Lysholm Department of Neuroradiology; National Hospital for Neurology and Neurosurgery; London United Kingdom
| | - Jose M. Bras
- Department of Molecular Neuroscience; UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery; London United Kingdom
| | - Rita J. Guerreiro
- Department of Molecular Neuroscience; UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery; London United Kingdom
| | - John Hardy
- Department of Molecular Neuroscience; UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery; London United Kingdom
| | - Niall P. Quinn
- Sobell Department of Motor Neuroscience and Movement Disorders; University College London (UCL) Institute of Neurology; London United Kingdom
| | - Henry Houlden
- Department of Molecular Neuroscience; UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery; London United Kingdom
| | - Kailash P. Bhatia
- Sobell Department of Motor Neuroscience and Movement Disorders; University College London (UCL) Institute of Neurology; London United Kingdom
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Abstract
Axonal transport is essential for neuronal function, and many neurodevelopmental and neurodegenerative diseases result from mutations in the axonal transport machinery. Anterograde transport supplies distal axons with newly synthesized proteins and lipids, including synaptic components required to maintain presynaptic activity. Retrograde transport is required to maintain homeostasis by removing aging proteins and organelles from the distal axon for degradation and recycling of components. Retrograde axonal transport also plays a major role in neurotrophic and injury response signaling. This review provides an overview of axonal transport pathways and discusses their role in neuronal function.
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79
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Bahi-Buisson N, Poirier K, Fourniol F, Saillour Y, Valence S, Lebrun N, Hully M, Bianco CF, Boddaert N, Elie C, Lascelles K, Souville I, Beldjord C, Chelly J. The wide spectrum of tubulinopathies: what are the key features for the diagnosis? ACTA ACUST UNITED AC 2014; 137:1676-700. [PMID: 24860126 DOI: 10.1093/brain/awu082] [Citation(s) in RCA: 206] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Complex cortical malformations associated with mutations in tubulin genes: TUBA1A, TUBA8, TUBB2B, TUBB3, TUBB5 and TUBG1 commonly referred to as tubulinopathies, are a heterogeneous group of conditions with a wide spectrum of clinical severity. Among the 106 patients selected as having complex cortical malformations, 45 were found to carry mutations in TUBA1A (42.5%), 18 in TUBB2B (16.9%), 11 in TUBB3 (10.4%), three in TUBB5 (2.8%), and three in TUBG1 (2.8%). No mutations were identified in TUBA8. Systematic review of patients' neuroimaging and neuropathological data allowed us to distinguish at least five cortical malformation syndromes: (i) microlissencephaly (n = 12); (ii) lissencephaly (n = 19); (iii) central pachygyria and polymicrogyria-like cortical dysplasia (n = 24); (iv) generalized polymicrogyria-like cortical dysplasia (n = 6); and (v) a 'simplified' gyral pattern with area of focal polymicrogyria (n = 19). Dysmorphic basal ganglia are the hallmark of tubulinopathies (found in 75% of cases) and are present in 100% of central pachygyria and polymicrogyria-like cortical dysplasia and simplified gyral malformation syndromes. Tubulinopathies are also characterized by a high prevalence of corpus callosum agenesis (32/80; 40%), and mild to severe cerebellar hypoplasia and dysplasia (63/80; 78.7%). Foetal cases (n = 25) represent the severe end of the spectrum and show specific abnormalities that provide insights into the underlying pathophysiology. The overall complexity of tubulinopathies reflects the pleiotropic effects of tubulins and their specific spatio-temporal profiles of expression. In line with previous reports, this large cohort further clarifies overlapping phenotypes between tubulinopathies and although current structural data do not allow prediction of mutation-related phenotypes, within each mutated gene there is an associated predominant pattern of cortical dysgenesis allowing some phenotype-genotype correlation. The core phenotype of TUBA1A and TUBG1 tubulinopathies are lissencephalies and microlissencephalies, whereas TUBB2B tubulinopathies show in the majority, centrally predominant polymicrogyria-like cortical dysplasia. By contrast, TUBB3 and TUBB5 mutations cause milder malformations with focal or multifocal polymicrogyria-like cortical dysplasia with abnormal and simplified gyral pattern.
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Affiliation(s)
- Nadia Bahi-Buisson
- 1 Institut Cochin, Université Paris-Descartes, CNRS (UMR 8104), Paris, France2 Inserm, U1016, Paris, France3 Université Paris Descartes, Sorbonne Paris Cité, Institut Imagine, Paris, France4 INSERM UMR-1163, Embryology and genetics of congenital malformations, Paris, France5 Service de Neurologie pédiatrique, Assistance Publique-Hôpitaux de Paris (AP-HP), hôpital Necker, Paris, France
| | - Karine Poirier
- 1 Institut Cochin, Université Paris-Descartes, CNRS (UMR 8104), Paris, France2 Inserm, U1016, Paris, France
| | | | - Yoann Saillour
- 1 Institut Cochin, Université Paris-Descartes, CNRS (UMR 8104), Paris, France2 Inserm, U1016, Paris, France
| | - Stéphanie Valence
- 1 Institut Cochin, Université Paris-Descartes, CNRS (UMR 8104), Paris, France2 Inserm, U1016, Paris, France
| | - Nicolas Lebrun
- 1 Institut Cochin, Université Paris-Descartes, CNRS (UMR 8104), Paris, France2 Inserm, U1016, Paris, France
| | - Marie Hully
- 5 Service de Neurologie pédiatrique, Assistance Publique-Hôpitaux de Paris (AP-HP), hôpital Necker, Paris, France
| | | | - Nathalie Boddaert
- 8 Service de Radiologie Pédiatrique, AP-HP, hôpital Necker, Paris, France9 Inserm, U797-INSERM-CEA, Service Hospitalier Frédéric Joliot, CEA, 4, place du General Leclerc, 91406, Orsay, France
| | - Caroline Elie
- 10 BioInformatic Department-AP-HP, hôpital Necker-Enfants Malades, Paris, France
| | | | - Isabelle Souville
- 12 Service de Biologie Moleculaire et Genetique, Pavillon Cassini AP-HP, Hôpital Cochin, Paris, France
| | | | - Cherif Beldjord
- 12 Service de Biologie Moleculaire et Genetique, Pavillon Cassini AP-HP, Hôpital Cochin, Paris, France
| | - Jamel Chelly
- 1 Institut Cochin, Université Paris-Descartes, CNRS (UMR 8104), Paris, France2 Inserm, U1016, Paris, France
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80
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Karakis I, Liew W, Darras BT, Jones HR, Kang PB. Referral and diagnostic trends in pediatric electromyography in the molecular era. Muscle Nerve 2014; 50:244-9. [DOI: 10.1002/mus.24152] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2013] [Revised: 12/11/2013] [Accepted: 12/18/2013] [Indexed: 11/11/2022]
Affiliation(s)
- Ioannis Karakis
- Department of Neurology; Boston Children's Hospital, Harvard Medical School; 300 Longwood Avenue Boston Massachusetts 02115 USA
- Department of Neurology; Lahey Clinic Burlington Massachusetts USA
- Department of Neurology; Emory University School of Medicine; Atlanta Georgia USA
| | - Wendy Liew
- Department of Neurology; Boston Children's Hospital, Harvard Medical School; 300 Longwood Avenue Boston Massachusetts 02115 USA
| | - Basil T. Darras
- Department of Neurology; Boston Children's Hospital, Harvard Medical School; 300 Longwood Avenue Boston Massachusetts 02115 USA
| | - H. Royden Jones
- Department of Neurology; Boston Children's Hospital, Harvard Medical School; 300 Longwood Avenue Boston Massachusetts 02115 USA
- Department of Neurology; Lahey Clinic Burlington Massachusetts USA
| | - Peter B. Kang
- Department of Neurology; Boston Children's Hospital, Harvard Medical School; 300 Longwood Avenue Boston Massachusetts 02115 USA
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81
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Graeber CP, Hunter DG, Engle EC. The genetic basis of incomitant strabismus: consolidation of the current knowledge of the genetic foundations of disease. Semin Ophthalmol 2014; 28:427-37. [PMID: 24138051 DOI: 10.3109/08820538.2013.825288] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In recent years, our understanding of the genetic foundations of incomitant strabismus has grown significantly. Much new understanding has been gleaned since the concept of congenital cranial dysinnervation disorders (CCDDs) was introduced in 2002, and the genetic basis of CCDDs continues to be elucidated. In this review, we aim to provide an update of the genetic and clinical presentation of these disorders. Disorders reviewed include Duane syndrome (DS), HOXA1 and HOXB1 syndromes, Moebius syndrome, congenital fibrosis of the extraocular muscles (CFEOM), and horizontal gaze palsy with progressive scoliosis (HGPPS).
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82
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Ali Z, Xing C, Anwar D, Itani K, Weakley D, Gong X, Pascual JM, Mootha VV. A novel de novo KIF21A mutation in a patient with congenital fibrosis of the extraocular muscles and Möbius syndrome. Mol Vis 2014; 20:368-75. [PMID: 24715754 PMCID: PMC3976685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 03/26/2014] [Indexed: 11/02/2022] Open
Abstract
PURPOSE To describe the phenotypic characteristics and clinical course of a sporadic case of congenital fibrosis of the extraocular muscles (CFEOM) and Möbius syndrome with a de novo mutation in the KIF21A gene encoding a kinesin motor protein. METHODS An individual with the rare combination of CFEOM and Möbius syndrome underwent comprehensive ophthalmologic and neurological evaluations. Magnetic resonance imaging (MRI) including diffusion tensor imaging (DTI) tractigraphy at 3T field strength was used to evaluate orbital, encephalic, and intracranial nerve integrity. The proband and her healthy parents underwent screening for mutations in the KIF21A, PHOX2A, and TUBB3 genes. RESULTS The patient exhibited congenital, nonprogressive, bilateral external ophthalmoplegia, bilateral ptosis, bilateral facial palsy, and developmental delay. Her inability to blink resulted in severe exposure keratopathy and subsequent corneal perforation requiring a penetrating keratoplasty. MRI revealed an unremarkable configuration of the axial central nervous system and preservation of the intracranial portion of cranial nerves I, II, III, V, VI, VII, and VIII (cranial nerve IV is not normally visualized by MRI). A novel and de novo heterozygous KIF21A mutation (c.1056C>G, p.Asp352Glu) in a highly conserved region of the gene was present in the proband. CONCLUSIONS The reported KIF21A D352E mutation and associated phenotype further expand the clinical and mutational spectrum of CFEOM and Möbius syndrome.
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Affiliation(s)
- Zahra Ali
- University of Texas Southwestern Medical Center, Department of Ophthalmology, Dallas, TX
| | - Chao Xing
- University of Texas Southwestern Medical Center, McDermott Center for Human Growth and Development / Center for Human Genetics, Dallas, TX
| | - Didar Anwar
- University of Texas Southwestern Medical Center, Department of Ophthalmology, Dallas, TX
| | - Kamel Itani
- University of Texas Southwestern Medical Center, Department of Ophthalmology, Dallas, TX
| | - David Weakley
- University of Texas Southwestern Medical Center, Department of Ophthalmology, Dallas, TX
| | - Xin Gong
- University of Texas Southwestern Medical Center, Department of Ophthalmology, Dallas, TX
| | - Juan M. Pascual
- University of Texas Southwestern Medical Center, Rare Brain Disorders Program, Departments of Neurology and Neurotherapeutics, Physiology and Pediatrics, Dallas, TX
| | - V. Vinod Mootha
- University of Texas Southwestern Medical Center, Department of Ophthalmology, Dallas, TX,University of Texas Southwestern Medical Center, McDermott Center for Human Growth and Development / Center for Human Genetics, Dallas, TX
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83
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MacKinnon S, Oystreck DT, Andrews C, Chan WM, Hunter DG, Engle EC. Diagnostic distinctions and genetic analysis of patients diagnosed with moebius syndrome. Ophthalmology 2014; 121:1461-8. [PMID: 24612975 DOI: 10.1016/j.ophtha.2014.01.006] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 01/02/2014] [Accepted: 01/03/2014] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE To improve diagnostic assessment in Moebius syndrome by (1) creating more selective diagnostic subgroups and (2) conducting genetic evaluation in a large patient cohort. DESIGN Prospective, observational study. PARTICIPANTS Attendees of 3 consecutive Moebius syndrome conferences held in the United States, with a prior diagnosis of Moebius syndrome, were invited to participate. METHODS Participants underwent standardized ophthalmologic examination for Moebius syndrome minimum diagnostic criteria (MDC) (congenital, nonprogressive facial palsy, and abduction deficit) and genetic testing for HOXA1, HOXB1, and TUBB3 mutations. MAIN OUTCOME MEASURES The number of patients meeting MDC and the number of patients with confirmed genetic mutation. RESULTS A total of 112 participants from 107 families enrolled. Nineteen percent of participants (21/112) did not meet accepted MDC for Moebius syndrome because they had abduction deficits without facial palsy or facial palsy with full ocular motility. All 5 families with 2 affected individuals had at least 1 family member in this category, including 2 siblings with comitant strabismus who harbored a HOXB1 mutation. Four unrelated participants, also not meeting MDC, had large-angle exotropia, vertical gaze deficiency, and ptosis consistent with congenital fibrosis of the extraocular muscles type 3 (CFEOM3); 1 patient harbored a novel TUBB3 mutation, and 3 patients harbored previously reported de novo TUBB3 mutations. Three percent of participants (3/112) met MDC but also had restricted vertical gaze. The remaining 88 participants (79%) met MDC and had full vertical gaze. This group had relatively homogeneous findings, and none had a family history of Moebius syndrome. Two previously undescribed phenomena were observed in this category: (1) volitional Bell's phenomenon and (2) intorsion with fixation. CONCLUSIONS Although the genetic contributors to classic Moebius syndrome remain elusive, accuracy in clinical evaluation will properly subdivide patients to facilitate genetic testing as new candidate genes are identified. Failure to test ocular motility may lead to misdiagnosis of Moebius syndrome, especially in patients who have facial palsy with full ductions. Patients with exotropia, vertical gaze limitation, and ptosis do not have classic Moebius syndrome and may have TUBB3 mutations associated with CFEOM3. To optimize genetic analysis, we propose adding "full vertical motility" to the MDC for Moebius syndrome.
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Affiliation(s)
- Sarah MacKinnon
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts
| | - Darren T Oystreck
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts; Department of Ophthalmology, College of Medicine, King Saud University, Riyadh, Saudi Arabia; Division of Ophthalmology, Faculty of Health Sciences, University of Stellenbosch, Tygerberg, South Africa
| | - Caroline Andrews
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts; Department of Neurology, Harvard Medical School, Boston, Massachusetts; Howard Hughes Medical Institute, Chevy Chase, Maryland
| | - Wai-Man Chan
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts; Department of Neurology, Harvard Medical School, Boston, Massachusetts; Howard Hughes Medical Institute, Chevy Chase, Maryland
| | - David G Hunter
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts; Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts.
| | - Elizabeth C Engle
- Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts; Department of Neurology, Boston Children's Hospital, Boston, Massachusetts; F. B. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts; Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts; Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts; Department of Neurology, Harvard Medical School, Boston, Massachusetts; Howard Hughes Medical Institute, Chevy Chase, Maryland.
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84
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Rucker JC, Webb BD, Frempong T, Gaspar H, Naidich TP, Jabs EW. Characterization of ocular motor deficits in congenital facial weakness: Moebius and related syndromes. ACTA ACUST UNITED AC 2014; 137:1068-79. [PMID: 24561559 DOI: 10.1093/brain/awu021] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Congenital facial weakness is present in a heterogeneous group of conditions. Among them is Moebius syndrome, which has been defined as a disorder with congenital, non-progressive facial weakness and limited abduction of one or both eyes. It is typically attributed to agenesis of the abducens and facial cranial nerves. This paper details ocular motor findings of 40 subjects (23 months to 64 years; 24 females, 16 males) with congenital facial weakness: 38 presented at a Moebius Syndrome Conference and two were clinic patients. A new classification scheme of patterns based on ocular motor phenotype is presented. Of 40 subjects, 37 had bilateral and three had unilateral facial weakness. The most common ocular motor pattern (Pattern 1, n=17, 43%) was bilateral horizontal gaze palsy with intact vertical range. Pattern 2 (n=10, 26%) was bilateral horizontal gaze palsy with variable vertical limitations. Pattern 3, which was rare, was isolated abduction deficits (n=2, 5%). Others had full motility range and did not meet minimal criteria for the diagnosis of Moebius syndrome (Pattern 4, n=10, 26%). One subject was too severely affected to characterize. Abnormal vertical smooth pursuit was present in 17 (57%) of 30 subjects: nine with Pattern 1, five with Pattern 2, and three with Pattern 4. Abnormal vertical saccades were present in 10 (34%) of 29 subjects. Vertical saccades appeared slow in nine: six with Pattern 1 and three with Pattern 2. Vertical saccades were absent in one subject with Pattern 2. Abnormal vertical optokinetic nystagmus was present in 19 (68%) of 28 subjects: 10 with Pattern 1, six with Pattern 2, one with Pattern 3, and two with Pattern 4. Reduced convergence was present in 19 (66%) of 29 subjects: nine with Pattern 1, six with Pattern 2, one with Pattern 3, and three with Pattern 4. The most common pattern of ocular motor deficit in Moebius syndrome is bilateral horizontal gaze palsy from pontine abducens nuclear defects, rather than abducens nerve involvement. Defects in the range or dynamic properties of vertical movements in subjects with congenital facial weakness may suggest involvement of ocular motor structures in the midbrain, including oculomotor nerves or nuclei, vertical supranuclear saccadic centres, and convergence neurons. Such deficits were found even in subjects with full vertical motility range. Classification of patterns of ocular motor deficits in congenital facial weakness may assist with further delineation of anatomic localization and identification of genetic deficits underlying these disorders.
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Affiliation(s)
- Janet C Rucker
- 1 Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
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Edwards TJ, Sherr EH, Barkovich AJ, Richards LJ. Clinical, genetic and imaging findings identify new causes for corpus callosum development syndromes. ACTA ACUST UNITED AC 2014; 137:1579-613. [PMID: 24477430 DOI: 10.1093/brain/awt358] [Citation(s) in RCA: 221] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The corpus callosum is the largest fibre tract in the brain, connecting the two cerebral hemispheres, and thereby facilitating the integration of motor and sensory information from the two sides of the body as well as influencing higher cognition associated with executive function, social interaction and language. Agenesis of the corpus callosum is a common brain malformation that can occur either in isolation or in association with congenital syndromes. Understanding the causes of this condition will help improve our knowledge of the critical brain developmental mechanisms required for wiring the brain and provide potential avenues for therapies for callosal agenesis or related neurodevelopmental disorders. Improved genetic studies combined with mouse models and neuroimaging have rapidly expanded the diverse collection of copy number variations and single gene mutations associated with callosal agenesis. At the same time, advances in our understanding of the developmental mechanisms involved in corpus callosum formation have provided insights into the possible causes of these disorders. This review provides the first comprehensive classification of the clinical and genetic features of syndromes associated with callosal agenesis, and provides a genetic and developmental framework for the interpretation of future research that will guide the next advances in the field.
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Affiliation(s)
- Timothy J Edwards
- 1 Queensland Brain Institute, The University of Queensland, Brisbane, 4072, Australia2 Departments of Neurology and Pediatrics, The University of California and the Benioff Children's Hospital, CA, 94158, USA
| | - Elliott H Sherr
- 3 Departments of Pediatrics and Neurosurgery, Radiology and Biomedical Imaging, The University of California Children's Hospital, CA 94143, USA
| | - A James Barkovich
- 3 Departments of Pediatrics and Neurosurgery, Radiology and Biomedical Imaging, The University of California Children's Hospital, CA 94143, USA4 Departments of Paediatrics and Neurosurgery, Radiology and Biomedical Imaging, The University of California San Francisco and The Benioff Children's Hospital, CA 94143-0628 USA
| | - Linda J Richards
- 1 Queensland Brain Institute, The University of Queensland, Brisbane, 4072, Australia5 School of Biomedical Sciences, The University of Queensland, Brisbane, 4072, Australia
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Breuss M, Keays DA. Microtubules and neurodevelopmental disease: the movers and the makers. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 800:75-96. [PMID: 24243101 DOI: 10.1007/978-94-007-7687-6_5] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The development of the mammalian cortex requires the generation, migration and differentiation of neurons. Each of these cellular events requires a dynamic microtubule cytoskeleton. Microtubules are required for interkinetic nuclear migration, the separation of chromatids in mitosis, nuclear translocation during migration and the outgrowth of neurites. Their importance is underlined by the finding that mutations in a host of microtubule associated proteins cause detrimental neurological disorders. More recently, the structural subunits of microtubules, the tubulin proteins, have been implicated in a spectrum of human diseases collectively known as the tubulinopathies. This chapter reviews the discovery of microtubules, the role they play in neurodevelopment, and catalogues the tubulin isoforms associated with neurodevelopmental disease. Our focus is on the molecular and cellular mechanisms that underlie the pathology of tubulin-associated diseases. Finally, we reflect on whether different tubulin genes have distinct intrinsic functions.
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Affiliation(s)
- Martin Breuss
- Institute of Molecular Pathology, Dr. Bohr-Gasse 7, 1030, Vienna, Austria
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87
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Bosley TM, Abu-Amero KK, Oystreck DT. Congenital cranial dysinnervation disorders. Curr Opin Ophthalmol 2013; 24:398-406. [DOI: 10.1097/icu.0b013e3283645ad6] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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88
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Affiliation(s)
- James Barkovich
- Department of Radiology, University of California at San Francisco, 505 Parnassus Avenue, San Francisco, CA 94143-0628, USA.
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