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Bernardo P, Cuccurullo C, Rubino M, De Vita G, Terrone G, Bilo L, Coppola A. X-Linked Epilepsies: A Narrative Review. Int J Mol Sci 2024; 25:4110. [PMID: 38612920 PMCID: PMC11012983 DOI: 10.3390/ijms25074110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 04/03/2024] [Accepted: 04/06/2024] [Indexed: 04/14/2024] Open
Abstract
X-linked epilepsies are a heterogeneous group of epileptic conditions, which often overlap with X-linked intellectual disability. To date, various X-linked genes responsible for epilepsy syndromes and/or developmental and epileptic encephalopathies have been recognized. The electro-clinical phenotype is well described for some genes in which epilepsy represents the core symptom, while less phenotypic details have been reported for other recently identified genes. In this review, we comprehensively describe the main features of both X-linked epileptic syndromes thoroughly characterized to date (PCDH19-related DEE, CDKL5-related DEE, MECP2-related disorders), forms of epilepsy related to X-linked neuronal migration disorders (e.g., ARX, DCX, FLNA) and DEEs associated with recently recognized genes (e.g., SLC9A6, SLC35A2, SYN1, ARHGEF9, ATP6AP2, IQSEC2, NEXMIF, PIGA, ALG13, FGF13, GRIA3, SMC1A). It is often difficult to suspect an X-linked mode of transmission in an epilepsy syndrome. Indeed, different models of X-linked inheritance and modifying factors, including epigenetic regulation and X-chromosome inactivation in females, may further complicate genotype-phenotype correlations. The purpose of this work is to provide an extensive and updated narrative review of X-linked epilepsies. This review could support clinicians in the genetic diagnosis and treatment of patients with epilepsy featuring X-linked inheritance.
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Affiliation(s)
- Pia Bernardo
- Pediatric Psychiatry and Neurology Unit, Department of Neurosciences, Santobono-Pausilipon Children’s Hospital, 80129 Naples, Italy
| | - Claudia Cuccurullo
- Neurology and Stroke Unit, Ospedale del Mare Hospital, ASL Napoli 1 Centro, 80147 Naples, Italy;
| | - Marica Rubino
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University Federico II of Naples, 80131 Naples, Italy (L.B.)
| | - Gabriella De Vita
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, 80131 Naples, Italy;
| | - Gaetano Terrone
- Child Neuropsychiatry Units, Department of Translational Medical Sciences, University Federico II of Naples, 80131 Naples, Italy;
| | - Leonilda Bilo
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University Federico II of Naples, 80131 Naples, Italy (L.B.)
| | - Antonietta Coppola
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University Federico II of Naples, 80131 Naples, Italy (L.B.)
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Zaker E, Nouri N, Movahedinia M, Dadbinpour A, Vahidi Mehrjardi MY. Type 1 early infantile epileptic encephalopathy: A case report and literature review. Mol Genet Genomic Med 2024; 12:e2412. [PMID: 38400608 PMCID: PMC10891437 DOI: 10.1002/mgg3.2412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 02/09/2024] [Accepted: 02/13/2024] [Indexed: 02/25/2024] Open
Abstract
BACKGROUND Variants in the Aristaless-related homeobox (ARX) gene lead to a variety of phenotypes, with intellectual disability being a steady feature. Other features can include severe epilepsy, spasticity, movement disorders, hydranencephaly, and ambiguous genitalia in males. X-linked Ohtahara syndrome or Type 1 early infantile epileptic encephalopathy (EIEE1) is a severe early-onset epileptic encephalopathy with arrested psychomotor development caused by hemizygous mutations in the ARX gene, which encodes a transcription factor in fundamental brain developmental processes. METHODS We presented a case report of a 2-year-old boy who exhibited symptoms such as microcephaly, seizures, and severe multifocal epileptic abnormalities, and genetic techniques such as autozygosity mapping, Sanger sequencing, and whole-exome sequencing. RESULTS We confirmed that the patient had the NM_139058.3:c.84C>A; p.(Cys28Ter) mutation in the ARX gene. CONCLUSION The patient with EIEE1 had physical symptoms and hypsarrhythmia on electroencephalogram. Genetic testing identified a causative mutation in the ARX gene, emphasizing the role of genetic testing in EIEE diagnosis.
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Affiliation(s)
- Erfan Zaker
- Department of Medical Genetics, Faculty of MedicineShahid Sadoughi University of Medical SciencesYazdIran
| | - Negar Nouri
- Department of Medical Genetics, Faculty of MedicineShahid Sadoughi University of Medical SciencesYazdIran
| | - Mojtaba Movahedinia
- Department of Children Growth Disorder Research CenterShahid Sadoughi University of Medical SciencesYazdIran
| | - Ali Dadbinpour
- Department of Medical GeneticsSchool of MedicineShahid Sadoughi University of Medical SciencesYazdIran
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Gras M, Heide S, Keren B, Valence S, Garel C, Whalen S, Jansen AC, Keymolen K, Stouffs K, Jennesson M, Poirsier C, Lesca G, Depienne C, Nava C, Rastetter A, Curie A, Cuisset L, Des Portes V, Milh M, Charles P, Mignot C, Héron D. Further characterisation of ARX-related disorders in females due to inherited or de novo variants. J Med Genet 2024; 61:103-108. [PMID: 37879892 DOI: 10.1136/jmg-2023-109203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 09/30/2023] [Indexed: 10/27/2023]
Abstract
The Aristaless-related homeobox (ARX) gene is located on the X chromosome and encodes a transcription factor that is essential for brain development. While the clinical spectrum of ARX-related disorders is well described in males, from X linked lissencephaly with abnormal genitalia syndrome to syndromic and non-syndromic intellectual disability (ID), its phenotypic delineation in females is incomplete. Carrier females in ARX families are usually asymptomatic, but ID has been reported in some of them, as well as in others with de novo variants. In this study, we collected the clinical and molecular data of 10 unpublished female patients with de novo ARX pathogenic variants and reviewed the data of 63 females from the literature with either de novo variants (n=10), inherited variants (n=33) or variants of unknown inheritance (n=20). Altogether, the clinical spectrum of females with heterozygous pathogenic ARX variants is broad: 42.5% are asymptomatic, 16.4% have isolated agenesis of the corpus callosum (ACC) or mild symptoms (learning disabilities, autism spectrum disorder, drug-responsive epilepsy) without ID, whereas 41% present with a severe phenotype (ie, ID or developmental and epileptic encephalopathy (DEE)). The ID/DEE phenotype was significantly more prevalent in females carrying de novo variants (75%, n=15/20) versus in those carrying inherited variants (27.3%, n=9/33). ACC was observed in 66.7% (n=24/36) of females who underwent a brain MRI. By refining the clinical spectrum of females carrying ARX pathogenic variants, we show that ID is a frequent sign in females with this X linked condition.
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Affiliation(s)
- Mathilde Gras
- Department of Clinical Genetics, APHP Sorbonne Université, University Hospital Pitié Salpêtrière, Paris, France
| | - Solveig Heide
- Department of Clinical Genetics, APHP Sorbonne Université, University Hospital Pitié Salpêtrière, Paris, France
- Reference Center for Rare Diseases « Intellectual disabilities of rare causes » Déficiences Intellectuelles de Causes Rares, University Hospital Pitié Salpêtrière, Paris, France
- Doctoral College, Sorbonne University, Paris, France
| | - Boris Keren
- Department of Clinical Genetics, APHP Sorbonne Université, University Hospital Pitié Salpêtrière, Paris, France
| | - Stéphanie Valence
- Unit of Pediatric Neurology, APHP Sorbonne Université, Armand-Trousseau Hospital, Paris, France
- Reference Center for Rare Diseases « Intellectual disabilites of rare causes » Déficiences Intellectuelles de Causes Rares, Armand-Trousseau Hospital, Paris, France
| | - Catherine Garel
- Unit of Pediatric Radiology, APHP Sorbonne Université, Armand-Trousseau Hospital, Paris, France
| | - Sandra Whalen
- Department of Clinical Genetics and Reference Center for Rare Diseases « Developmental disorders and syndromes », APHP Sorbonne Université, Armand-Trousseau Hospital, Paris, France
| | - Anna C Jansen
- Neurogenetics Research Group, Vrije Universiteit Brussel, Brussels, Belgium
| | - Kathelijn Keymolen
- Clinical Sciences, Research Group Reproduction and Genetics, Centre for Medical Genetics, Universitair Ziekenhuis Brussel (UZ Brussels), Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Katrien Stouffs
- Clinical Sciences, Research Group Reproduction and Genetics, Centre for Medical Genetics, Universitair Ziekenhuis Brussel (UZ Brussels), Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Mélanie Jennesson
- Pediatrics Unit, University Hospital of Reims, American Memorial Hospital, Reims, France
| | - Céline Poirsier
- UF génétique clinique, Pôle Femme-Parents-Enfants, CHU Reims, Reims, France
| | - Gaetan Lesca
- Department of Genetics, Referral Center for Developmental Anomalies and Malformative Syndromes, Centre-est HCL, Hospices Civils de Lyon, Lyon, France
| | - Christel Depienne
- Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | | | | | - Aurore Curie
- Reference Centre for Rare Diseases « Intellectual disabilities of rare causes », Civil Hospices of Lyon, Lyon, France
- University Lyon 1 Faculty of Medicine Lyon-Est, Lyon, France
| | - Laurence Cuisset
- APHP Centre Université Paris Cité, Service de Médecine Génomique des Maladies de Système et d'Organe, Cochin Hospital, Paris, France
| | - Vincent Des Portes
- Reference Centre for Rare Diseases « Intellectual disabilities of rare causes », Civil Hospices of Lyon, Lyon, France
- University Lyon 1 Faculty of Medicine Lyon-Est, Lyon, France
| | - Mathieu Milh
- Department of Neurology Pediatrics, AP-HM, Hôpital de la Timone, Marseille, France
| | - Perrine Charles
- Department of Clinical Genetics, APHP Sorbonne Université, University Hospital Pitié Salpêtrière, Paris, France
- Reference Center for Rare Diseases « Intellectual disabilities of rare causes » Déficiences Intellectuelles de Causes Rares, University Hospital Pitié Salpêtrière, Paris, France
| | - Cyril Mignot
- Department of Clinical Genetics, APHP Sorbonne Université, University Hospital Pitié Salpêtrière, Paris, France
- Reference Center for Rare Diseases « Intellectual disabilities of rare causes » Déficiences Intellectuelles de Causes Rares, University Hospital Pitié Salpêtrière, Paris, France
| | - Delphine Héron
- Department of Clinical Genetics, APHP Sorbonne Université, University Hospital Pitié Salpêtrière, Paris, France
- Reference Center for Rare Diseases « Intellectual disabilities of rare causes » Déficiences Intellectuelles de Causes Rares, University Hospital Pitié Salpêtrière, Paris, France
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Lim Y. Transcription factors in microcephaly. Front Neurosci 2023; 17:1302033. [PMID: 38094004 PMCID: PMC10716367 DOI: 10.3389/fnins.2023.1302033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 11/06/2023] [Indexed: 02/01/2024] Open
Abstract
Higher cognition in humans, compared to other primates, is often attributed to an increased brain size, especially forebrain cortical surface area. Brain size is determined through highly orchestrated developmental processes, including neural stem cell proliferation, differentiation, migration, lamination, arborization, and apoptosis. Disruption in these processes often results in either a small (microcephaly) or large (megalencephaly) brain. One of the key mechanisms controlling these developmental processes is the spatial and temporal transcriptional regulation of critical genes. In humans, microcephaly is defined as a condition with a significantly smaller head circumference compared to the average head size of a given age and sex group. A growing number of genes are identified as associated with microcephaly, and among them are those involved in transcriptional regulation. In this review, a subset of genes encoding transcription factors (e.g., homeobox-, basic helix-loop-helix-, forkhead box-, high mobility group box-, and zinc finger domain-containing transcription factors), whose functions are important for cortical development and implicated in microcephaly, are discussed.
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Affiliation(s)
- Youngshin Lim
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, United States
- Department of Biomedical Science Education, Charles R. Drew University of Medicine and Science, Los Angeles, CA, United States
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5
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Edey J, Soleimani-Nouri P, Dawson-Kavanagh A, Imran Azeem MS, Episkopou V. X-linked neuronal migration disorders: Gender differences and insights for genetic screening. Int J Dev Neurosci 2023; 83:581-599. [PMID: 37574439 DOI: 10.1002/jdn.10290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 06/23/2023] [Accepted: 07/14/2023] [Indexed: 08/15/2023] Open
Abstract
Cortical development depends on neuronal migration of both excitatory and inhibitory interneurons. Neuronal migration disorders (NMDs) are conditions characterised by anatomical cortical defects leading to varying degrees of neurocognitive impairment, developmental delay and seizures. Refractory epilepsy affects 15 million people worldwide, and it is thought that cortical developmental disorders are responsible for 25% of childhood cases. However, little is known about the epidemiology of these disorders, nor are their aetiologies fully understood, though many are associated with sporadic genetic mutations. In this review, we aim to highlight X-linked NMDs including lissencephaly, periventricular nodular heterotopia and polymicrogyria because of their mostly familial inheritance pattern. We focus on the most prominent genes responsible: including DCX, ARX, FLNA, FMR1, L1CAM, SRPX2, DDX3X, NSHDL, CUL4B and OFD1, outlining what is known about their prevalence among NMDs, and the underlying pathophysiology. X-linked disorders are important to recognise clinically, as females often have milder phenotypes. Consequently, there is a greater chance they survive to reproductive age and risk passing the mutations down. Effective genetic screening is important to prevent and treat these conditions, and for this, we need to know gene mutations and have a clear understanding of the function of the genes involved. This review summarises the knowledge base and provides clear direction for future work by both scientists and clinicians alike.
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Affiliation(s)
- Juliet Edey
- Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, London, UK
| | - Payam Soleimani-Nouri
- Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, London, UK
| | | | | | - Vasso Episkopou
- Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, London, UK
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6
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Devi R, Chaurasia S, Priyadarshi M, Singh P, Basu S. Proud Syndrome: A Rare Cause of Corpus Callosum Agenesis. Cureus 2023; 15:e40671. [PMID: 37485122 PMCID: PMC10357128 DOI: 10.7759/cureus.40671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/19/2023] [Indexed: 07/25/2023] Open
Abstract
Agenesis of the corpus callosum (ACC) is one of the most common congenital brain anomalies with variable associations and outcomes. The incidence of ACC varies from 1.8 per 10,000 live births in normal children to as high as 600 per 10,000 in children with neurodevelopmental problems. Here, we report the case of a female neonate delivered in our institute at term gestation to a gravida 4 mother with partial ACC. The neonate was antenatally diagnosed with ACC. The mother had a previous fetus with a supratentorial cyst that was medically terminated. The neonate had a normal clinical examination, but the ultrasound of the cranium suggested ACC. Given the significant family history, a clinical exome sequencing test revealed a pathogenic frameshift mutation in the ARX gene that causes Proud syndrome. We discuss the relevant points in the diagnosis, workup, and prognosis of ACC through this case. This case highlights the importance of antenatal assessment for timely amniocentesis and a genetic diagnosis to guide the parental decision for continuation of the pregnancy, level 2 scans to detect associated anomalies, and postnatal assessment to determine the cause and prognosis of a neonate with ACC.
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Affiliation(s)
- Risha Devi
- Neonatology, All India Institute of Medical Sciences, Rishikesh, Rishikesh, IND
| | - Suman Chaurasia
- Neonatology, All India Institute of Medical Sciences, Rishikesh, Rishikesh, IND
| | - Mayank Priyadarshi
- Neonatology, All India Institute of Medical Sciences, Rishikesh, Rishikesh, IND
| | - Poonam Singh
- Neonatology, All India Institute of Medical Sciences, Rishikesh, Rishikesh, IND
| | - Sriparna Basu
- Neonatology, All India Institute of Medical Sciences, Rishikesh, Rishikesh, IND
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7
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Kanduc D. Exposure to SARS-CoV-2 and Infantile Diseases. Glob Med Genet 2023; 10:72-78. [PMID: 37144240 PMCID: PMC10154082 DOI: 10.1055/s-0043-1768699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023] Open
Abstract
Background and Aim Immune response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in newborns and children after prophylactic immunization is currently a relevant research topic. The present study analyzes the issue by examining the possibility that the anti-SARS-CoV-2 immune responses are not uniquely directed against the virus but can-via molecular mimicry and the consequent cross-reactivity-also hit human proteins involved in infantile diseases. Methods Human proteins that-if altered-associate with infantile disorders were searched for minimal immune pentapeptide determinants shared with SARS-CoV-2 spike glycoprotein (gp). Then, the shared pentapeptides were analyzed for immunologic potential and immunologic imprinting phenomena. Results Comparative sequence analysis shows that: (1) numerous pentapeptides (namely, 54) are common to SARS-CoV-2 spike gp and human proteins that, when altered, are linked to infantile diseases; (2) all the shared peptides have an immunologic potential since they are present in experimentally validated SARS-CoV-2 spike gp-derived epitopes; and (3) many of the shared peptides are also hosted in infectious pathogens to which children can have already been exposed, thus making immunologic imprint phenomena feasible. Conclusion Molecular mimicry and the consequent cross-reactivity can represent the mechanism that connects exposure to SARS-CoV-2 and various pediatric diseases, with a fundamental role of the immunologic memory and the history of the child's infections in determining and specifying the immune response and the pathologic autoimmune sequela.
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Affiliation(s)
- Darja Kanduc
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
- Address for correspondence Darja Kanduc, PhD Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari70126 BariItaly
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8
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Babcock SJ, Flores-Marin D, Thiagarajah JR. The genetics of monogenic intestinal epithelial disorders. Hum Genet 2023; 142:613-654. [PMID: 36422736 PMCID: PMC10182130 DOI: 10.1007/s00439-022-02501-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 10/23/2022] [Indexed: 11/27/2022]
Abstract
Monogenic intestinal epithelial disorders, also known as congenital diarrheas and enteropathies (CoDEs), are a group of rare diseases that result from mutations in genes that primarily affect intestinal epithelial cell function. Patients with CoDE disorders generally present with infantile-onset diarrhea and poor growth, and often require intensive fluid and nutritional management. CoDE disorders can be classified into several categories that relate to broad areas of epithelial function, structure, and development. The advent of accessible and low-cost genetic sequencing has accelerated discovery in the field with over 45 different genes now associated with CoDE disorders. Despite this increasing knowledge in the causal genetics of disease, the underlying cellular pathophysiology remains incompletely understood for many disorders. Consequently, clinical management options for CoDE disorders are currently limited and there is an urgent need for new and disorder-specific therapies. In this review, we provide a general overview of CoDE disorders, including a historical perspective of the field and relationship to other monogenic disorders of the intestine. We describe the genetics, clinical presentation, and known pathophysiology for specific disorders. Lastly, we describe the major challenges relating to CoDE disorders, briefly outline key areas that need further study, and provide a perspective on the future genetic and therapeutic landscape.
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Affiliation(s)
- Stephen J Babcock
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children's Hospital, Harvard Medical School, Enders Rm 605, 300 Longwood Ave, Boston, MA, 02115, USA
| | - David Flores-Marin
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children's Hospital, Harvard Medical School, Enders Rm 605, 300 Longwood Ave, Boston, MA, 02115, USA
| | - Jay R Thiagarajah
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children's Hospital, Harvard Medical School, Enders Rm 605, 300 Longwood Ave, Boston, MA, 02115, USA.
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9
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Pânzaru MC, Popa S, Lupu A, Gavrilovici C, Lupu VV, Gorduza EV. Genetic heterogeneity in corpus callosum agenesis. Front Genet 2022; 13:958570. [PMID: 36246626 PMCID: PMC9562966 DOI: 10.3389/fgene.2022.958570] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 09/05/2022] [Indexed: 11/18/2022] Open
Abstract
The corpus callosum is the largest white matter structure connecting the two cerebral hemispheres. Agenesis of the corpus callosum (ACC), complete or partial, is one of the most common cerebral malformations in humans with a reported incidence ranging between 1.8 per 10,000 livebirths to 230–600 per 10,000 in children and its presence is associated with neurodevelopmental disability. ACC may occur as an isolated anomaly or as a component of a complex disorder, caused by genetic changes, teratogenic exposures or vascular factors. Genetic causes are complex and include complete or partial chromosomal anomalies, autosomal dominant, autosomal recessive or X-linked monogenic disorders, which can be either de novo or inherited. The extreme genetic heterogeneity, illustrated by the large number of syndromes associated with ACC, highlight the underlying complexity of corpus callosum development. ACC is associated with a wide spectrum of clinical manifestations ranging from asymptomatic to neonatal death. The most common features are epilepsy, motor impairment and intellectual disability. The understanding of the genetic heterogeneity of ACC may be essential for the diagnosis, developing early intervention strategies, and informed family planning. This review summarizes our current understanding of the genetic heterogeneity in ACC and discusses latest discoveries.
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Affiliation(s)
- Monica-Cristina Pânzaru
- Department of Medical Genetics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, Iasi, Romania
| | - Setalia Popa
- Department of Medical Genetics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, Iasi, Romania
- *Correspondence: Setalia Popa, ; Vasile Valeriu Lupu,
| | - Ancuta Lupu
- Department of Pediatrics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, Iasi, Romania
| | - Cristina Gavrilovici
- Department of Pediatrics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, Iasi, Romania
| | - Vasile Valeriu Lupu
- Department of Pediatrics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, Iasi, Romania
- *Correspondence: Setalia Popa, ; Vasile Valeriu Lupu,
| | - Eusebiu Vlad Gorduza
- Department of Medical Genetics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, Iasi, Romania
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Inoue Y, Machida O, Kita Y, Yamamoto T. Need for revision of the ACMG/AMP guidelines for interpretation of X-linked variants. Intractable Rare Dis Res 2022; 11:120-124. [PMID: 36200025 PMCID: PMC9437996 DOI: 10.5582/irdr.2022.01067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 07/27/2022] [Accepted: 08/04/2022] [Indexed: 11/05/2022] Open
Abstract
The guidelines provided by American College of Medical Genetics and Genomics (ACMG) and the Association of Molecular Pathology (AMP) (ACMG/AMP guidelines) suggest a framework for the classification of clinical variants. However, the interpretations can be inconsistent, with each definition sometimes proving to be ambiguous. In particular, there can be difficulty with interpretation of variants related to the X-linked recessive trait. To confirm whether there are biases in the interpretation of inherited traits, we reanalyzed variants reported prior to the release of the ACMG/AMP guidelines. As expected, the interpretation ratio as pathogenic or likely pathogenic was significantly lower for variants related to the X-linked recessive trait. Evaluation of variants related to the X-linked recessive trait, hence, need to consider whether the variant is identified only in males in accordance with the X-linked recessive trait. The ACMG/AMP guidelines should be revised to eliminate the bias revealed in this study.
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Affiliation(s)
- Yoko Inoue
- Division of Gene Medicine, Graduate School of Medical Science, Tokyo Women's Medical University, Tokyo, Japan
- Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, Japan
| | - Osamu Machida
- Division of Gene Medicine, Graduate School of Medical Science, Tokyo Women's Medical University, Tokyo, Japan
- Department of Pediatrics, Tokyo Women's Medical University, Tokyo, Japan
| | - Yosuke Kita
- Department of Psychology, Faculty of Letters, Keio University, Tokyo, Japan
| | - Toshiyuki Yamamoto
- Division of Gene Medicine, Graduate School of Medical Science, Tokyo Women's Medical University, Tokyo, Japan
- Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, Japan
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11
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Drongitis D, Caterino M, Verrillo L, Santonicola P, Costanzo M, Poeta L, Attianese B, Barra A, Terrone G, Lioi MB, Paladino S, Di Schiavi E, Costa V, Ruoppolo M, Miano MG. Deregulation of microtubule organization and RNA metabolism in Arx models for lissencephaly and developmental epileptic encephalopathy. Hum Mol Genet 2022; 31:1884-1908. [PMID: 35094084 PMCID: PMC9169459 DOI: 10.1093/hmg/ddac028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 01/10/2022] [Accepted: 01/26/2022] [Indexed: 11/18/2022] Open
Abstract
X-linked lissencephaly with abnormal genitalia (XLAG) and developmental epileptic encephalopathy-1 (DEE1) are caused by mutations in the Aristaless-related homeobox (ARX) gene, which encodes a transcription factor responsible for brain development. It has been unknown whether the phenotypically diverse XLAG and DEE1 phenotypes may converge on shared pathways. To address this question, a label-free quantitative proteomic approach was applied to the neonatal brain of Arx knockout (ArxKO/Y) and knock-in polyalanine (Arx(GCG)7/Y) mice that are respectively models for XLAG and DEE1. Gene ontology and protein-protein interaction analysis revealed that cytoskeleton, protein synthesis and splicing control are deregulated in an allelic-dependent manner. Decreased α-tubulin content was observed both in Arx mice and Arx/alr-1(KO) Caenorhabditis elegans ,and a disorganized neurite network in murine primary neurons was consistent with an allelic-dependent secondary tubulinopathy. As distinct features of Arx(GCG)7/Y mice, we detected eIF4A2 overexpression and translational suppression in cortex and primary neurons. Allelic-dependent differences were also established in alternative splicing (AS) regulated by PUF60 and SAM68. Abnormal AS repertoires in Neurexin-1, a gene encoding multiple pre-synaptic organizers implicated in synaptic remodelling, were detected in Arx/alr-1(KO) animals and in Arx(GCG)7/Y epileptogenic brain areas and depolarized cortical neurons. Consistent with a conserved role of ARX in modulating AS, we propose that the allelic-dependent secondary synaptopathy results from an aberrant Neurexin-1 repertoire. Overall, our data reveal alterations mirroring the overlapping and variant effects caused by null and polyalanine expanded mutations in ARX. The identification of these effects can aid in the design of pathway-guided therapy for ARX endophenotypes and NDDs with overlapping comorbidities.
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Affiliation(s)
- Denise Drongitis
- Institute of Genetics and Biophysics ``Adriano Buzzati-Traverso'', National Research Council of Italy, 80131, Naples, Italy
| | - Marianna Caterino
- Department of Molecular Medicine and Medical Biotechnology, University of Naples “Federico II”, 80131 Naples, Italy
- CEINGE - Biotecnologie Avanzate s.c.a.r.l., 80145 Naples, Italy
| | - Lucia Verrillo
- Institute of Genetics and Biophysics ``Adriano Buzzati-Traverso'', National Research Council of Italy, 80131, Naples, Italy
| | - Pamela Santonicola
- Institute of Biosciences and BioResources, National Research Council of Italy, 80131, Naples, Italy
| | - Michele Costanzo
- Department of Molecular Medicine and Medical Biotechnology, University of Naples “Federico II”, 80131 Naples, Italy
- CEINGE - Biotecnologie Avanzate s.c.a.r.l., 80145 Naples, Italy
| | - Loredana Poeta
- Institute of Genetics and Biophysics ``Adriano Buzzati-Traverso'', National Research Council of Italy, 80131, Naples, Italy
- Department of Science, University of Basilicata, 85100 Potenza, Italy
| | - Benedetta Attianese
- Institute of Genetics and Biophysics ``Adriano Buzzati-Traverso'', National Research Council of Italy, 80131, Naples, Italy
| | - Adriano Barra
- Institute of Genetics and Biophysics ``Adriano Buzzati-Traverso'', National Research Council of Italy, 80131, Naples, Italy
| | - Gaetano Terrone
- Department of Translational Medicine, Child Neurology Unit, University of Naples “Federico II”, 80131 Naples, Italy
| | | | - Simona Paladino
- Department of Molecular Medicine and Medical Biotechnology, University of Naples “Federico II”, 80131 Naples, Italy
| | - Elia Di Schiavi
- Institute of Biosciences and BioResources, National Research Council of Italy, 80131, Naples, Italy
| | - Valerio Costa
- Institute of Genetics and Biophysics ``Adriano Buzzati-Traverso'', National Research Council of Italy, 80131, Naples, Italy
| | - Margherita Ruoppolo
- Department of Molecular Medicine and Medical Biotechnology, University of Naples “Federico II”, 80131 Naples, Italy
- CEINGE - Biotecnologie Avanzate s.c.a.r.l., 80145 Naples, Italy
| | - Maria Giuseppina Miano
- Institute of Genetics and Biophysics ``Adriano Buzzati-Traverso'', National Research Council of Italy, 80131, Naples, Italy
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12
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Lim Y, Cho IT, Golden JA, Cho G. Generation of FLAG-tagged Arx knock-in mouse model. Genesis 2022; 60:e23479. [PMID: 35656878 PMCID: PMC9333336 DOI: 10.1002/dvg.23479] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 05/11/2022] [Accepted: 05/11/2022] [Indexed: 11/06/2022]
Abstract
The Aristaless-related homeobox (ARX) is a paired-like homeodomain transcription factor playing important roles in brain development. Patients with mutations in ARX have a spectrum of neurodevelopmental disorders such as epilepsy, intellectual disability, and autism spectrum disorder, with or without structural abnormalities of the brain such as lissencephaly (smooth brain), microcephaly (small brain), and/or agenesis of the corpus callosum. Mouse models have provided important clues on the pathophysiologic roles of ARX in these disorders. However, successfully isolating specific in vivo complexes of ARX, with DNA and proteins, has remained as a challenge. To facilitate in vivo detection of ARX complexes, we generated a mouse line containing one epitope of FLAG-tag (1 × FLAG) targeted at the translational start site of the endogenous Arx gene using CRSPR/Cas9 strategy. Homozygous Flag-Arx mice are viable and fertile without gross abnormality, suggesting that the FLAG-tag does not perturb the normal function of ARX. Using a FLAG antibody, we successfully detected ARX with immunofluorescent staining and pulled down ARX in embryonic brain tissues. This Flag-Arx mouse line will be a useful tool to isolate ARX complexes from mouse tissues for many applications.
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Affiliation(s)
- Youngshin Lim
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Il-Taeg Cho
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Jeffrey A Golden
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Ginam Cho
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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13
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Leung RF, George AM, Roussel EM, Faux MC, Wigle JT, Eisenstat DD. Genetic Regulation of Vertebrate Forebrain Development by Homeobox Genes. Front Neurosci 2022; 16:843794. [PMID: 35546872 PMCID: PMC9081933 DOI: 10.3389/fnins.2022.843794] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 03/14/2022] [Indexed: 01/19/2023] Open
Abstract
Forebrain development in vertebrates is regulated by transcription factors encoded by homeobox, bHLH and forkhead gene families throughout the progressive and overlapping stages of neural induction and patterning, regional specification and generation of neurons and glia from central nervous system (CNS) progenitor cells. Moreover, cell fate decisions, differentiation and migration of these committed CNS progenitors are controlled by the gene regulatory networks that are regulated by various homeodomain-containing transcription factors, including but not limited to those of the Pax (paired), Nkx, Otx (orthodenticle), Gsx/Gsh (genetic screened), and Dlx (distal-less) homeobox gene families. This comprehensive review outlines the integral role of key homeobox transcription factors and their target genes on forebrain development, focused primarily on the telencephalon. Furthermore, links of these transcription factors to human diseases, such as neurodevelopmental disorders and brain tumors are provided.
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Affiliation(s)
- Ryan F. Leung
- Murdoch Children’s Research Institute, The Royal Children’s Hospital Melbourne, Parkville, VIC, Australia
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
| | - Ankita M. George
- Murdoch Children’s Research Institute, The Royal Children’s Hospital Melbourne, Parkville, VIC, Australia
| | - Enola M. Roussel
- Murdoch Children’s Research Institute, The Royal Children’s Hospital Melbourne, Parkville, VIC, Australia
| | - Maree C. Faux
- Murdoch Children’s Research Institute, The Royal Children’s Hospital Melbourne, Parkville, VIC, Australia
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
- Department of Surgery, Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia
| | - Jeffrey T. Wigle
- Department of Biochemistry and Medical Genetics, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada
| | - David D. Eisenstat
- Murdoch Children’s Research Institute, The Royal Children’s Hospital Melbourne, Parkville, VIC, Australia
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada
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14
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Stefano MED, Ferretti V, Mozzetta C. Synaptic alterations as a neurodevelopmental trait of Duchenne muscular dystrophy. Neurobiol Dis 2022; 168:105718. [PMID: 35390481 DOI: 10.1016/j.nbd.2022.105718] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 03/28/2022] [Accepted: 03/29/2022] [Indexed: 01/14/2023] Open
Abstract
Dystrophinopaties, e.g., Duchenne muscular dystrophy (DMD), Becker muscular dystrophy and X-linked dilated cardiomyopathy are inherited neuromuscular diseases, characterized by progressive muscular degeneration, which however associate with a significant impact on general system physiology. The more severe is the pathology and its diversified manifestations, the heavier are its effects on organs, systems, and tissues other than muscles (skeletal, cardiac and smooth muscles). All dystrophinopaties are characterized by mutations in a single gene located on the X chromosome encoding dystrophin (Dp427) and its shorter isoforms, but DMD is the most devasting: muscular degenerations manifests within the first 4 years of life, progressively affecting motility and other muscular functions, and leads to a fatal outcome between the 20s and 40s. To date, after years of studies on both DMD patients and animal models of the disease, it has been clearly demonstrated that a significant percentage of DMD patients are also afflicted by cognitive, neurological, and autonomic disorders, of varying degree of severity. The anatomical correlates underlying neural functional damages are established during embryonic development and the early stages of postnatal life, when brain circuits, sensory and motor connections are still maturing. The impact of the absence of Dp427 on the development, differentiation, and consolidation of specific cerebral circuits (hippocampus, cerebellum, prefrontal cortex, amygdala) is significant, and amplified by the frequent lack of one or more of its lower molecular mass isoforms. The most relevant aspect, which characterizes DMD-associated neurological disorders, is based on morpho-functional alterations of selective synaptic connections within the affected brain areas. This pathological feature correlates neurological conditions of DMD to other severe neurological disorders, such as schizophrenia, epilepsy and autistic spectrum disorders, among others. This review discusses the organization and the role of the dystrophin-dystroglycan complex in muscles and neurons, focusing on the neurological aspect of DMD and on the most relevant morphological and functional synaptic alterations, in both central and autonomic nervous systems, described in the pathology and its animal models.
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Affiliation(s)
- Maria Egle De Stefano
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, 00185 Rome, Italy; Center for Research in Neurobiology Daniel Bovet, Sapienza University of Rome, 00185 Rome, Italy.
| | - Valentina Ferretti
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, 00185 Rome, Italy; Center for Research in Neurobiology Daniel Bovet, Sapienza University of Rome, 00185 Rome, Italy
| | - Chiara Mozzetta
- Institute of Molecular Biology and Pathology (IBPM), National Research Council (CNR) of Italy c/o Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, 00185 Rome, Italy
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15
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Fischer J, Di Donato N. Diagnostic pitfalls in patients with malformations of cortical development. Eur J Paediatr Neurol 2022; 37:123-128. [PMID: 35228169 DOI: 10.1016/j.ejpn.2022.01.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 01/25/2022] [Accepted: 01/26/2022] [Indexed: 11/27/2022]
Abstract
Malformations of cortical development (MCDs) are a major source of morbidity and mortality in the pediatric patient cohort. Correct diagnosis of the cause is essential for symptom management, disease prognosis and family counselling but is frequently hampered due to numerous potential pitfalls in the diagnostic process. This review highlights potential problems that either prevent the establishment of a diagnosis or are the sources of diagnostic errors. The focus is placed on hereditary causes of MCDs and strategies will be proposed to circumvent potential diagnostic pitfalls. Errors may occur during variant detection, filtering, or interpretation in relation to patient's phenotype. Based on detailed clinical assessment suitable targeted and untargeted methods to identify pathogenic variants with context-dependent filtering and evaluation approaches will be discussed.
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Affiliation(s)
- Jan Fischer
- Institute for Clinical Genetics, University Hospital, TU Dresden, Dresden, Germany
| | - Nataliya Di Donato
- Institute for Clinical Genetics, University Hospital, TU Dresden, Dresden, Germany.
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16
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Loureiro JR, Castro AF, Figueiredo AS, Silveira I. Molecular Mechanisms in Pentanucleotide Repeat Diseases. Cells 2022; 11:cells11020205. [PMID: 35053321 PMCID: PMC8773600 DOI: 10.3390/cells11020205] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 01/04/2022] [Accepted: 01/05/2022] [Indexed: 02/01/2023] Open
Abstract
The number of neurodegenerative diseases resulting from repeat expansion has increased extraordinarily in recent years. In several of these pathologies, the repeat can be transcribed in RNA from both DNA strands producing, at least, one toxic RNA repeat that causes neurodegeneration by a complex mechanism. Recently, seven diseases have been found caused by a novel intronic pentanucleotide repeat in distinct genes encoding proteins highly expressed in the cerebellum. These disorders are clinically heterogeneous being characterized by impaired motor function, resulting from ataxia or epilepsy. The role that apparently normal proteins from these mutant genes play in these pathologies is not known. However, recent advances in previously known spinocerebellar ataxias originated by abnormal non-coding pentanucleotide repeats point to a gain of a toxic function by the pathogenic repeat-containing RNA that abnormally forms nuclear foci with RNA-binding proteins. In cells, RNA foci have been shown to be formed by phase separation. Moreover, the field of repeat expansions has lately achieved an extraordinary progress with the discovery that RNA repeats, polyglutamine, and polyalanine proteins are crucial for the formation of nuclear membraneless organelles by phase separation, which is perturbed when they are expanded. This review will cover the amazing advances on repeat diseases.
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Affiliation(s)
- Joana R. Loureiro
- Genetics of Cognitive Dysfunction Laboratory, i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (J.R.L.); (A.F.C.); (A.S.F.)
- Institute for Molecular and Cell Biology, Universidade do Porto, 4200-135 Porto, Portugal
| | - Ana F. Castro
- Genetics of Cognitive Dysfunction Laboratory, i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (J.R.L.); (A.F.C.); (A.S.F.)
- Institute for Molecular and Cell Biology, Universidade do Porto, 4200-135 Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, 4050-313 Porto, Portugal
| | - Ana S. Figueiredo
- Genetics of Cognitive Dysfunction Laboratory, i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (J.R.L.); (A.F.C.); (A.S.F.)
- Institute for Molecular and Cell Biology, Universidade do Porto, 4200-135 Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, 4050-313 Porto, Portugal
| | - Isabel Silveira
- Genetics of Cognitive Dysfunction Laboratory, i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (J.R.L.); (A.F.C.); (A.S.F.)
- Institute for Molecular and Cell Biology, Universidade do Porto, 4200-135 Porto, Portugal
- Correspondence: ; Tel.: +351-2240-8800
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17
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Koenig M, Dobyns WB, Di Donato N. Lissencephaly: Update on diagnostics and clinical management. Eur J Paediatr Neurol 2021; 35:147-152. [PMID: 34731701 DOI: 10.1016/j.ejpn.2021.09.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 08/30/2021] [Accepted: 09/03/2021] [Indexed: 11/27/2022]
Abstract
Lissencephaly represents a spectrum of rare malformations of cortical development including agyria, pachygyria and subcortical band heterotopia. The progress in molecular genetics has led to identification of 31 lissencephaly-associated genes with the overall diagnostic yield over 80%. In this review, we focus on clinical and molecular diagnosis of lissencephaly and summarize the current knowledge on histopathological changes and their correlation with the MRI imaging. Additionally we provide the overview of clinical follow-up recommendations and available data on epilepsy management in patients with lissencephaly.
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Affiliation(s)
- Matti Koenig
- Institute for Clinical Genetics, University Hospital, TU Dresden, Dresden, Germany
| | - William B Dobyns
- Department of Pediatrics (Genetics), University of Minnesota, Minneapolis, MN, USA
| | - Nataliya Di Donato
- Institute for Clinical Genetics, University Hospital, TU Dresden, Dresden, Germany.
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18
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Rodgers J, Calvert S, Shoubridge C, McGaughran J. A novel ARX loss of function variant in female monozygotic twins is associated with chorea. Eur J Med Genet 2021; 64:104315. [PMID: 34419634 DOI: 10.1016/j.ejmg.2021.104315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 06/29/2021] [Accepted: 08/18/2021] [Indexed: 10/20/2022]
Abstract
Pathogenic variants in ARX lead to a variety of phenotypes with intellectual disability being a uniform feature. Other features can include severe epilepsy, spasticity, movement disorders, agenesis of the corpus callosum, lissencephaly, hydranencephaly and ambiguous genitalia in males. We present the first report of monozygotic female twins with a de novo ARX pathogenic variant (c.1406_1415del; p. Ala469Aspfs*20), predicted to result in a truncated ARX protein missing the important regulatory Aristaless domain. The twins presented with profound developmental delay and seizures, consistent with the known genotype-phenotype correlation. Twin 2's features were significantly more severe. She also developed chorea; the first time this movement disorder has been seen in an ARX variant other than an expansion of the first polyalanine tract. Differential X-chromosome inactivation was the most likely explanation for the differing severities but could not be conclusively proven.
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Affiliation(s)
- Jonathan Rodgers
- Genetic Health Queensland, Royal Brisbane and Women's Hospital, QLD, Australia; School of Medicine, The University of Queensland, Brisbane, QLD, Australia.
| | - Sophie Calvert
- Department of Neurosciences, Queensland Children's Hospital, Brisbane, QLD, Australia; School of Medicine, The University of Queensland, Brisbane, QLD, Australia
| | - Cheryl Shoubridge
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia; Robinson Research Institute, University of Adelaide, Adelaide, South Australia, Australia
| | - Julie McGaughran
- Genetic Health Queensland, Royal Brisbane and Women's Hospital, QLD, Australia; School of Medicine, The University of Queensland, Brisbane, QLD, Australia
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19
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Poeta L, Padula A, Lioi MB, van Bokhoven H, Miano MG. Analysis of a Set of KDM5C Regulatory Genes Mutated in Neurodevelopmental Disorders Identifies Temporal Coexpression Brain Signatures. Genes (Basel) 2021; 12:genes12071088. [PMID: 34356104 PMCID: PMC8305412 DOI: 10.3390/genes12071088] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/13/2021] [Accepted: 07/15/2021] [Indexed: 12/22/2022] Open
Abstract
Dysregulation of transcriptional pathways is observed in multiple forms of neurodevelopmental disorders (NDDs), such as intellectual disability (ID), epilepsy and autism spectrum disorder (ASD). We previously demonstrated that the NDD genes encoding lysine-specific demethylase 5C (KDM5C) and its transcriptional regulators Aristaless related-homeobox (ARX), PHD Finger Protein 8 (PHF8) and Zinc Finger Protein 711 (ZNF711) are functionally connected. Here, we show their relation to each other with respect to the expression levels in human and mouse datasets and in vivo mouse analysis indicating that the coexpression of these syntenic X-chromosomal genes is temporally regulated in brain areas and cellular sub-types. In co-immunoprecipitation assays, we found that the homeotic transcription factor ARX interacts with the histone demethylase PHF8, indicating that this transcriptional axis is highly intersected. Furthermore, the functional impact of pathogenic mutations of ARX, KDM5C, PHF8 and ZNF711 was tested in lymphoblastoid cell lines (LCLs) derived from children with varying levels of syndromic ID establishing the direct correlation between defects in the KDM5C-H3K4me3 pathway and ID severity. These findings reveal novel insights into epigenetic processes underpinning NDD pathogenesis and provide new avenues for assessing developmental timing and critical windows for potential treatments.
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Affiliation(s)
- Loredana Poeta
- Institute of Genetics and Biophysics Adriano Buzzati-Traverso, CNR, 80131 Naples, Italy;
- Department of Science, University of Basilicata, 85100 Potenza, Italy;
- Correspondence: (L.P.); (M.G.M.); Tel.: +39-(0)-816132261/445 (M.G.M.)
| | - Agnese Padula
- Institute of Genetics and Biophysics Adriano Buzzati-Traverso, CNR, 80131 Naples, Italy;
| | | | - Hans van Bokhoven
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboudumc, 6525 GA Nijmegen, The Netherlands;
| | - Maria Giuseppina Miano
- Institute of Genetics and Biophysics Adriano Buzzati-Traverso, CNR, 80131 Naples, Italy;
- Correspondence: (L.P.); (M.G.M.); Tel.: +39-(0)-816132261/445 (M.G.M.)
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20
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Scalia B, Venti V, Ciccia LM, Criscione R, Lo Bianco M, Sciuto L, Falsaperla R, Zanghì A, Praticò AD. Aristaless-Related Homeobox (ARX): Epilepsy Phenotypes beyond Lissencephaly and Brain Malformations. JOURNAL OF PEDIATRIC NEUROLOGY 2021. [DOI: 10.1055/s-0041-1727140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
AbstractThe Aristaless-related homeobox (ARX) transcription factor is involved in the development of GABAergic and cholinergic neurons in the forebrain. ARX mutations have been associated with a wide spectrum of neurodevelopmental disorders in humans and are responsible for both malformation (in particular lissencephaly) and nonmalformation complex phenotypes. The epilepsy phenotypes related to ARX mutations are West syndrome and X-linked infantile spasms, X-linked myoclonic epilepsy with spasticity and intellectual development and Ohtahara and early infantile epileptic encephalopathy syndrome, which are related in most of the cases to intellectual disability and are often drug resistant. In this article, we shortly reviewed current knowledge of the function of ARX with a particular attention on its consequences in the development of epilepsy during early childhood.
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Affiliation(s)
- Bruna Scalia
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Valeria Venti
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Lina M. Ciccia
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Roberta Criscione
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Manuela Lo Bianco
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Laura Sciuto
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Raffaele Falsaperla
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
- Neonatal Intensive Care unit and Neonatology, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| | - Antonio Zanghì
- Department of Medical and Surgical Sciences and Advanced Technology “G.F. Ingrassia,” University of Catania, Catania, Italy
| | - Andrea D. Praticò
- Unit of Rare Diseases of the Nervous System in Childhood, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
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21
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Benmakhlouf Y, Touraine R, Harzallah I, Zian Z, Ben Makhlouf K, Barakat A, Ghailani Nourouti N, Bennani Mechita M. Screening of the duplication 24 pb of ARX gene in Moroccan patients with X-linked Intellectual Disability. BMC Res Notes 2021; 14:110. [PMID: 33757564 PMCID: PMC7988900 DOI: 10.1186/s13104-021-05526-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 03/13/2021] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVE Intellectual Disability (ID) represents a neuropsychiatric disorder, which its etiopathogenesis remains insufficiently understood. Mutations in the Aristaless Related Homeobox gene (ARX) have been identified to cause syndromic and nonsyndromic (NS-ID). The most recurrent mutation of this gene is a duplication of 24pb, c.428-451dup. Epidemiological and genetic studies about ID in the Moroccan population remain very scarce, and none study is carried out on the ARX gene. This work aimed to study c.428-451dup (24 bp) mutation in the exon 2 of the ARX gene in 118 males' Moroccan patients with milder NS-ID to evaluate if the gene screening is a good tool for identifying NS-ID. RESULTS Our mutational analysis did not show any dup(24pb) in our patients. This is because based on findings from previous studies that found ARX mutations in 70% of families with NS-ID, and in most cases, 1.5-6.1% of individuals with NS-ID have this duplication. Since 1/118 = 0.0084 (0.84%) is not much different from 1.5%, then it is reasonable that this could a sample size artifact. A complete screening of the entire ARX gene, including the five exons, should be fulfilled. Further investigations are required to confirm these results.
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Affiliation(s)
- Yousra Benmakhlouf
- Biomedical Genomics and Oncogenetics Research Laboratory, Faculty of Sciences and Techniques of Tangier, University Abdelmalek Essaadi, P.B.:416, Tangier, Morocco.
| | | | - Ines Harzallah
- Molecular Genetics Laboratory, CHU, Saint Etienne, France
| | - Zeineb Zian
- Biomedical Genomics and Oncogenetics Research Laboratory, Faculty of Sciences and Techniques of Tangier, University Abdelmalek Essaadi, P.B.:416, Tangier, Morocco
| | | | - Amina Barakat
- Biomedical Genomics and Oncogenetics Research Laboratory, Faculty of Sciences and Techniques of Tangier, University Abdelmalek Essaadi, P.B.:416, Tangier, Morocco
| | - Naima Ghailani Nourouti
- Biomedical Genomics and Oncogenetics Research Laboratory, Faculty of Sciences and Techniques of Tangier, University Abdelmalek Essaadi, P.B.:416, Tangier, Morocco
| | - Mohcine Bennani Mechita
- Biomedical Genomics and Oncogenetics Research Laboratory, Faculty of Sciences and Techniques of Tangier, University Abdelmalek Essaadi, P.B.:416, Tangier, Morocco
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22
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Mazen I, Mekkawy M, Kamel A, Essawi M, Hassan H, Abdel-Hamid M, Amr K, Soliman H, El-Ruby M, Torky A, El Gammal M, Elaidy A, Bashamboo A, McElreavey K. Advances in genomic diagnosis of a large cohort of Egyptian patients with disorders of sex development. Am J Med Genet A 2021; 185:1666-1677. [PMID: 33742552 DOI: 10.1002/ajmg.a.62129] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 01/28/2021] [Accepted: 01/30/2021] [Indexed: 12/15/2022]
Abstract
Disorders/differences of sex development (DSD) comprise a group of congenital disorders that affect the genitourinary tract and usually involve the endocrine and reproductive system. The aim of this work was to identify genetic variants responsible for disorders of human urogenital development in a cohort of Egyptian patients. This three-year study included 225 patients with various DSD forms, referred to the genetic DSD and endocrinology clinic, National Research Centre, Egypt. The patients underwent thorough clinical examination, hormonal and imaging studies, detailed cytogenetic and fluorescence in situ hybridization analysis, and molecular sequencing of genes known to commonly cause DSD including AR, SRD5A2, 17BHSD3, NR5A1, SRY, and WT1. Whole exome sequencing (WES) was carried out for 18 selected patients. The study revealed a high rate of sex chromosomal DSD (33%) with a wide array of cytogenetic abnormalities. Sanger sequencing identified pathogenic variants in 33.7% of 46,XY patients, while the detection rate of WES reached 66.7%. Our patients showed a different mutational profile compared with that reported in other populations with a predominance of heritable DSD causes. WES identified rare and novel pathogenic variants in NR5A1, WT1, HHAT, CYP19A1, AMH, AMHR2, and FANCA and in the X-linked genes ARX and KDM6A. In addition, digenic inheritance was observed in two of our patients and was suggested to be a cause of the phenotypic variability observed in DSD.
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Affiliation(s)
- Inas Mazen
- Department of Clinical Genetics, National Research Centre, Cairo, Egypt
| | - Mona Mekkawy
- Department of Human Cytogenetics, National Research Center, Cairo, Egypt
| | - Alaa Kamel
- Department of Human Cytogenetics, National Research Center, Cairo, Egypt
| | - Mona Essawi
- Department of Medical Molecular Genetics, National Research Centre, Cairo, Egypt
| | - Heba Hassan
- Department of Medical Molecular Genetics, National Research Centre, Cairo, Egypt
| | - Mohamed Abdel-Hamid
- Department of Medical Molecular Genetics, National Research Centre, Cairo, Egypt
| | - Khalda Amr
- Department of Medical Molecular Genetics, National Research Centre, Cairo, Egypt
| | - Hala Soliman
- Department of Medical Molecular Genetics, National Research Centre, Cairo, Egypt
| | - Mona El-Ruby
- Department of Clinical Genetics, National Research Centre, Cairo, Egypt
| | - Ahmed Torky
- Department of Clinical Genetics, National Research Centre, Cairo, Egypt
| | - Mona El Gammal
- Department of Clinical Genetics, National Research Centre, Cairo, Egypt
| | - Aya Elaidy
- Department of Clinical Genetics, National Research Centre, Cairo, Egypt
| | - Anu Bashamboo
- Developmental Genetics and Stem Cell Biology, Institut Pasteur, Paris, France
| | - Kenneth McElreavey
- Developmental Genetics and Stem Cell Biology, Institut Pasteur, Paris, France
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23
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Mechanisms of repeat-associated non-AUG translation in neurological microsatellite expansion disorders. Biochem Soc Trans 2021; 49:775-792. [PMID: 33729487 PMCID: PMC8106499 DOI: 10.1042/bst20200690] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 02/20/2021] [Accepted: 02/23/2021] [Indexed: 02/08/2023]
Abstract
Repeat-associated non-AUG (RAN) translation was discovered in 2011 in spinocerebellar ataxia type 8 (SCA8) and myotonic dystrophy type 1 (DM1). This non-canonical form of translation occurs in all reading frames from both coding and non-coding regions of sense and antisense transcripts carrying expansions of trinucleotide to hexanucleotide repeat sequences. RAN translation has since been reported in 7 of the 53 known microsatellite expansion disorders which mainly present with neurodegenerative features. RAN translation leads to the biosynthesis of low-complexity polymeric repeat proteins with aggregating and cytotoxic properties. However, the molecular mechanisms and protein factors involved in assembling functional ribosomes in absence of canonical AUG start codons remain poorly characterised while secondary repeat RNA structures play key roles in initiating RAN translation. Here, we briefly review the repeat expansion disorders, their complex pathogenesis and the mechanisms of physiological translation initiation together with the known factors involved in RAN translation. Finally, we discuss research challenges surrounding the understanding of pathogenesis and future directions that may provide opportunities for the development of novel therapeutic approaches for this group of incurable neurodegenerative diseases.
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24
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Klingler E, Francis F, Jabaudon D, Cappello S. Mapping the molecular and cellular complexity of cortical malformations. Science 2021; 371:371/6527/eaba4517. [PMID: 33479124 DOI: 10.1126/science.aba4517] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The cerebral cortex is an intricate structure that controls human features such as language and cognition. Cortical functions rely on specialized neurons that emerge during development from complex molecular and cellular interactions. Neurodevelopmental disorders occur when one or several of these steps is incorrectly executed. Although a number of causal genes and disease phenotypes have been identified, the sequence of events linking molecular disruption to clinical expression mostly remains obscure. Here, focusing on human malformations of cortical development, we illustrate how complex interactions at the genetic, cellular, and circuit levels together contribute to diversity and variability in disease phenotypes. Using specific examples and an online resource, we propose that a multilevel assessment of disease processes is key to identifying points of vulnerability and developing new therapeutic strategies.
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Affiliation(s)
- Esther Klingler
- Department of Basic Neurosciences, University of Geneva, CH-1202 Geneva, Switzerland
| | - Fiona Francis
- INSERM U 1270, F-75005 Paris, France.,Sorbonne University, UMR-S 1270, F-75005 Paris, France.,Institut du Fer à Moulin, F-75005 Paris, France
| | - Denis Jabaudon
- Department of Basic Neurosciences, University of Geneva, CH-1202 Geneva, Switzerland. .,Clinic of Neurology, Geneva University Hospital, 1211 Geneva, Switzerland
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25
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International consensus recommendations on the diagnostic work-up for malformations of cortical development. Nat Rev Neurol 2020; 16:618-635. [PMID: 32895508 PMCID: PMC7790753 DOI: 10.1038/s41582-020-0395-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/20/2020] [Indexed: 12/22/2022]
Abstract
Malformations of cortical development (MCDs) are neurodevelopmental disorders that result from abnormal development of the cerebral cortex in utero. MCDs place a substantial burden on affected individuals, their families and societies worldwide, as these individuals can experience lifelong drug-resistant epilepsy, cerebral palsy, feeding difficulties, intellectual disability and other neurological and behavioural anomalies. The diagnostic pathway for MCDs is complex owing to wide variations in presentation and aetiology, thereby hampering timely and adequate management. In this article, the international MCD network Neuro-MIG provides consensus recommendations to aid both expert and non-expert clinicians in the diagnostic work-up of MCDs with the aim of improving patient management worldwide. We reviewed the literature on clinical presentation, aetiology and diagnostic approaches for the main MCD subtypes and collected data on current practices and recommendations from clinicians and diagnostic laboratories within Neuro-MIG. We reached consensus by 42 professionals from 20 countries, using expert discussions and a Delphi consensus process. We present a diagnostic workflow that can be applied to any individual with MCD and a comprehensive list of MCD-related genes with their associated phenotypes. The workflow is designed to maximize the diagnostic yield and increase the number of patients receiving personalized care and counselling on prognosis and recurrence risk.
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26
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Traversa A, Marchionni E, Giovannetti A, Genovesi ML, Panzironi N, Margiotti K, Napoli G, Piceci Sparascio F, De Luca A, Petrizzelli F, Carella M, Cardona F, Bernardo S, Manganaro L, Mazza T, Pizzuti A, Caputo V. Heterozygous nonsense ARX mutation in a family highlights the complexity of clinical and molecular diagnosis in case of chromosomal and single gene disorder co-inheritance. Mol Genet Genomic Med 2020; 8:e1336. [PMID: 32519823 PMCID: PMC7434725 DOI: 10.1002/mgg3.1336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 05/08/2020] [Accepted: 05/12/2020] [Indexed: 11/17/2022] Open
Abstract
Background Corpus callosum agenesis (ACC) is one of the most frequent Central Nervous System (CNS) malformations. However, genetics underlying isolated forms is still poorly recognized. Here, we report on two female familial cases with partial ACC. The proband shows isolated partial ACC and a mild neurodevelopmental phenotype. A fetus from a previous interrupted pregnancy exhibited a complex phenotype including partial ACC and the occurrence of a de novo 17q12 microduplication, which was interpreted as probably disease‐causing. Methods A trio‐based clinical exome sequencing (CES) was performed. Results Clinical exome sequencing data analysis led to identifying a heterozygous nonsense variant (NM_139058.3:c.922G>T; NP_620689.1:p.Glu308Ter) in the aristaless related homeobox gene (ARX) in the proband, with a putative de novo occurrence, producing a hypothetical protein lacking two essential domains. Sanger analysis confirmed the wild‐type status of both parents in different tissues, and disclosed the occurrence of the nonsense variant in the fetus of the interrupted pregnancy, suggesting a formerly unrecognized contribution of the ARX mutation to the fetus' phenotype and gonadal or gonadosomatic mosaicism in one of the parents. Conclusion This study describes the phenotype associated with a heterozygous loss of function variant in ARX. Moreover, it highlights the importance of investigating both chromosomal and genetic contributions in cases of complex syndromic phenotypes involving CNS.
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Affiliation(s)
- Alice Traversa
- Laboratory of Clinical Genomics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo (FG), Italy
| | - Enrica Marchionni
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Agnese Giovannetti
- Laboratory of Clinical Genomics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo (FG), Italy
| | - Maria L Genovesi
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Noemi Panzironi
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | | | - Giulia Napoli
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Francesca Piceci Sparascio
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy.,UOS Diagnosi Genetica Molecolare, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo (FG), Italy
| | - Alessandro De Luca
- UOS Diagnosi Genetica Molecolare, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo (FG), Italy
| | - Francesco Petrizzelli
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy.,Laboratory of Bioinformatics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo (FG), Italy
| | - Massimo Carella
- Laboratory of Medical Genetics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo (FG), Italy
| | - Francesco Cardona
- Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy
| | - Silvia Bernardo
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy.,Department of Radiological, Oncological, and Pathological Anatomy Sciences, Sapienza University of Rome, Rome, Italy
| | - Lucia Manganaro
- Department of Radiological, Oncological, and Pathological Anatomy Sciences, Sapienza University of Rome, Rome, Italy
| | - Tommaso Mazza
- Laboratory of Bioinformatics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo (FG), Italy
| | - Antonio Pizzuti
- Laboratory of Clinical Genomics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo (FG), Italy.,Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - Viviana Caputo
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
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27
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Thai MHN, Gardner A, Redpath L, Mattiske T, Dearsley O, Shaw M, Vulto-van Silfhout AT, Pfundt R, Dixon J, McGaughran J, Pérez-Jurado LA, Gécz J, Shoubridge C. Constraint and conservation of paired-type homeodomains predicts the clinical outcome of missense variants of uncertain significance. Hum Mutat 2020; 41:1407-1424. [PMID: 32383243 DOI: 10.1002/humu.24034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 02/26/2020] [Accepted: 05/03/2020] [Indexed: 12/30/2022]
Abstract
The need to interpret the pathogenicity of novel missense variants of unknown significance identified in the homeodomain of X-chromosome aristaless-related homeobox (ARX) gene prompted us to assess the utility of conservation and constraint across these domains in multiple genes compared to conventional in vitro functional analysis. Pathogenic missense variants clustered in the homeodomain of ARX contribute to intellectual disability (ID) and epilepsy, with and without brain malformation in affected males. Here we report novel c.1112G>A, p.Arg371Gln and c.1150C>T, p.Arg384Cys variants in male patients with ID and severe seizures. The third case of a male patient with a c.1109C>T, p.Ala370Val variant is perhaps the first example of ID and autism spectrum disorder (ASD), without seizures or brain malformation. We compiled data sets of pathogenic variants from ClinVar and presumed benign variation from gnomAD and demonstrated that the high levels of sequence conservation and constraint of benign variation within the homeodomain impacts upon the ability of publicly available in silico prediction tools to accurately discern likely benign from likely pathogenic variants in these data sets. Despite this, considering the inheritance patterns of the genes and disease variants with the conservation and constraint of disease variants affecting the homeodomain in conjunction with current clinical assessments may assist in predicting the pathogenicity of missense variants, particularly for genes with autosomal recessive and X-linked patterns of disease inheritance, such as ARX. In vitro functional analysis demonstrates that the transcriptional activity of all three variants was diminished compared to ARX-Wt. We review the associated phenotypes of the published cases of patients with ARX homeodomain variants and propose expansion of the ARX-related phenotype to include severe ID and ASD without brain malformations or seizures. We propose that the use of the constraint and conservation data in conjunction with consideration of the patient phenotype and inheritance pattern may negate the need for the experimental functional validation currently required to achieve a diagnosis.
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Affiliation(s)
- Monica H N Thai
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia.,Robinson Research Institute, University of Adelaide, Adelaide, South Australia, Australia
| | - Alison Gardner
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
| | - Laura Redpath
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia.,Robinson Research Institute, University of Adelaide, Adelaide, South Australia, Australia
| | - Tessa Mattiske
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia.,Robinson Research Institute, University of Adelaide, Adelaide, South Australia, Australia
| | - Oliver Dearsley
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
| | - Marie Shaw
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia
| | | | - Rolph Pfundt
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joanne Dixon
- Genetic Health Service NZ-South Island Hub, Christchurch Hospital, Christchurch, New Zealand
| | - Julie McGaughran
- Genetic Health Queensland, MNHHS, Brisbane and School of Medicine, The University of Queensland, Brisbane, Queensland, Australia
| | - Luis A Pérez-Jurado
- Robinson Research Institute, University of Adelaide, Adelaide, South Australia, Australia.,South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia.,South Australian Clinical Genetics Service, SA Pathology, Adelaide, South Australia, Australia.,Hospital del Mar Research Institute, Network Research Centre for Rare Diseases and Universitat Pompeu Fabra, Barcelona, Spain
| | - Jozef Gécz
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia.,Robinson Research Institute, University of Adelaide, Adelaide, South Australia, Australia.,South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
| | - Cheryl Shoubridge
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia.,Robinson Research Institute, University of Adelaide, Adelaide, South Australia, Australia
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28
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Takeshita Y, Ohto T, Enokizono T, Tanaka M, Suzuki H, Fukushima H, Uehara T, Takenouchi T, Kosaki K, Takada H. Novel ARX mutation identified in infantile spasm syndrome patient. Hum Genome Var 2020; 7:9. [PMID: 32257294 PMCID: PMC7109071 DOI: 10.1038/s41439-020-0094-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 02/25/2020] [Accepted: 02/26/2020] [Indexed: 11/08/2022] Open
Abstract
We report a 7-year-old boy with infantile spasms caused by a novel mutation in the Aristaless-related homeobox (ARX) gene. He showed infantile spasms and hypsarrhythmia on electroencephalogram from early infancy. Brain MRI did not reveal severe malformation of the brain except mild hypoplasia of the corpus callosum. Two-fold adrenocorticotropic hormone (ACTH) therapy failed to control the seizures, and ketogenic diet therapy and multi-antiepileptic drug therapy were required as he showed intractable daily tonic-clonic seizures. Exome sequencing identified a hemizygous mutation in the ARX gene, NG_008281.1(ARX_v001):c.1448 + 1 G > A, chrX: 25025227 C > T (GRCh37). To our knowledge, this mutation has not been reported previously.
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Affiliation(s)
- Yohei Takeshita
- Department of Pediatrics, Ibaraki Seinan Medical Center Hospital, Sakai-machi, Japan
| | - Tatsuyuki Ohto
- Department of Pediatrics, University of Tsukuba Hospital, Tsukuba, Japan
- Department of Child Health, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Takashi Enokizono
- Department of Pediatrics, University of Tsukuba Hospital, Tsukuba, Japan
| | - Mai Tanaka
- Department of Pediatrics, University of Tsukuba Hospital, Tsukuba, Japan
| | - Hisato Suzuki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Hiroko Fukushima
- Department of Pediatrics, University of Tsukuba Hospital, Tsukuba, Japan
- Department of Child Health, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Tomoko Uehara
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Toshiki Takenouchi
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Kenjiro Kosaki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Hidetoshi Takada
- Department of Pediatrics, University of Tsukuba Hospital, Tsukuba, Japan
- Department of Child Health, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
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29
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Siehr MS, Massey CA, Noebels JL. Arx expansion mutation perturbs cortical development by augmenting apoptosis without activating innate immunity in a mouse model of X-linked infantile spasms syndrome. Dis Model Mech 2020; 13:dmm042515. [PMID: 32033960 PMCID: PMC7132796 DOI: 10.1242/dmm.042515] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 01/27/2020] [Indexed: 01/12/2023] Open
Abstract
X-linked infantile spasms syndrome (ISSX) is a clinically devastating developmental epileptic encephalopathy with life-long impact. Arx(GCG)10+7 , a mouse model of the most common triplet-repeat expansion mutation of ARX, exhibits neonatal spasms, electrographic phenotypes and abnormal migration of GABAergic interneuron subtypes. Neonatal presymptomatic treatment with 17β-estradiol (E2) in Arx(GCG)10+7 reduces spasms and modifies progression of epilepsy. Cortical pathology during this period, a crucial point for clinical intervention in ISSX, has largely been unexplored, and the pathogenic cellular defects that are targeted by early interventions are unknown. In the first postnatal week, we identified a transient wave of elevated apoptosis in Arx(GCG)10+7 mouse cortex that is non-Arx cell autonomous, since mutant Arx-immunoreactive (Arx+) cells are not preferentially impacted by cell death. NeuN+ (also known as Rbfox3) survival was also not impacted, suggesting a vulnerable subpopulation in the immature Arx(GCG)10+7 cortex. Inflammatory processes during this period might explain this transient elevation in apoptosis; however, transcriptomic and immunohistochemical profiling of several markers of inflammation revealed no innate immune activation in Arx(GCG)10+7 cortex. Neither neonatal E2 hormone therapy, nor ACTH(1-24), the frontline clinical therapy for ISSX, diminished the augmented apoptosis in Arx(GCG)10+7 , but both rescued neocortical Arx+ cell density. Since early E2 treatment effectively prevents seizures in this model, enhanced apoptosis does not solely account for the seizure phenotype, but may contribute to other aberrant brain function in ISSX. However, since both hormone therapies, E2 and ACTH(1-24), elevate the density of cortical Arx+-interneurons, their early therapeutic role in other neurological disorders hallmarked by interneuronopathy should be explored.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Meagan S Siehr
- Developmental Neurogenetics Laboratory, Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
- Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Cory A Massey
- Developmental Neurogenetics Laboratory, Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Jeffrey L Noebels
- Developmental Neurogenetics Laboratory, Department of Neurology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
- Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
- Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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30
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Subramanian L, Calcagnotto ME, Paredes MF. Cortical Malformations: Lessons in Human Brain Development. Front Cell Neurosci 2020; 13:576. [PMID: 32038172 PMCID: PMC6993122 DOI: 10.3389/fncel.2019.00576] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Accepted: 12/16/2019] [Indexed: 12/11/2022] Open
Abstract
Creating a functional cerebral cortex requires a series of complex and well-coordinated developmental steps. These steps have evolved across species with the emergence of cortical gyrification and coincided with more complex behaviors. The presence of diverse progenitor cells, a protracted timeline for neuronal migration and maturation, and diverse neuronal types are developmental features that have emerged in the gyrated cortex. These factors could explain how the human brain has expanded in size and complexity. However, their complex nature also renders new avenues of vulnerability by providing additional cell types that could contribute to disease and longer time windows that could impact the composition and organization of the cortical circuit. We aim to discuss the unique developmental steps observed in human corticogenesis and propose how disruption of these species-unique processes could lead to malformations of cortical development.
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Affiliation(s)
- Lakshmi Subramanian
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, United States
| | - Maria Elisa Calcagnotto
- Neurophysiology and Neurochemistry of Neuronal Excitability and Synaptic Plasticity Laboratory, Department of Biochemistry, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Graduate Program in Neuroscience, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Mercedes F Paredes
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, United States.,Department of Neurology, University of California, San Francisco, San Francisco, CA, United States.,Neuroscience Graduate Division, University of California, San Francisco, San Francisco, CA, United States
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31
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De Mori R, Severino M, Mancardi MM, Anello D, Tardivo S, Biagini T, Capra V, Casella A, Cereda C, Copeland BR, Gagliardi S, Gamucci A, Ginevrino M, Illi B, Lorefice E, Musaev D, Stanley V, Micalizzi A, Gleeson JG, Mazza T, Rossi A, Valente EM. Agenesis of the putamen and globus pallidus caused by recessive mutations in the homeobox gene GSX2. Brain 2019; 142:2965-2978. [PMID: 31412107 PMCID: PMC6776115 DOI: 10.1093/brain/awz247] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 06/06/2019] [Accepted: 06/18/2019] [Indexed: 12/31/2022] Open
Abstract
Basal ganglia are subcortical grey nuclei that play essential roles in controlling voluntary movements, cognition and emotion. While basal ganglia dysfunction is observed in many neurodegenerative or metabolic disorders, congenital malformations are rare. In particular, dysplastic basal ganglia are part of the malformative spectrum of tubulinopathies and X-linked lissencephaly with abnormal genitalia, but neurodevelopmental syndromes characterized by basal ganglia agenesis are not known to date. We ascertained two unrelated children (both female) presenting with spastic tetraparesis, severe generalized dystonia and intellectual impairment, sharing a unique brain malformation characterized by agenesis of putamina and globi pallidi, dysgenesis of the caudate nuclei, olfactory bulbs hypoplasia, and anomaly of the diencephalic-mesencephalic junction with abnormal corticospinal tract course. Whole-exome sequencing identified two novel homozygous variants, c.26C>A; p.(S9*) and c.752A>G; p.(Q251R) in the GSX2 gene, a member of the family of homeobox transcription factors, which are key regulators of embryonic development. GSX2 is highly expressed in neural progenitors of the lateral and median ganglionic eminences, two protrusions of the ventral telencephalon from which the basal ganglia and olfactory tubercles originate, where it promotes neurogenesis while negatively regulating oligodendrogenesis. The truncating variant resulted in complete loss of protein expression, while the missense variant affected a highly conserved residue of the homeobox domain, was consistently predicted as pathogenic by bioinformatic tools, resulted in reduced protein expression and caused impaired structural stability of the homeobox domain and weaker interaction with DNA according to molecular dynamic simulations. Moreover, the nuclear localization of the mutant protein in transfected cells was significantly reduced compared to the wild-type protein. Expression studies on both patients' fibroblasts demonstrated reduced expression of GSX2 itself, likely due to altered transcriptional self-regulation, as well as significant expression changes of related genes such as ASCL1 and PAX6. Whole transcriptome analysis revealed a global deregulation in genes implicated in apoptosis and immunity, two broad pathways known to be involved in brain development. This is the first report of the clinical phenotype and molecular basis associated to basal ganglia agenesis in humans.
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Affiliation(s)
- Roberta De Mori
- Neurogenetics Unit, IRCCS Santa Lucia Foundation, Rome, Italy
| | | | | | - Danila Anello
- Neurogenetics Unit, IRCCS Santa Lucia Foundation, Rome, Italy
| | - Silvia Tardivo
- Neurogenetics Unit, IRCCS Santa Lucia Foundation, Rome, Italy
| | - Tommaso Biagini
- IRCCS Casa Sollievo della Sofferenza, Laboratory of Bioinformatics, San Giovanni Rotondo (FG), Italy
| | - Valeria Capra
- Neurosurgery Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | | | - Cristina Cereda
- Genomic and Postgenomic Lab, IRCCS Mondino Foundation, Pavia, Italy
| | - Brett R Copeland
- Laboratory for Pediatric Brain Diseases, Rady Children’s Institute for Genomic Medicine, University of California San Diego, Howard Hughes Medical Institute, La Jolla (CA), USA
| | - Stella Gagliardi
- Genomic and Postgenomic Lab, IRCCS Mondino Foundation, Pavia, Italy
| | - Alessandra Gamucci
- Child Neuropsychiatry Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Monia Ginevrino
- Neurogenetics Unit, IRCCS Santa Lucia Foundation, Rome, Italy
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Barbara Illi
- Institute of Molecular Biology and Pathology, National Research Council, Rome, Italy
| | - Elisa Lorefice
- Department of Molecular Medicine, Sapienza University, Rome, Italy
| | - Damir Musaev
- Laboratory for Pediatric Brain Diseases, Rady Children’s Institute for Genomic Medicine, University of California San Diego, Howard Hughes Medical Institute, La Jolla (CA), USA
| | - Valentina Stanley
- Laboratory for Pediatric Brain Diseases, Rady Children’s Institute for Genomic Medicine, University of California San Diego, Howard Hughes Medical Institute, La Jolla (CA), USA
| | - Alessia Micalizzi
- Laboratory of Medical Genetics, Bambino Gesù Children’s Hospital, Rome, Italy
| | - Joseph G Gleeson
- Laboratory for Pediatric Brain Diseases, Rady Children’s Institute for Genomic Medicine, University of California San Diego, Howard Hughes Medical Institute, La Jolla (CA), USA
| | - Tommaso Mazza
- IRCCS Casa Sollievo della Sofferenza, Laboratory of Bioinformatics, San Giovanni Rotondo (FG), Italy
| | - Andrea Rossi
- Neuroradiology Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Enza Maria Valente
- Neurogenetics Unit, IRCCS Santa Lucia Foundation, Rome, Italy
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
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32
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Sznajder ŁJ, Swanson MS. Short Tandem Repeat Expansions and RNA-Mediated Pathogenesis in Myotonic Dystrophy. Int J Mol Sci 2019; 20:ijms20133365. [PMID: 31323950 PMCID: PMC6651174 DOI: 10.3390/ijms20133365] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 06/27/2019] [Accepted: 07/08/2019] [Indexed: 12/23/2022] Open
Abstract
Short tandem repeat (STR) or microsatellite, expansions underlie more than 50 hereditary neurological, neuromuscular and other diseases, including myotonic dystrophy types 1 (DM1) and 2 (DM2). Current disease models for DM1 and DM2 propose a common pathomechanism, whereby the transcription of mutant DMPK (DM1) and CNBP (DM2) genes results in the synthesis of CUG and CCUG repeat expansion (CUGexp, CCUGexp) RNAs, respectively. These CUGexp and CCUGexp RNAs are toxic since they promote the assembly of ribonucleoprotein (RNP) complexes or RNA foci, leading to sequestration of Muscleblind-like (MBNL) proteins in the nucleus and global dysregulation of the processing, localization and stability of MBNL target RNAs. STR expansion RNAs also form phase-separated gel-like droplets both in vitro and in transiently transfected cells, implicating RNA-RNA multivalent interactions as drivers of RNA foci formation. Importantly, the nucleation and growth of these nuclear foci and transcript misprocessing are reversible processes and thus amenable to therapeutic intervention. In this review, we provide an overview of potential DM1 and DM2 pathomechanisms, followed by a discussion of MBNL functions in RNA processing and how multivalent interactions between expanded STR RNAs and RNA-binding proteins (RBPs) promote RNA foci assembly.
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Affiliation(s)
- Łukasz J Sznajder
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL 32610, USA.
| | - Maurice S Swanson
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL 32610, USA
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33
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Shoubridge C, Jackson M, Grinton B, Berkovic SF, Scheffer IE, Huskins S, Thomas A, Ware T. Splice variant in ARX leading to loss of C-terminal region in a boy with intellectual disability and infantile onset developmental and epileptic encephalopathy. Am J Med Genet A 2019; 179:1483-1490. [PMID: 31145546 DOI: 10.1002/ajmg.a.61216] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 03/07/2019] [Accepted: 05/05/2019] [Indexed: 02/06/2023]
Abstract
Pathogenic variants in the X-chromosome Aristaless-related homeobox (ARX) gene contribute to intellectual disability, epilepsy, and associated comorbidities in affected males. Here, we report a novel splice variant in ARX in a family with three affected individuals. The proband had early onset developmental and epileptic encephalopathy, his brother and mother had severe and mild intellectual disability, respectively. Massively parallel sequencing identified a novel c.1449-1G>C in intron 4 of the ARX gene, predicted to abolish the splice acceptor site, retaining intron 4 and leading to a premature termination codon immediately after exon 4. As exon 5 is the last exon of the ARX gene, the premature termination codon at position p.L484* would be predicted to escape nonsense-mediated mRNA decay, potentially producing at least some C-terminally truncated protein. Analysis of cDNA from patient lymphoblastoid cells confirmed retention of intron 4 and loss of detectable expression of ARX mRNA across exon 4 to exon 5. We review published cases of variants that lead to altered or early termination of the ARX protein, but not complete loss of function, and are associated with phenotypes of intellectual disability and infantile onset developmental and epileptic encephalopathies, including Ohtahara and West syndromes. Taken together, this novel splice variant retaining intron 4 is likely to be the cause of the early onset developmental and epileptic encephalopathy in the proband.
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Affiliation(s)
- Cheryl Shoubridge
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia.,Robinson Research Institute, University of Adelaide, Adelaide, South Australia, Australia
| | - Matilda Jackson
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia, Australia.,Robinson Research Institute, University of Adelaide, Adelaide, South Australia, Australia
| | - Bronwyn Grinton
- Department of Medicine, University of Melbourne, Austin Health, Melbourne, Victoria, Australia
| | - Samuel F Berkovic
- Department of Medicine, University of Melbourne, Austin Health, Melbourne, Victoria, Australia
| | - Ingrid E Scheffer
- Department of Medicine, University of Melbourne, Austin Health, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Florey and Murdoch Children's Research Institutes, Melbourne, Victoria, Australia
| | - Shannon Huskins
- Department of Medicine, University of Tasmania, Hobart, Tasmania, Australia
| | - Alison Thomas
- Department of Medical Imaging, Royal Hobart Hospital, Hobart, Tasmania, Australia
| | - Tyson Ware
- Department of Paediatrics, Royal Hobart Hospital, Hobart, Tasmania, Australia
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34
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Represa A. Why Malformations of Cortical Development Cause Epilepsy. Front Neurosci 2019; 13:250. [PMID: 30983952 PMCID: PMC6450262 DOI: 10.3389/fnins.2019.00250] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 03/04/2019] [Indexed: 12/13/2022] Open
Abstract
Malformations of cortical development (MCDs), a complex family of rare disorders, result from alterations of one or combined developmental steps, including progenitors proliferation, neuronal migration and differentiation. They are an important cause of childhood epilepsy and frequently associate cognitive deficits and behavioral alterations. Though the physiopathological mechanisms of epilepsy in MCD patients remain poorly elucidated, research during the past decade highlighted the contribution of some factors that will be reviewed in this paper and that include: (i) the genes that caused the malformation, that can be responsible for a significant reduction of inhibitory cells (e.g., ARX gene) or be inducing cell-autonomous epileptogenic changes in affected neurons (e.g., mutations on the mTOR pathway); (ii) the alteration of cortical networks development induced by the malformation that will also involve adjacent or distal cortical areas apparently sane so that the epileptogenic focus might be more extended that the malformation or even localized at distance from it; (iii) the normal developmental processes that would influence and determine the onset of epilepsy in MCD patients, particularly precocious in most of the cases.
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Affiliation(s)
- Alfonso Represa
- INSERM, Institut de Neurobiologie de la Méditerranée, Aix-Marseille University, Marseille, France
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35
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Parivesh A, Barseghyan H, Délot E, Vilain E. Translating genomics to the clinical diagnosis of disorders/differences of sex development. Curr Top Dev Biol 2019; 134:317-375. [PMID: 30999980 PMCID: PMC7382024 DOI: 10.1016/bs.ctdb.2019.01.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The medical and psychosocial challenges faced by patients living with Disorders/Differences of Sex Development (DSD) and their families can be alleviated by a rapid and accurate diagnostic process. Clinical diagnosis of DSD is limited by a lack of standardization of anatomical and endocrine phenotyping and genetic testing, as well as poor genotype/phenotype correlation. Historically, DSD genes have been identified through positional cloning of disease-associated variants segregating in families and validation of candidates in animal and in vitro modeling of variant pathogenicity. Owing to the complexity of conditions grouped under DSD, genome-wide scanning methods are better suited for identifying disease causing gene variant(s) and providing a clinical diagnosis. Here, we review a number of established genomic tools (karyotyping, chromosomal microarrays and exome sequencing) used in clinic for DSD diagnosis, as well as emerging genomic technologies such as whole-genome (short-read) sequencing, long-read sequencing, and optical mapping used for novel DSD gene discovery. These, together with gene expression and epigenetic studies can potentiate the clinical diagnosis of DSD diagnostic rates and enhance the outcomes for patients and families.
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Affiliation(s)
- Abhinav Parivesh
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC, United States
| | - Hayk Barseghyan
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC, United States; Department of Genomics and Precision Medicine, The George Washington University, Washington, DC, United States
| | - Emmanuèle Délot
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC, United States; Department of Genomics and Precision Medicine, The George Washington University, Washington, DC, United States.
| | - Eric Vilain
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC, United States; Department of Genomics and Precision Medicine, The George Washington University, Washington, DC, United States.
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36
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Dubos A, Meziane H, Iacono G, Curie A, Riet F, Martin C, Loaëc N, Birling MC, Selloum M, Normand E, Pavlovic G, Sorg T, Stunnenberg HG, Chelly J, Humeau Y, Friocourt G, Hérault Y. A new mouse model of ARX dup24 recapitulates the patients' behavioral and fine motor alterations. Hum Mol Genet 2019; 27:2138-2153. [PMID: 29659809 PMCID: PMC5985730 DOI: 10.1093/hmg/ddy122] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Accepted: 03/26/2018] [Indexed: 01/27/2023] Open
Abstract
The aristaless-related homeobox (ARX) transcription factor is involved in the development of GABAergic and cholinergic neurons in the forebrain. ARX mutations have been associated with a wide spectrum of neurodevelopmental disorders in humans, among which the most frequent, a 24 bp duplication in the polyalanine tract 2 (c.428_451dup24), gives rise to intellectual disability, fine motor defects with or without epilepsy. To understand the functional consequences of this mutation, we generated a partially humanized mouse model carrying the c.428_451dup24 duplication (Arxdup24/0) that we characterized at the behavior, neurological and molecular level. Arxdup24/0 males presented with hyperactivity, enhanced stereotypies and altered contextual fear memory. In addition, Arxdup24/0 males had fine motor defects with alteration of reaching and grasping abilities. Transcriptome analysis of Arxdup24/0 forebrains at E15.5 showed a down-regulation of genes specific to interneurons and an up-regulation of genes normally not expressed in this cell type, suggesting abnormal interneuron development. Accordingly, interneuron migration was altered in the cortex and striatum between E15.5 and P0 with consequences in adults, illustrated by the defect in the inhibitory/excitatory balance in Arxdup24/0 basolateral amygdala. Altogether, we showed that the c.428_451dup24 mutation disrupts Arx function with a direct consequence on interneuron development, leading to hyperactivity and defects in precise motor movement control and associative memory. Interestingly, we highlighted striking similarities between the mouse phenotype and a cohort of 33 male patients with ARX c.428_451dup24, suggesting that this new mutant mouse line is a good model for understanding the pathophysiology and evaluation of treatment.
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Affiliation(s)
- Aline Dubos
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Université de Strasbourg, 67404 Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, 67404 Illkirch, France.,CELPHEDIA, PHENOMIN, Institut Clinique de la Souris, 67404 Illkirch, France
| | - Hamid Meziane
- CELPHEDIA, PHENOMIN, Institut Clinique de la Souris, 67404 Illkirch, France
| | - Giovanni Iacono
- Department of Molecular Biology, Radboud Institute for Molecular Life Sciences, Radboud University, 6500 HB Nijmegen, The Netherlands
| | - Aurore Curie
- Centre de Référence Déficiences Intellectuelles de Causes Rares, Hôpital Femmes Mères Enfants, Hospices Civils de Lyon, Institut des Sciences Cognitives, CNRS UMR5304, Université Claude Bernard Lyon1, 69675 Bron, France
| | - Fabrice Riet
- CELPHEDIA, PHENOMIN, Institut Clinique de la Souris, 67404 Illkirch, France
| | - Christelle Martin
- Team Synapse in Cognition, Institut Interdisciplinaire de NeuroScience, Centre National de la Recherche Scientifique CNRS UMR5297, Université de Bordeaux, 33077 Bordeaux, France
| | - Nadège Loaëc
- Inserm UMR 1078, Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé, Etablissement Français du Sang (EFS) Bretagne, CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, 29200 Brest, France
| | | | - Mohammed Selloum
- CELPHEDIA, PHENOMIN, Institut Clinique de la Souris, 67404 Illkirch, France
| | - Elisabeth Normand
- Team Synapse in Cognition, Institut Interdisciplinaire de NeuroScience, Centre National de la Recherche Scientifique CNRS UMR5297, Université de Bordeaux, 33077 Bordeaux, France.,Pole In Vivo, Institut Interdisciplinaire de NeuroScience, Centre National de la Recherche Scientifique CNRS UMR5297, Université de Bordeaux, 33077 Bordeaux, France
| | - Guillaume Pavlovic
- CELPHEDIA, PHENOMIN, Institut Clinique de la Souris, 67404 Illkirch, France
| | - Tania Sorg
- CELPHEDIA, PHENOMIN, Institut Clinique de la Souris, 67404 Illkirch, France
| | - Henk G Stunnenberg
- Department of Molecular Biology, Radboud Institute for Molecular Life Sciences, Radboud University, 6500 HB Nijmegen, The Netherlands
| | - Jamel Chelly
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Université de Strasbourg, 67404 Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, 67404 Illkirch, France.,Service de Diagnostic Génétique, Hôpital Civil de Strasbourg, Hôpitaux Universitaires de Strasbourg, 67091 Strasbourg, France
| | - Yann Humeau
- Team Synapse in Cognition, Institut Interdisciplinaire de NeuroScience, Centre National de la Recherche Scientifique CNRS UMR5297, Université de Bordeaux, 33077 Bordeaux, France
| | - Gaëlle Friocourt
- Inserm UMR 1078, Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé, Etablissement Français du Sang (EFS) Bretagne, CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, 29200 Brest, France
| | - Yann Hérault
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Université de Strasbourg, 67404 Illkirch, France.,Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France.,Institut National de la Santé et de la Recherche Médicale, U1258, 67404 Illkirch, France.,CELPHEDIA, PHENOMIN, Institut Clinique de la Souris, 67404 Illkirch, France
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37
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Lim Y, Cho IT, Shi X, Grinspan JB, Cho G, Golden JA. Arx Expression Suppresses Ventralization of the Developing Dorsal Forebrain. Sci Rep 2019; 9:226. [PMID: 30659230 PMCID: PMC6338776 DOI: 10.1038/s41598-018-36194-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 11/11/2018] [Indexed: 12/22/2022] Open
Abstract
Early brain development requires a tight orchestration between neural tube patterning and growth. How pattern formation and brain growth are coordinated is incompletely understood. Previously we showed that aristaless-related homeobox (ARX), a paired-like transcription factor, regulates cortical progenitor pool expansion by repressing an inhibitor of cell cycle progression. Here we show that ARX participates in establishing dorsoventral identity in the mouse forebrain. In Arx mutant mice, ventral genes, including Olig2, are ectopically expressed dorsally. Furthermore, Gli1 is upregulated, suggesting an ectopic activation of SHH signaling. We show that the ectopic Olig2 expression can be repressed by blocking SHH signaling, implicating a role for SHH signaling in Olig2 induction. We further demonstrate that the ectopic Olig2 accounts for the reduced Pax6 and Tbr2 expression, both dorsal specific genes essential for cortical progenitor cell proliferation. These data suggest a link between the control of dorsoventral identity of progenitor cells and the control of their proliferation. In summary, our data demonstrate that ARX functions in a gene regulatory network integrating normal forebrain patterning and growth, providing important insight into how mutations in ARX can disrupt multiple aspects of brain development and thus generate a wide spectrum of neurodevelopmental phenotypes observed in human patients.
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Affiliation(s)
- Youngshin Lim
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Il-Taeg Cho
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Xiuyu Shi
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA.,School of Life Sciences, Xiamen University, Xiamen, Fujian, 361005, China
| | - Judith B Grinspan
- Department of Neurology, Children's Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Ginam Cho
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
| | - Jeffrey A Golden
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
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38
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Buchsbaum IY, Cappello S. Neuronal migration in the CNS during development and disease: insights from in vivo and in vitro models. Development 2019; 146:146/1/dev163766. [DOI: 10.1242/dev.163766] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
ABSTRACT
Neuronal migration is a fundamental process that governs embryonic brain development. As such, mutations that affect essential neuronal migration processes lead to severe brain malformations, which can cause complex and heterogeneous developmental and neuronal migration disorders. Our fragmented knowledge about the aetiology of these disorders raises numerous issues. However, many of these can now be addressed through studies of in vivo and in vitro models that attempt to recapitulate human-specific mechanisms of cortical development. In this Review, we discuss the advantages and limitations of these model systems and suggest that a complementary approach, using combinations of in vivo and in vitro models, will broaden our knowledge of the molecular and cellular mechanisms that underlie defective neuronal positioning in the human cerebral cortex.
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Affiliation(s)
- Isabel Yasmin Buchsbaum
- Developmental Neurobiology, Max Planck Institute of Psychiatry, 80804 Munich, Germany
- Graduate School of Systemic Neurosciences, Ludwig-Maximilians-University Munich, 82152 Planegg, Germany
| | - Silvia Cappello
- Developmental Neurobiology, Max Planck Institute of Psychiatry, 80804 Munich, Germany
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39
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Abstract
Disorders of the developing nervous system may be of genetic origin, comprising congenital malformations of spine and brain as well as metabolic or vascular disorders that affect normal brain development. Acquired causes include congenital infections, hypoxic-ischemic or traumatic brain injury, and a number of rare neoplasms. This chapter focuses on the clinical presentation and workup of neurogenetic disorders presenting in the fetal or neonatal period. After a summary of the most frequent clinical presentations, clues from history taking and clinical examination are illustrated with short case reports. This is followed by a discussion of the different tools available for the workup of neurogenetic disorders, including the various genetic techniques with their advantages and disadvantages. The implications of a molecular genetic diagnosis for the patient and family are addressed in the section on counseling. The chapter concludes with a proposed workflow that may help the clinician when confronted with a potential neurogenetic disorder in the fetal or neonatal period.
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40
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Wu Y, Zhang H, Liu X, Shi Z, Li H, Wang Z, Jie X, Huang S, Zhang F, Li J, Zhang K, Gao X. Mutations of ARX and non-syndromic intellectual disability in Chinese population. Genes Genomics 2018; 41:125-131. [PMID: 30255221 DOI: 10.1007/s13258-018-0745-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 09/15/2018] [Indexed: 02/08/2023]
Abstract
Mutations of Aristaless-related homeobox (ARX) gene were looked as the third cause of non-syndromic intellectual disability (NSID), while the boundary between true disease-causing mutations and non-disease-causing variants within this gene remains elusive. To investigate the relationship between ARX mutations and NSID, a panel comprising six reported causal mutations of the ARX was detected in 369 sporadic NSID patients and 550 random participants in Chinese. Two mutations, c.428_451 dup and p.G286S, may be disease-causing mutations for NSID, while p.Q163R and p.P353L showed a great predictive value in female NSID diagnosis with significant associations (X2 = 19.60, p = 9.54e-6 for p.Q163R; X2 = 25.70, p = 4.00e-07 for p.P353L), carriers of these mutations had an increased risk of NSID of more than fourfold. Detection of this panel also predicted significant associations between genetic variants of the ARX gene and NSID (p = 3.73e-4). The present study emphasized the higher genetic burden of the ARX gene on NSID in the Chinese population, molecular analysis of this gene should be considered for patients presenting NSID of unknown etiology.
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Affiliation(s)
- Yufei Wu
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, Northwest University, Xi'an, 710069, China
| | - Huan Zhang
- The 2nd Affiliated Hospital, Xi'an Jiaotong University, Xi'an, 710004, China
| | - Xiaofen Liu
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, Northwest University, Xi'an, 710069, China
| | - Zhangyan Shi
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, Northwest University, Xi'an, 710069, China
| | - Hongling Li
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, Northwest University, Xi'an, 710069, China
| | - Zhibin Wang
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, Northwest University, Xi'an, 710069, China
| | - Xiaoyong Jie
- Xi'an Cangning Psychiatric Hospital, Xi'an, 710114, China
| | - Shaoping Huang
- The 2nd Affiliated Hospital, Xi'an Jiaotong University, Xi'an, 710004, China
| | - Fuchang Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, Northwest University, Xi'an, 710069, China.,College of Public Management, Institute of Application Psychology, Northwest University, Xi'an, 710127, China
| | - Junlin Li
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, Northwest University, Xi'an, 710069, China
| | - Kejin Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, Northwest University, Xi'an, 710069, China.
| | - Xiaocai Gao
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Population and Health, Northwest University, Xi'an, 710069, China. .,College of Public Management, Institute of Application Psychology, Northwest University, Xi'an, 710127, China.
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41
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Abstract
PURPOSE OF REVIEW The current review focuses on the neonatal presentation of disorders of sex development, summarize the current approach to the evaluation of newborns and describes recent advances in understanding of underlying genetic aetiology of these conditions. RECENT FINDINGS Several possible candidate genes as well as other adverse environmental factors have been described as contributing to several clinical subgroups of 46,XY DSDs. Moreover, registry-based studies showed that infants with suspected DSD may have extragenital anomalies and in 46,XY cases, being small for gestational age (SGA), cardiac and neurological malformations are the commonest concomitant conditions. SUMMARY Considering that children and adults with DSD may be at risk of several comorbidities a clear aetiological diagnosis will guide further management. To date, a firm diagnosis is not reached in over half of the cases of 46,XY DSD. Whilst it is likely that improved diagnostic resources will bridge this gap in the future, the next challenge to the clinical community will be to show that such advances will result in an improvement in clinical care.
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42
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Genetics and mechanisms leading to human cortical malformations. Semin Cell Dev Biol 2018; 76:33-75. [DOI: 10.1016/j.semcdb.2017.09.031] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 09/21/2017] [Accepted: 09/21/2017] [Indexed: 02/06/2023]
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43
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Abstract
X-linked cerebellar ataxias (XLCA) are an expanding group of genetically heterogeneous and clinically variable conditions characterized by cerebellar dysgenesis (hypoplasia, atrophy, or dysplasia) caused by gene mutations or genomic imbalances on the X chromosome. The neurologic features of XLCA include hypotonia, developmental delay, intellectual disability, ataxia, and other cerebellar signs. Normal cognitive development has also been reported. Cerebellar defects may be isolated or associated with other brain malformations or extraneurologic involvement. More than 20 genes on the X chromosome, mainly encoding for proteins involved in brain development and synaptic function that have been constantly or occasionally associated with a pathologic cerebellar phenotype, and several families with X-linked inheritance have been reported. Given the excess of males with ataxia, this group of conditions is probably underestimated and families of patients with neuroradiologic and clinical evidence of a cerebellar disorder should be counseled for high risk of X-linked inheritance.
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Affiliation(s)
- Ginevra Zanni
- Unit of Neuromuscular and Neurodegenerative Disorders, Bambino Gesu' Children's Research Hospital, Rome, Italy.
| | - Enrico Bertini
- Unit of Neuromuscular and Neurodegenerative Disorders, Bambino Gesu' Children's Research Hospital, Rome, Italy
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44
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Intrinsic Disorder in Proteins with Pathogenic Repeat Expansions. Molecules 2017; 22:molecules22122027. [PMID: 29186753 PMCID: PMC6149999 DOI: 10.3390/molecules22122027] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 11/18/2017] [Accepted: 11/21/2017] [Indexed: 11/18/2022] Open
Abstract
Intrinsically disordered proteins and proteins with intrinsically disordered regions have been shown to be highly prevalent in disease. Furthermore, disease-causing expansions of the regions containing tandem amino acid repeats often push repetitive proteins towards formation of irreversible aggregates. In fact, in disease-relevant proteins, the increased repeat length often positively correlates with the increased aggregation efficiency and the increased disease severity and penetrance, being negatively correlated with the age of disease onset. The major categories of repeat extensions involved in disease include poly-glutamine and poly-alanine homorepeats, which are often times located in the intrinsically disordered regions, as well as repeats in non-coding regions of genes typically encoding proteins with ordered structures. Repeats in such non-coding regions of genes can be expressed at the mRNA level. Although they can affect the expression levels of encoded proteins, they are not translated as parts of an affected protein and have no effect on its structure. However, in some cases, the repetitive mRNAs can be translated in a non-canonical manner, generating highly repetitive peptides of different length and amino acid composition. The repeat extension-caused aggregation of a repetitive protein may represent a pivotal step for its transformation into a proteotoxic entity that can lead to pathology. The goals of this article are to systematically analyze molecular mechanisms of the proteinopathies caused by the poly-glutamine and poly-alanine homorepeat expansion, as well as by the polypeptides generated as a result of the microsatellite expansions in non-coding gene regions and to examine the related proteins. We also present results of the analysis of the prevalence and functional roles of intrinsic disorder in proteins associated with pathological repeat expansions.
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45
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Coman D, Fullston T, Shoubridge C, Leventer R, Wong F, Nazaretian S, Simpson I, Gecz J, McGillivray G. X-Linked Lissencephaly With Absent Corpus Callosum and Abnormal Genitalia: An Evolving Multisystem Syndrome With Severe Congenital Intestinal Diarrhea Disease. Child Neurol Open 2017; 4:2329048X17738625. [PMID: 29152528 PMCID: PMC5680935 DOI: 10.1177/2329048x17738625] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 09/06/2017] [Accepted: 09/20/2017] [Indexed: 11/16/2022] Open
Abstract
X-linked lissencephaly with abnormal genitalia is a rare and devastating syndrome. The authors present an infant with a multisystem phenotype where the intestinal manifestations were as life limiting as the central nervous system features. Severe chronic diarrhea resulted in failure to thrive, dehydration, electrolyte derangements, long-term hospitalization, and prompted transition to palliative care. Other multisystem manifestations included megacolon, colitis, pancreatic insufficiency hypothalamic dysfunction, hypothyroidism, and hypophosphatasia. A novel aristaless-related homeobox gene mutation, c.1136G>T/p.R379L, was identified. This case contributes to the clinical, histological, and molecular understanding of the multisystem nature of this disorder, especially the role of ARX in the development of the enteroendocrine system.
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Affiliation(s)
- David Coman
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia.,School of Medicine, The University of Queensland, Brisbane, Queensland, Australia.,School of Medicine, Griffith University, Gold Coast, Queensland, Australia
| | - Tom Fullston
- Department of Genetic Medicine, Women's and Children's Hospital, North Adelaide, South Australia, Australia.,School of Paediatrics and Reproductive Health, University of Adelaide, Adelaide, South Australia, Australia
| | - Cheryl Shoubridge
- Department of Genetic Medicine, Women's and Children's Hospital, North Adelaide, South Australia, Australia
| | - Richard Leventer
- Department of Neurology, Royal Children's Hospital, Melbourne, Victoria, Australia.,Murdoch Children's Research Institute, Melbourne, Victoria, Australia.,Department of Pediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Flora Wong
- Department of Newborn Services, Monash Medical Centre, Melbourne, Victoria, Australia
| | - Simon Nazaretian
- Department of Anatomical Pathology, Monash Medical Centre, Melbourne, Victoria, Australia
| | - Ian Simpson
- Department of Anatomical Pathology, Monash Medical Centre, Melbourne, Victoria, Australia
| | - Josef Gecz
- Department of Genetic Medicine, Women's and Children's Hospital, North Adelaide, South Australia, Australia.,School of Paediatrics and Reproductive Health, University of Adelaide, Adelaide, South Australia, Australia
| | - George McGillivray
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia
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46
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Katsarou A, Moshé SL, Galanopoulou AS. INTERNEURONOPATHIES AND THEIR ROLE IN EARLY LIFE EPILEPSIES AND NEURODEVELOPMENTAL DISORDERS. Epilepsia Open 2017; 2:284-306. [PMID: 29062978 PMCID: PMC5650248 DOI: 10.1002/epi4.12062] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/03/2017] [Indexed: 12/22/2022] Open
Abstract
GABAergic interneurons control the neural circuitry and network activity in the brain. The advances in genetics have identified genes that control the development, maturation and integration of GABAergic interneurons and implicated them in the pathogenesis of epileptic encephalopathies or neurodevelopmental disorders. For example, mutations of the Aristaless-Related homeobox X-linked gene (ARX) may result in defective GABAergic interneuronal migration in infants with epileptic encephalopathies like West syndrome (WS), Ohtahara syndrome or X-linked lissencephaly with abnormal genitalia (XLAG). The concept of "interneuronopathy", i.e. impaired development, migration or function of interneurons, has emerged as a possible etiopathogenic mechanism for epileptic encephalopathies. Treatments that enhance GABA levels, may help seizure control but do not necessarily show disease modifying effect. On the other hand, interneuronopathies can be seen in other conditions in which epilepsy may not be the primary manifestation, such as autism. In this review, we plan to outline briefly the current state of knowledge on the origin, development, and migration and integration of GABAergic interneurons, present neurodevelopmental conditions, with or without epilepsy, that have been associated with interneuronopathies and discuss the evidence linking certain types of interneuronal dysfunction with epilepsy and/or cognitive or behavioral deficits.
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Affiliation(s)
- Anna‐Maria Katsarou
- Laboratory of Developmental EpilepsySaul R. Korey Department of NeurologyAlbert Einstein College of MedicineBronxNew YorkU.S.A.
| | - Solomon L. Moshé
- Laboratory of Developmental EpilepsySaul R. Korey Department of NeurologyAlbert Einstein College of MedicineBronxNew YorkU.S.A.
- Dominick P. Purpura Department of NeuroscienceMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
- Department of PediatricsAlbert Einstein College of MedicineBronxNew YorkU.S.A.
| | - Aristea S. Galanopoulou
- Laboratory of Developmental EpilepsySaul R. Korey Department of NeurologyAlbert Einstein College of MedicineBronxNew YorkU.S.A.
- Dominick P. Purpura Department of NeuroscienceMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
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47
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Cardas R, Iliescu C, Butoianu N, Seferian A, Gataullina S, Gargaun E, Nectoux J, Bienvenu T, Craiu D, Gidaro T, Servais L. DMD and West syndrome. Neuromuscul Disord 2017; 27:911-913. [PMID: 28802771 DOI: 10.1016/j.nmd.2017.07.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 05/10/2017] [Accepted: 07/14/2017] [Indexed: 11/28/2022]
Abstract
Duchenne Muscular Dystrophy (DMD) is the most frequent muscular dystrophy in childhood, with a worldwide incidence of one in 5000 live male births. It is due to mutations in the dystrophin gene leading to absence of full-length dystrophin protein. Central nervous system involvement is well-known in Duchenne Muscular Dystrophy. The multiple dystrophin isoforms expressed in brain have important roles in cerebral development and functioning. The association of Duchenne Muscular Dystrophy with seizures has been reported, and there is a higher prevalence of epilepsy in Duchenne Muscular Dystrophy patients (between 6.3% and 12.3%) than in the general pediatric population (0.5-1%). Duchenne Muscular Dystrophy patients may present with focal seizures, generalized tonic-clonic seizures or absences. We report on two boys in whom Duchenne Muscular Dystrophy is associated with epileptic spasms and hypsarrhythmia that fulfil the criteria for West syndrome, thus extending the spectrum of seizure types described in Duchenne Muscular Dystrophy patients.
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Affiliation(s)
- Ruxandra Cardas
- I-Motion, Platform for Pediatric Clinical Trials, Arnold Trousseau Hospital, Paris, France; "Prof. Dr. Al. Obregia" Hospital, Bucharest, Romania
| | - Catrinel Iliescu
- "Prof. Dr. Al. Obregia" Hospital, Bucharest, Romania; Clinical Neurosciences Department, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania
| | - Nina Butoianu
- "Prof. Dr. Al. Obregia" Hospital, Bucharest, Romania; Clinical Neurosciences Department, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania
| | - Andreea Seferian
- I-Motion, Platform for Pediatric Clinical Trials, Arnold Trousseau Hospital, Paris, France
| | - Svetlana Gataullina
- Service de Neuropédiatrie, Kremlin Bicêtre Hospital, Le Kremlin Bicêtre, France
| | - Elena Gargaun
- I-Motion, Platform for Pediatric Clinical Trials, Arnold Trousseau Hospital, Paris, France
| | - Juliette Nectoux
- Laboratory of Biochemistry and Molecular Genetics, HUPC Paris Centre, Cochin Hospital, Paris, France
| | - Thierry Bienvenu
- Laboratory of Biochemistry and Molecular Genetics, HUPC Paris Centre, Cochin Hospital, Paris, France
| | - Dana Craiu
- "Prof. Dr. Al. Obregia" Hospital, Bucharest, Romania; Clinical Neurosciences Department, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania
| | - Teresa Gidaro
- I-Motion, Platform for Pediatric Clinical Trials, Arnold Trousseau Hospital, Paris, France
| | - Laurent Servais
- I-Motion, Platform for Pediatric Clinical Trials, Arnold Trousseau Hospital, Paris, France; Neuromuscular Center, CHU of Liège, Liège, Belgium.
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48
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Abstract
Epileptic encephalopathies account for a large proportion of the intractable early-onset epilepsies and are characterized by frequent seizures and poor developmental outcome. The epileptic encephalopathies can be loosely divided into two related groups of named syndromes. The first comprises epilepsies where continuous EEG changes directly result in cognitive and developmental dysfunction. The second includes patients where cognitive impairment is present at seizure onset and is due to the underlying etiology but the epileptic activity may then worsen the cognitive abilities over time. Recent, large-scale exome studies have begun to establish the genetic architecture of the epileptic encephalopathies, resulting in a re-consideration of the boundaries of these named syndromes. The emergence of this genetic architecture has lead to three main pathophysiological concepts to provide a mechanistic framework for these disorders. In this article, we will review the classic syndromes, the most significant genetic findings, and relate both to the pathophysiological understanding of epileptic encephalopathies.
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49
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Kim JH, Lee JH, Lee IS, Lee SB, Cho KS. Histone Lysine Methylation and Neurodevelopmental Disorders. Int J Mol Sci 2017; 18:ijms18071404. [PMID: 28665350 PMCID: PMC5535897 DOI: 10.3390/ijms18071404] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 06/25/2017] [Accepted: 06/27/2017] [Indexed: 02/08/2023] Open
Abstract
Methylation of several lysine residues of histones is a crucial mechanism for relatively long-term regulation of genomic activity. Recent molecular biological studies have demonstrated that the function of histone methylation is more diverse and complex than previously thought. Moreover, studies using newly available genomics techniques, such as exome sequencing, have identified an increasing number of histone lysine methylation-related genes as intellectual disability-associated genes, which highlights the importance of accurate control of histone methylation during neurogenesis. However, given the functional diversity and complexity of histone methylation within the cell, the study of the molecular basis of histone methylation-related neurodevelopmental disorders is currently still in its infancy. Here, we review the latest studies that revealed the pathological implications of alterations in histone methylation status in the context of various neurodevelopmental disorders and propose possible therapeutic application of epigenetic compounds regulating histone methylation status for the treatment of these diseases.
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Affiliation(s)
- Jeong-Hoon Kim
- Personalized Genomic Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Korea.
- Department of Functional Genomics, University of Science and Technology, Daejeon 34113, Korea.
| | - Jang Ho Lee
- Department of Biological Sciences, Konkuk University, Seoul 05029, Korea.
| | - Im-Soon Lee
- Department of Biological Sciences, Konkuk University, Seoul 05029, Korea.
| | - Sung Bae Lee
- Department of Brain & Cognitive Sciences, DGIST, Daegu 42988, Korea.
| | - Kyoung Sang Cho
- Department of Biological Sciences, Konkuk University, Seoul 05029, Korea.
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50
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ARX polyalanine expansion mutations lead to migration impediment in the rostral cortex coupled with a developmental deficit of calbindin-positive cortical GABAergic interneurons. Neuroscience 2017. [PMID: 28627419 DOI: 10.1016/j.neuroscience.2017.06.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Aristaless-related homeobox gene (ARX) is indispensable for interneuron development. Patients with ARX polyalanine expansion mutations of the first two tracts (namely PA1 and PA2) suffer from intellectual disability of varying severity, with seizures a frequent comorbidity. The impact of PA1 and PA2 mutations on the brain development is unknown, hindering the search for therapeutic interventions. Here, we characterized the disturbances to cortical interneuron development in mice modeling the two most common ARX polyalanine expansion mutations in human. We found a consistent ∼40-50% reduction of calbindin-positive interneurons, but not Stt+ or Cr+ interneurons, within the cortex of newborn hemizygous mice (p=0.024) for both mutant strains compared to wildtype (p=0.011). We demonstrate that this was a consequence of calbindin precursor cells being arrested or delayed at the ventral subpallium en route of tangential migration. Ex-vivo assay validated this migration deficit in PA1 cells (p=0.0002) suggesting that the defect is contributed by intrinsic loss of Arx function within migrating cells. Both humans and mice with PA1 mutations present with severe clinical features, including intellectual disability and infantile spasms. Our data further demonstrated the pathogenic mechanism was robustly shared between PA1 and PA2 mutations, as previously reported including Arx protein reduction and overlapping transcriptome profiles within the developing mouse brains. Data from our study demonstrated that cortical calbindin interneuron development and migration is negatively affected by ARX polyalanine expansion mutations. Understanding the cellular pathogenesis contributing to disease manifestation is necessary to screen efficacy of potential therapeutic interventions.
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