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Cannilla H, Messe M, Girardin F, Borruat FX, Bally JF. Drug- and Toxin-Induced Opsoclonus - a Systematized Review, including a Case Report on Amantadine-Induced Opsoclonus in Multiple System Atrophy. Tremor Other Hyperkinet Mov (N Y) 2024; 14:23. [PMID: 38737300 PMCID: PMC11086588 DOI: 10.5334/tohm.832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 03/21/2024] [Indexed: 05/14/2024] Open
Abstract
Background Opsoclonus is a rare disorder characterized by conjugate multidirectional, horizontal, vertical, and torsional saccadic oscillations, without intersaccadic interval, resulting from dysfunction within complex neuronal pathways in the brainstem and cerebellum. While most cases of opsoclonus are associated with autoimmune or paraneoplastic disorders, infectious agents, trauma, or remain idiopathic, opsoclonus can also be caused by medications affecting neurotransmission. This review was prompted by a case of opsoclonus occurring in a patient with Multiple System Atrophy, where amantadine, an NMDA-receptor antagonist, appeared to induce opsoclonus. Methods Case report of a single patient and systematized review of toxic/drug-induced opsoclonus, selecting articles based on predefined criteria and assessing the quality of included studies. Results The review included 30 articles encompassing 158 cases of toxic/drug-induced opsoclonus. 74% of cases were attributed to bark scorpion poisoning, followed by 9% of cases associated with chlordecone intoxication. The remaining cases were due to various toxics/drugs, highlighting the involvement of various neurotransmitters, including acetylcholine, glutamate, GABA, dopamine, glycine, and sodium channels, in the development of opsoclonus. Conclusion Toxic/drug-induced opsoclonus is very rare. The diversity of toxics/drugs impacting different neurotransmitter systems makes it challenging to define a unifying mechanism, given the intricate neuronal pathways underlying eye movement physiology and opsoclonus pathophysiology.
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Affiliation(s)
| | - Maria Messe
- Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - François Girardin
- Department of ophthalmology, Jules Gonin Eye Hospital, University of Lausanne, Lausanne, Switzerland
| | - François-Xavier Borruat
- Department of ophthalmology, Jules Gonin Eye Hospital, University of Lausanne, Lausanne, Switzerland
| | - Julien F. Bally
- Service of Neurology, Department of Clinical Neurosciences, Lausanne University Hospital & University of Lausanne, Lausanne, Switzerland
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2
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Yoganathan S, Whitney R, Thomas M, Danda S, Chettali AM, Prasad AN, Farhan SMK, AlSowat D, Abukhaled M, Aldhalaan H, Gowda VK, Kinhal UV, Bylappa AY, Konanki R, Lingappa L, Parchuri BM, Appendino JP, Scantlebury MH, Cunningham J, Hadjinicolaou A, El Achkar CM, Kamate M, Menon RN, Jose M, Riordan G, Kannan L, Jain V, Manokaran RK, Chau V, Donner EJ, Costain G, Minassian BA, Jain P. KCTD7-related progressive myoclonic epilepsy: Report of 42 cases and review of literature. Epilepsia 2024; 65:709-724. [PMID: 38231304 DOI: 10.1111/epi.17880] [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: 07/14/2023] [Revised: 01/02/2024] [Accepted: 01/03/2024] [Indexed: 01/18/2024]
Abstract
OBJECTIVE KCTD7-related progressive myoclonic epilepsy (PME) is a rare autosomal-recessive disorder. This study aimed to describe the clinical details and genetic variants in a large international cohort. METHODS Families with molecularly confirmed diagnoses of KCTD7-related PME were identified through international collaboration. Furthermore, a systematic review was done to identify previously reported cases. Salient demographic, epilepsy, treatment, genetic testing, electroencephalographic (EEG), and imaging-related variables were collected and summarized. RESULTS Forty-two patients (36 families) were included. The median age at first seizure was 14 months (interquartile range = 11.75-22.5). Myoclonic seizures were frequently the first seizure type noted (n = 18, 43.9%). EEG and brain magnetic resonance imaging findings were variable. Many patients exhibited delayed development with subsequent progressive regression (n = 16, 38.1%). Twenty-one cases with genetic testing available (55%) had previously reported variants in KCTD7, and 17 cases (45%) had novel variants in KCTD7 gene. Six patients died in the cohort (age range = 1.5-21 years). The systematic review identified 23 eligible studies and further identified 59 previously reported cases of KCTD7-related disorders from the literature. The phenotype for the majority of the reported cases was consistent with a PME (n = 52, 88%). Other reported phenotypes in the literature included opsoclonus myoclonus ataxia syndrome (n = 2), myoclonus dystonia (n = 2), and neuronal ceroid lipofuscinosis (n = 3). Eight published cases died over time (14%, age range = 3-18 years). SIGNIFICANCE This study cohort and systematic review consolidated the phenotypic spectrum and natural history of KCTD7-related disorders. Early onset drug-resistant epilepsy, relentless neuroregression, and severe neurological sequalae were common. Better understanding of the natural history may help future clinical trials.
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Affiliation(s)
- Sangeetha Yoganathan
- Department of Neurological Sciences, Christian Medical College, Vellore, Tamil Nadu, India
| | - Robyn Whitney
- Comprehensive Pediatric Epilepsy Program, Division of Neurology, Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada
| | - Maya Thomas
- Department of Neurological Sciences, Christian Medical College, Vellore, Tamil Nadu, India
| | - Sumita Danda
- Department of Medical Genetics, Christian Medical College, Vellore, Tamil Nadu, India
| | | | - Asuri N Prasad
- Division of Pediatric Neurology and Clinical Neurosciences, Department of Pediatrics, Children's Hospital, London Health Sciences Centre, London, Ontario, Canada
| | - Sali M K Farhan
- Department of Neurology and Neurosurgery, and Department of Human Genetics, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Daad AlSowat
- Division of Pediatric Neurology, Neurosciences Center, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Musaad Abukhaled
- Division of Pediatric Neurology, Neurosciences Center, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Hesham Aldhalaan
- Division of Pediatric Neurology, Neurosciences Center, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Vykuntaraju K Gowda
- Department of Pediatric Neurology, Indira Gandhi Institute of Child Health, Bangalore, Karnataka, India
| | - Uddhava V Kinhal
- Department of Pediatric Neurology, Indira Gandhi Institute of Child Health, Bangalore, Karnataka, India
| | - Arun Y Bylappa
- Department of Pediatric Neurology, Indira Gandhi Institute of Child Health, Bangalore, Karnataka, India
| | - Ramesh Konanki
- Department of Pediatric Neurology, Rainbow Children's Hospital, Hyderabad, Telangana, India
| | - Lokesh Lingappa
- Department of Pediatric Neurology, Rainbow Children's Hospital, Hyderabad, Telangana, India
| | | | - Juan P Appendino
- Pediatric Neurology Service, Department of Pediatrics, Cumming School of Medicine, University of Calgary, Alberta Children's Hospital, Calgary, Alberta, Canada
| | - Morris H Scantlebury
- Departments of Pediatrics and Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Jessie Cunningham
- Hospital Library and Archives, Learning Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Aristides Hadjinicolaou
- Division of Neurology, Department of Pediatrics, CHU (Centre Hospitalier Universitaire) Sainte-Justine, Université de Montréal, Montreal, Quebec, Canada
| | - Christelle Moufawad El Achkar
- Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Mahesh Kamate
- Department of Pediatric Neurology, Jawaharlal Nehru Medical College, KLE (Karnataka Lingayat Education) Academy of Higher Education and Research, KLE's Dr Prabhakar Kore (PK) Hospital, Belagavi, Karnataka, India
| | - Ramshekhar N Menon
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences & Technology, Thiruvananthapuram, Kerala, India
| | - Manna Jose
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences & Technology, Thiruvananthapuram, Kerala, India
| | - Gillian Riordan
- Department of Paediatric Neurology, Red Cross War Memorial Children's Hospital, University of Cape Town, Cape Town, South Africa
| | | | - Vivek Jain
- Department of Pediatric Neurology, Neoclinic Children's Hospital, Jaipur, Rajasthan, India
| | - Ranjith Kumar Manokaran
- Division of Pediatric neurology, Department of Neurology, Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India
| | - Vann Chau
- Division of Neurology, Department of Pediatrics, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Elizabeth J Donner
- Epilepsy Program, Division of Neurology, Department of Pediatrics, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Gregory Costain
- Division of Clinical and Metabolic Genetics, Hospital for Sick Children, and Program in Genetics & Genome Biology, SickKids Research Institute, Toronto, Ontario, Canada
| | - Berge A Minassian
- Division of Neurology, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Puneet Jain
- Epilepsy Program, Division of Neurology, Department of Pediatrics, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
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Sharma J, Mulherkar S, Chen UI, Xiong Y, Bajaj L, Cho BK, Goo YA, Leung HCE, Tolias KF, Sardiello M. Calpain activity is negatively regulated by a KCTD7-Cullin-3 complex via non-degradative ubiquitination. Cell Discov 2023; 9:32. [PMID: 36964131 PMCID: PMC10038992 DOI: 10.1038/s41421-023-00533-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 02/24/2023] [Indexed: 03/26/2023] Open
Abstract
Calpains are a class of non-lysosomal cysteine proteases that exert their regulatory functions via limited proteolysis of their substrates. Similar to the lysosomal and proteasomal systems, calpain dysregulation is implicated in the pathogenesis of neurodegenerative disease and cancer. Despite intensive efforts placed on the identification of mechanisms that regulate calpains, however, calpain protein modifications that regulate calpain activity are incompletely understood. Here we show that calpains are regulated by KCTD7, a cytosolic protein of previously uncharacterized function whose pathogenic mutations result in epilepsy, progressive ataxia, and severe neurocognitive deterioration. We show that KCTD7 works in complex with Cullin-3 and Rbx1 to execute atypical, non-degradative ubiquitination of calpains at specific sites (K398 of calpain 1, and K280 and K674 of calpain 2). Experiments based on single-lysine mutants of ubiquitin determined that KCTD7 mediates ubiquitination of calpain 1 via K6-, K27-, K29-, and K63-linked chains, whereas it uses K6-mediated ubiquitination to modify calpain 2. Loss of KCTD7-mediated ubiquitination of calpains led to calpain hyperactivation, aberrant cleavage of downstream targets, and caspase-3 activation. CRISPR/Cas9-mediated knockout of Kctd7 in mice phenotypically recapitulated human KCTD7 deficiency and resulted in calpain hyperactivation, behavioral impairments, and neurodegeneration. These phenotypes were largely prevented by pharmacological inhibition of calpains, thus demonstrating a major role of calpain dysregulation in KCTD7-associated disease. Finally, we determined that Cullin-3-KCTD7 mediates ubiquitination of all ubiquitous calpains. These results unveil a novel mechanism and potential target to restrain calpain activity in human disease and shed light on the molecular pathogenesis of KCTD7-associated disease.
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Affiliation(s)
- Jaiprakash Sharma
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA.
- Department of Pediatrics, Washington University in St. Louis, School of Medicine, Genetics and Genomic Medicine, Saint Louis, MO, USA.
| | - Shalaka Mulherkar
- Department of Pediatrics, Washington University in St. Louis, School of Medicine, Genetics and Genomic Medicine, Saint Louis, MO, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Uan-I Chen
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Yan Xiong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
- Department of Pediatrics, Washington University in St. Louis, School of Medicine, Genetics and Genomic Medicine, Saint Louis, MO, USA
| | - Lakshya Bajaj
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Byoung-Kyu Cho
- Mass Spectrometry Technology Access Center at the McDonnell Genome Institute, Washington University in St. Louis, School of Medicine, St. Louis, MO, USA
| | - Young Ah Goo
- Mass Spectrometry Technology Access Center at the McDonnell Genome Institute, Washington University in St. Louis, School of Medicine, St. Louis, MO, USA
- Department of Biochemistry and Molecular Biophysics, Department of Genetics, Washington University School of Medicine, St. Louis, MO, USA
| | - Hon-Chiu Eastwood Leung
- Departments of Medicine, Pediatrics, and Molecular and Cellular Biology, Dan Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Kimberley F Tolias
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Verna and Marrs McLean Department of Biochemistry and Molecular Cell Biology, Baylor College of Medicine, Houston, TX, USA
| | - Marco Sardiello
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA.
- Department of Pediatrics, Washington University in St. Louis, School of Medicine, Genetics and Genomic Medicine, Saint Louis, MO, USA.
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Liang JH, Alevy J, Akhanov V, Seo R, Massey CA, Jiang D, Zhou J, Sillitoe RV, Noebels JL, Samuel MA. Kctd7 deficiency induces myoclonic seizures associated with Purkinje cell death and microvascular defects. Dis Model Mech 2022; 15:dmm049642. [PMID: 35972048 PMCID: PMC9509889 DOI: 10.1242/dmm.049642] [Citation(s) in RCA: 4] [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: 05/05/2022] [Accepted: 07/29/2022] [Indexed: 01/27/2023] Open
Abstract
Mutations in the potassium channel tetramerization domain-containing 7 (KCTD7) gene are associated with a severe neurodegenerative phenotype characterized by childhood onset of progressive and intractable myoclonic seizures accompanied by developmental regression. KCTD7-driven disease is part of a large family of progressive myoclonic epilepsy syndromes displaying a broad spectrum of clinical severity. Animal models of KCTD7-related disease are lacking, and little is known regarding how KCTD7 protein defects lead to epilepsy and cognitive dysfunction. We characterized Kctd7 expression patterns in the mouse brain during development and show that it is selectively enriched in specific regions as the brain matures. We further demonstrate that Kctd7-deficient mice develop seizures and locomotor defects with features similar to those observed in human KCTD7-associated diseases. We also show that Kctd7 is required for Purkinje cell survival in the cerebellum and that selective degeneration of these neurons is accompanied by defects in cerebellar microvascular organization and patterning. Taken together, these results define a new model for KCTD7-associated epilepsy and identify Kctd7 as a modulator of neuron survival and excitability linked to microvascular alterations in vulnerable regions.
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Affiliation(s)
- Justine H. Liang
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jonathan Alevy
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA
| | - Viktor Akhanov
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ryan Seo
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Developmental Neurogenetics Laboratory, Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Human and Molecular Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Cory A. Massey
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Developmental Neurogenetics Laboratory, Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Human and Molecular Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Danye Jiang
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA
| | - Joy Zhou
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, Houston, TX 77030, USA
| | - Roy V. Sillitoe
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, Houston, TX 77030, USA
| | - Jeffrey L. Noebels
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Developmental Neurogenetics Laboratory, Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Human and Molecular Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Melanie A. Samuel
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA
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5
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Teive HAG, Cassou E, Coutinho L, Camargo CHF, Munhoz RP. Ramsay Hunt syndrome: New impressions in the era of molecular genetics. Parkinsonism Relat Disord 2022; 97:101-104. [PMID: 35430109 DOI: 10.1016/j.parkreldis.2022.04.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/22/2022] [Accepted: 04/04/2022] [Indexed: 11/27/2022]
Abstract
More frequent use of next-generation sequencing led to a paradigm shift in assessing heredodegenerative diseases. This is particularly notable in progressive myoclonus epilepsy (PME) and progressive myoclonus ataxia (PMA) where a group of disorders linked to novel genetic mutations has now been added to these phenotypical realms. Despite the historical value of Ramsay Hunt's contribution defining the syndrome later known as PMA, recent genetic developments have made this eponym obsolete and a new definition and classification of PMA and PME seem necessary. A rational possibility is to adopt the wider term progressive myoclonus ataxia and epilepsy syndrome (PMAES), which can be subdivided into its main subtypes, PME and PMA, whenever clinical data is sufficient to make that distinction.
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Affiliation(s)
- Hélio A G Teive
- Movement Disorders Unit, Neurology Service, Internal Medicine Department, Hospital de Clínicas, Federal University of Paraná, Curitiba, Paraná, Brazil; Neurodegenerative Diseases Group, Postgraduate Program in Internal Medicine, Hospital de Clínicas, Federal University of Paraná, Curitiba, Paraná, Brazil.
| | - Emanuel Cassou
- Movement Disorders Unit, Neurology Service, Internal Medicine Department, Hospital de Clínicas, Federal University of Paraná, Curitiba, Paraná, Brazil.
| | - Léo Coutinho
- Movement Disorders Unit, Neurology Service, Internal Medicine Department, Hospital de Clínicas, Federal University of Paraná, Curitiba, Paraná, Brazil.
| | - Carlos Henrique F Camargo
- Neurodegenerative Diseases Group, Postgraduate Program in Internal Medicine, Hospital de Clínicas, Federal University of Paraná, Curitiba, Paraná, Brazil.
| | - Renato P Munhoz
- Movement Disorders Centre, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada.
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6
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Sun Q, Wang Y, Xie Y, Wu P, Li S, Zhao W. Long-term neurological outcomes of children with neuroblastoma with opsoclonus-myoclonus syndrome. Transl Pediatr 2022; 11:368-374. [PMID: 35378965 PMCID: PMC8976687 DOI: 10.21037/tp-21-519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 02/22/2022] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Neuroblastoma with opsoclonus-myoclonus syndrome (OMS-NB) is a rare disease in children. Few studies of long-term outcome of children with OMS-NB were conducted. This study aimed to review the rate of recovery of neurological symptoms and the long-term neurological outcomes of children with OMS-NB. METHODS This study retrospectively assessed 14 children with OMS-NB diagnosed at Peking University First Hospital from May 2011 to November 2019. Demographic data, neurological symptoms, oncological status and treatments were retrospectively reviewed from the records. Neurological sequelae were recorded by clinical and remote follow-up. RESULTS During the acute stage, myoclonus and ataxia were observed in all children while opsoclonus was observed in 10/14 children. The median durations of neurological symptoms were 15 months (range, 5-48 months). Approximately 93% (13/14) children revealed neurological sequelae. Significant correlations were as follows: motor retardation with female gender (P<0.001) and residual tumors (P<0.05); language impairment with non-adrenal-gland-located tumors (P<0.05). There were no obvious factors that had a statistical relationship with cognitive disorder or behavioral changes. CONCLUSIONS Children with OMS-NB have favorable outcomes in terms of neurological symptoms. Neurological sequelae occurred in almost all children. Children with different features tend to reveal different sequalae. Features of female gender and residual tumors tend to reveal motor retardation while that of non-adrenal-gland-located tumors tend to reveal language impairment.
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Affiliation(s)
- Qing Sun
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yinhao Wang
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China
| | - Yao Xie
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Penghui Wu
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Shuo Li
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Weihong Zhao
- Department of Pediatrics, Peking University First Hospital, Beijing, China
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7
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Gardner E, Mole SE. The Genetic Basis of Phenotypic Heterogeneity in the Neuronal Ceroid Lipofuscinoses. Front Neurol 2021; 12:754045. [PMID: 34733232 PMCID: PMC8558747 DOI: 10.3389/fneur.2021.754045] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 09/20/2021] [Indexed: 12/12/2022] Open
Abstract
The neuronal ceroid lipofuscinoses (NCLs) are a group of inherited neurodegenerative disorders that affect children and adults. They share some similar clinical features and the accumulation of autofluorescent storage material. Since the discovery of the first causative genes, more than 530 mutations have been identified across 13 genes in cases diagnosed with NCL. These genes encode a variety of proteins whose functions have not been fully defined; most are lysosomal enzymes, or transmembrane proteins of the lysosome or other organelles. Many mutations in these genes are associated with a typical NCL disease phenotype. However, increasing numbers of variant disease phenotypes are being described, affecting age of onset, severity or progression, and including some distinct clinical phenotypes. This data is collated by the NCL Mutation Database which allows analysis from many perspectives. This article will summarise and interpret current knowledge and understanding of their genetic basis and phenotypic heterogeneity.
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Affiliation(s)
- Emily Gardner
- MRC Laboratory for Molecular Cell Biology and Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Sara E Mole
- MRC Laboratory for Molecular Cell Biology and Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
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8
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Binaafar S, Garshasbi M, Tavasoli AR, Badv RS, Hosseiny SMM, Samanta D, Rabbani B, Mahdieh N. Nonsyndromic Early-Onset Epileptic Encephalopathies: Two Novel KCTD7 Pathogenic Variants and a Literature Review. Dev Neurosci 2021; 43:348-357. [PMID: 34469883 DOI: 10.1159/000519318] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 08/30/2021] [Indexed: 11/19/2022] Open
Abstract
Early-onset epileptic encephalopathies (EOEE) affect cognitive, sensory, and motor development. Genetic variations are among the identifiable primary causes of these syndromes. However, some patients have been reported to be affected by EOEE without any other clinical symptoms and signs. We study the genotype and phenotype of patients with nonsyndromic early-onset epileptic encephalopathy (NSEOEE) and report 2 novel patients from Iran. A comprehensive search was conducted in PubMed, John Willy, Springer, Elsevier, and Google Scholar databases to collect related information of all the previously reported cases with KCTD7 mutations. Fifty-four patients (from 40 families) were investigated. Using trio-whole-exome sequencing (trio-WES) and Sanger sequencing, the possible genetic causes of the disorder were checked. The probable impacts of the identified variants on the KCTD7 protein structure and function were predicted. This study provided a detailed overview of all published KCTD7 mutations and 2 de novo ones. We identified 2 novel homozygous variants of uncertain significance, c.458 G > A p. Arg153His and c.529C > T (p.Arg177Cys), in KCTD7 (NM_153033.4) (Chr7(GRCh37)). There is a significant wide distribution of the KCTD7 gene causing NSEOEE among different populations. In conclusion, KCTD7 mutations demonstrate a diverse geographical distribution alongside a wide range of ethnicities. This highlights the importance of careful consideration in the WES data analysis. Mutations of this gene may be a common cause of NSEOEE. Also, this study imprints targeted therapeutic opportunities for potassium channelepsies such as KCTD7-related NSEOEE.
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Affiliation(s)
- Sima Binaafar
- Growth and Development Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Masoud Garshasbi
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Ali Reza Tavasoli
- Myelin Disorders Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Reza Shervin Badv
- Children's Hospital Center, Pediatric Center of Excellence, Tehran University of Medical Center, Tehran, Iran
| | - Seyyed Mohammad Mahdi Hosseiny
- Myelin Disorders Clinic, Pediatric Neurology Division, Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Debopam Samanta
- Child Neurology Section, Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Bahareh Rabbani
- Growth and Development Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Nejat Mahdieh
- Growth and Development Research Center, Tehran University of Medical Sciences, Tehran, Iran.,Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
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9
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Burke EA, Sturgeon M, Zastrow DB, Fernandez L, Prybol C, Marwaha S, Frothingham EP, Ward PA, Eng CM, Fresard L, Montgomery SB, Enns GM, Fisher PG, Wolfe LA, Harding B, Carrington B, Bishop K, Sood R, Huang Y, Elkahloun A, Toro C, Bassuk AG, Wheeler MT, Markello TC, Gahl WA, Malicdan MCV. Compound heterozygous KCTD7 variants in progressive myoclonus epilepsy. J Neurogenet 2021; 35:74-83. [PMID: 33970744 DOI: 10.1080/01677063.2021.1892095] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
KCTD7 is a member of the potassium channel tetramerization domain-containing protein family and has been associated with progressive myoclonic epilepsy (PME), characterized by myoclonus, epilepsy, and neurological deterioration. Here we report four affected individuals from two unrelated families in which we identified KCTD7 compound heterozygous single nucleotide variants through exome sequencing. RNAseq was used to detect a non-annotated splicing junction created by a synonymous variant in the second family. Whole-cell patch-clamp analysis of neuroblastoma cells overexpressing the patients' variant alleles demonstrated aberrant potassium regulation. While all four patients experienced many of the common clinical features of PME, they also showed variable phenotypes not previously reported, including dysautonomia, brain pathology findings including a significantly reduced thalamus, and the lack of myoclonic seizures. To gain further insight into the pathogenesis of the disorder, zinc finger nucleases were used to generate kctd7 knockout zebrafish. Kctd7 homozygous mutants showed global dysregulation of gene expression and increased transcription of c-fos, which has previously been correlated with seizure activity in animal models. Together these findings expand the known phenotypic spectrum of KCTD7-associated PME, report a new animal model for future studies, and contribute valuable insights into the disease.
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Affiliation(s)
- Elizabeth A Burke
- NIH Undiagnosed Diseases Program, Common Fund, Office of the Director, NIH and National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Morgan Sturgeon
- Department of Pediatrics, University of Iowa, Iowa City, IA, USA
| | - Diane B Zastrow
- Center for Undiagnosed Diseases, Stanford University School of Medicine, Stanford, CA, USA
| | - Liliana Fernandez
- Center for Undiagnosed Diseases, Stanford University School of Medicine, Stanford, CA, USA
| | - Cameron Prybol
- Center for Undiagnosed Diseases, Stanford University School of Medicine, Stanford, CA, USA
| | - Shruti Marwaha
- Center for Undiagnosed Diseases, Stanford University School of Medicine, Stanford, CA, USA
| | | | - Patricia A Ward
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Christine M Eng
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Laure Fresard
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - Stephen B Montgomery
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA.,Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA
| | - Gregory M Enns
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA
| | - Paul G Fisher
- Center for Undiagnosed Diseases, Stanford University School of Medicine, Stanford, CA, USA.,Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA.,Department of Neurology, Stanford University School of Medicine, Stanford, CA, USA
| | - Lynne A Wolfe
- NIH Undiagnosed Diseases Program, Common Fund, Office of the Director, NIH and National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Brian Harding
- Departments of Pathology and Lab Medicine (Neuropathology), Children's Hospital of Philadelphia and the Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Blake Carrington
- Zebrafish Core, Translational and Functional Genomics Branch, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Kevin Bishop
- Zebrafish Core, Translational and Functional Genomics Branch, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Raman Sood
- Zebrafish Core, Translational and Functional Genomics Branch, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Yan Huang
- NIH Undiagnosed Diseases Program, Common Fund, Office of the Director, NIH and National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Abdel Elkahloun
- Microarray Core, Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Camilo Toro
- NIH Undiagnosed Diseases Program, Common Fund, Office of the Director, NIH and National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | | | - Matthew T Wheeler
- Center for Undiagnosed Diseases, Stanford University School of Medicine, Stanford, CA, USA
| | - Thomas C Markello
- NIH Undiagnosed Diseases Program, Common Fund, Office of the Director, NIH and National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - William A Gahl
- NIH Undiagnosed Diseases Program, Common Fund, Office of the Director, NIH and National Human Genome Research Institute, NIH, Bethesda, MD, USA.,Medical Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - May Christine V Malicdan
- NIH Undiagnosed Diseases Program, Common Fund, Office of the Director, NIH and National Human Genome Research Institute, NIH, Bethesda, MD, USA
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10
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Bhatia P, Heim J, Cornejo P, Kane L, Santiago J, Kruer MC. Opsoclonus-myoclonus-ataxia syndrome in children. J Neurol 2021; 269:750-757. [PMID: 33779841 DOI: 10.1007/s00415-021-10536-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/24/2021] [Accepted: 03/25/2021] [Indexed: 12/31/2022]
Abstract
Opsoclonus-myoclonus-ataxia syndrome is a rare neuroimmunologic disorder typically presenting in previously healthy infants and toddlers. It is characterized by a clinical triad of (1) erratic saccadic intrusions; (2) myoclonus and/or ataxia; (3) behavioral features, typified by developmental plateauing, irritability and insomnia. About half of cases are associated with an underlying neuroblastoma and diagnostic imaging is essential once OMAS is suspected. A thorough workup, including serum, urine, and cerebrospinal fluid studies is critical to identify underlying biomarkers of OMAS itself or neuroblastoma. Historically, many children had relatively poor long-term outcomes, with residual neurologic and/or neuropsychiatry sequelae typical. More recent concepts have emphasized combined immunotherapy regimens that offer hope for better outcomes in children with this remarkable, challenging disease.
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Affiliation(s)
- Poonam Bhatia
- Pediatric Movement Disorders Program, Barrow Neurological Institute, Phoenix Children's Hospital, 1919 E Thomas Rd, Phoenix, AZ, 85016, USA.,Department of Radiology, Phoenix Children's Hospital, Phoenix, AZ, USA
| | - Jennifer Heim
- Pediatric Movement Disorders Program, Barrow Neurological Institute, Phoenix Children's Hospital, 1919 E Thomas Rd, Phoenix, AZ, 85016, USA
| | - Patricia Cornejo
- Department of Radiology, Phoenix Children's Hospital, Phoenix, AZ, USA
| | - Lauren Kane
- Pediatric Movement Disorders Program, Barrow Neurological Institute, Phoenix Children's Hospital, 1919 E Thomas Rd, Phoenix, AZ, 85016, USA.,Pediatric Neuroimmunology Program, Barrow Neurological Institute, Phoenix Children's Hospital, Phoenix, AZ, USA
| | - Jason Santiago
- Pediatric Movement Disorders Program, Barrow Neurological Institute, Phoenix Children's Hospital, 1919 E Thomas Rd, Phoenix, AZ, 85016, USA
| | - Michael C Kruer
- Pediatric Movement Disorders Program, Barrow Neurological Institute, Phoenix Children's Hospital, 1919 E Thomas Rd, Phoenix, AZ, 85016, USA. .,Pediatric Neuroimmunology Program, Barrow Neurological Institute, Phoenix Children's Hospital, Phoenix, AZ, USA. .,Department of Child Health, University of Arizona College of Medicine - Phoenix, Phoenix, AZ, USA.
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11
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Chen X, Liu G, Wang S, Zhang H, Xue P. Machine learning analysis of gene expression profile reveals a novel diagnostic signature for osteoporosis. J Orthop Surg Res 2021; 16:189. [PMID: 33722258 PMCID: PMC7958453 DOI: 10.1186/s13018-021-02329-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 03/01/2021] [Indexed: 01/25/2023] Open
Abstract
Background Osteoporosis (OP) is increasingly prevalent with the aging of the world population. It is urgent to identify efficient diagnostic signatures for the clinical application. Method We downloaded the mRNA profile of 90 peripheral blood samples with or without OP from GEO database (Number: GSE152073). Weighted gene co-expression network analysis (WGCNA) was used to reveal the correlation among genes in all samples. GO term and KEGG pathway enrichment analysis was performed via the clusterProfiler R package. STRING database was applied to screen the interaction pairs among proteins. Protein–protein interaction (PPI) network was visualized based on Cytoscape, and the key genes were screened using the cytoHubba plug-in. The diagnostic model based on these key genes was constructed, and 5-fold cross validation method was applied to evaluate its reliability. Results A gene module consisted of 176 genes predicted to be associated with the occurrence of OP was identified. A total of 16 significantly enriched GO terms and 1 significantly enriched KEGG pathway were obtained based on the 176 genes. The top 50 key genes in the PPI network were identified. Then 22 genes were screened based on stepwise regression analysis from the 50 key genes. Of which, 9 genes were further screened out by multivariate regression analysis with the significant threshold of P value < 0.01. The diagnostic model was established based on the optimal 9 key genes, which efficiently separated the normal samples and OP samples. Conclusion A diagnostic model established based on nine key genes could reliably separate OP patients from healthy subjects, which provided novel lightings on the diagnostic research of OP. Supplementary Information The online version contains supplementary material available at 10.1186/s13018-021-02329-1.
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Affiliation(s)
- Xinlei Chen
- Department of Orthopedics, Zibo Central Hospital, Zibo, 255000, Shandong, China
| | - Guangping Liu
- Department of Orthopedics, Zibo Central Hospital, Zibo, 255000, Shandong, China
| | - Shuxiang Wang
- Department of Orthopedics, Zibo Central Hospital, Zibo, 255000, Shandong, China
| | - Haiyang Zhang
- Department of Orthopedics, Zibo Central Hospital, Zibo, 255000, Shandong, China
| | - Peng Xue
- Department of Orthopedics, Zibo Central Hospital, Zibo, 255000, Shandong, China.
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12
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Dudipala SC, M P, Chennadi AK. A Novel Mutation in KCDT7 Gene in an Indian Girl With Progressive Myoclonus Epilepsy. Cureus 2021; 13:e13447. [PMID: 33767931 PMCID: PMC7982382 DOI: 10.7759/cureus.13447] [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] [Indexed: 01/13/2023] Open
Abstract
The progressive myoclonus epilepsy (PME) is a rare group of clinically and genetically heterogeneous disorders characterized by myoclonus, drug refractory epilepsy, and neurological deterioration. Here, we report a three-year-old female patient with neuroregression after a period of normal development and uncontrollable myoclonic seizures, which fulfill the criteria of PME. Next-generation sequencing revealed a novel homozygous mutation of variant c.173G>C in exon 2 of the KCDT7 (potassium channel tetramerization domain containing protein 7) gene that was compatible with the diagnosis of progressive myoclonic epilepsy 3 (PME3) with or without intracellular inclusions. This is a rare report of KCTD7 mutations causing PME in the Indian population. Our findings supported the important role of KCTD7 in PME and broadened the mutation spectrum.
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Affiliation(s)
- Sai Chandar Dudipala
- Pediatric Neurology, Star Women & Children Hospital, Karimnagar, IND.,Pediatrics, Prathima Institute of Medical Sciences, Karimnagar, IND
| | - Prashanthi M
- Pediatrics, Prathima Institute of Medical Sciences, Karimnagar, IND
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13
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Asmar AJ, Beck DB, Werner A. Control of craniofacial and brain development by Cullin3-RING ubiquitin ligases: Lessons from human disease genetics. Exp Cell Res 2020; 396:112300. [PMID: 32986984 PMCID: PMC10627151 DOI: 10.1016/j.yexcr.2020.112300] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 09/16/2020] [Accepted: 09/20/2020] [Indexed: 12/19/2022]
Abstract
Metazoan development relies on intricate cell differentiation, communication, and migration pathways, which ensure proper formation of specialized cell types, tissues, and organs. These pathways are crucially controlled by ubiquitylation, a reversible post-translational modification that regulates the stability, activity, localization, or interaction landscape of substrate proteins. Specificity of ubiquitylation is ensured by E3 ligases, which bind substrates and co-operate with E1 and E2 enzymes to mediate ubiquitin transfer. Cullin3-RING ligases (CRL3s) are a large class of multi-subunit E3s that have emerged as important regulators of cell differentiation and development. In particular, recent evidence from human disease genetics, animal models, and mechanistic studies have established their involvement in the control of craniofacial and brain development. Here, we summarize regulatory principles of CRL3 assembly, substrate recruitment, and ubiquitylation that allow this class of E3s to fulfill their manifold functions in development. We further review our current mechanistic understanding of how specific CRL3 complexes orchestrate neuroectodermal differentiation and highlight diseases associated with their dysregulation. Based on evidence from human disease genetics, we propose that other unknown CRL3 complexes must help coordinate craniofacial and brain development and discuss how combining emerging strategies from the field of disease gene discovery with biochemical and human pluripotent stem cell approaches will likely facilitate their identification.
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Affiliation(s)
- Anthony J Asmar
- Stem Cell Biochemistry Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, 20892, USA
| | - David B Beck
- Stem Cell Biochemistry Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, 20892, USA; Metabolic, Cardiovascular and Inflammatory Disease Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Achim Werner
- Stem Cell Biochemistry Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, 20892, USA.
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14
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Rossi M, van der Veen S, Merello M, Tijssen MAJ, van de Warrenburg B. Myoclonus-Ataxia Syndromes: A Diagnostic Approach. Mov Disord Clin Pract 2020; 8:9-24. [PMID: 33426154 DOI: 10.1002/mdc3.13106] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 09/30/2020] [Accepted: 10/14/2020] [Indexed: 12/30/2022] Open
Abstract
Background A myriad of disorders combine myoclonus and ataxia. Most causes are genetic and an increasing number of genes are being associated with myoclonus-ataxia syndromes (MAS), due to recent advances in genetic techniques. A proper etiologic diagnosis of MAS is clinically relevant, given the consequences for genetic counseling, treatment, and prognosis. Objectives To review the causes of MAS and to propose a diagnostic algorithm. Methods A comprehensive and structured literature search following PRISMA criteria was conducted to identify those disorders that may combine myoclonus with ataxia. Results A total of 135 causes of combined myoclonus and ataxia were identified, of which 30 were charted as the main causes of MAS. These include four acquired entities: opsoclonus-myoclonus-ataxia syndrome, celiac disease, multiple system atrophy, and sporadic prion diseases. The distinction between progressive myoclonus epilepsy and progressive myoclonus ataxia poses one of the main diagnostic dilemmas. Conclusions Diagnostic algorithms for pediatric and adult patients, based on clinical manifestations including epilepsy, are proposed to guide the differential diagnosis and corresponding work-up of the most important and frequent causes of MAS. A list of genes associated with MAS to guide genetic testing strategies is provided. Priority should be given to diagnose or exclude acquired or treatable disorders.
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Affiliation(s)
- Malco Rossi
- Movement Disorders Section Neuroscience Department Buenos Aires Argentina.,Argentine National Scientific and Technological Research Council (CONICET) Buenos Aires Argentina
| | - Sterre van der Veen
- Pontificia Universidad Católica Argentina (UCA) Buenos Aires Argentina.,Department of Neurology University of Groningen, University Medical Center Groningen Groningen The Netherlands
| | - Marcelo Merello
- Movement Disorders Section Neuroscience Department Buenos Aires Argentina.,Argentine National Scientific and Technological Research Council (CONICET) Buenos Aires Argentina.,Pontificia Universidad Católica Argentina (UCA) Buenos Aires Argentina
| | - Marina A J Tijssen
- Department of Neurology University of Groningen, University Medical Center Groningen Groningen The Netherlands.,Expertise Center Movement Disorders Groningen University Medical Center Groningen (UMCG) Groningen The Netherlands
| | - Bart van de Warrenburg
- Department of Neurology, Donders Institute for Brain, Cognition & Behaviour Radboud University Medical Center Nijmegen The Netherlands
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15
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Bauwens M, Storch S, Weisschuh N, Ceuterick‐de Groote C, De Rycke R, Guillemyn B, De Jaegere S, Coppieters F, Van Coster R, Leroy BP, De Baere E. Functional characterization of novel MFSD8 pathogenic variants anticipates neurological involvement in juvenile isolated maculopathy. Clin Genet 2020; 97:426-436. [PMID: 31721179 PMCID: PMC7064892 DOI: 10.1111/cge.13673] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 10/30/2019] [Accepted: 11/01/2019] [Indexed: 12/22/2022]
Abstract
Biallelic MFSD8 variants are an established cause of severe late-infantile subtype of neuronal ceroid lipofuscinosis (v-LINCL), a severe lysosomal storage disorder, but have also been associated with nonsyndromic adult-onset maculopathy. Here, we functionally characterized two novel MFSD8 variants found in a child with juvenile isolated maculopathy, in order to establish a refined prognosis. ABCA4 locus resequencing was followed by the analysis of other inherited retinal disease genes by whole exome sequencing (WES). Minigene assays and cDNA sequencing were used to assess the effect of a novel MFSD8 splice variant. MFSD8 expression was quantified with qPCR and overexpression studies were analyzed by immunoblotting. Transmission electron microscopy (TEM) was performed on a skin biopsy and ophthalmological and neurological re-examinations were conducted. WES revealed two novel MFSD8 variants: c.[590del];[439+3A>C] p.[Gly197Valfs*2];[Ile67Glufs*3]. Characterization of the c.439+3A>C variant via splice assays showed exon-skipping (p.Ile67Glufs*3), while overexpression studies of the corresponding protein indicated expression of a truncated polypeptide. In addition, a significantly reduced MFSD8 RNA expression was noted in patient's lymphocytes. TEM of a skin biopsy revealed typical v-LINCL lipopigment inclusions while neurological imaging of the proband displayed subtle cerebellar atrophy. Functional characterization demonstrated the pathogenicity of two novel MFSD8 variants, found in a child with an initial diagnosis of juvenile isolated maculopathy but likely evolving to v-LINCL with a protracted disease course. Our study allowed a refined neurological prognosis in the proband and expands the natural history of MFSD8-associated disease.
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Affiliation(s)
| | - Stephan Storch
- Department of Biochemistry, Children's HospitalUniversity Medical Center Hamburg‐EppendorfHamburgGermany
| | - Nicole Weisschuh
- Molecular Genetics Laboratory, Institute for Ophthalmic ResearchUniversity of TuebingenTuebingenGermany
| | | | - Riet De Rycke
- Department of Biomedical Molecular BiologyGhent UniversityGhentBelgium
- VIB‐UGent Center for Inflammation ResearchGhentBelgium
- Ghent University Expertise Centre for Transmission Electron Microscopy and VIB BioImaging CoreGhentBelgium
| | | | - Sarah De Jaegere
- Center for Medical GeneticsGhent University HospitalGhentBelgium
| | | | - Rudy Van Coster
- Department of Pediatrics, Division of Pediatric Neurology and MetabolismGhent University HospitalGhentBelgium
| | - Bart P. Leroy
- Center for Medical GeneticsGhent University HospitalGhentBelgium
- Department of OphthalmologyGhent University and Ghent University HospitalGhentBelgium
- Division of Ophthalmology and Center for Cellular & Molecular TherapeuticsThe Children's Hospital of PhiladelphiaPhiladelphiaPennsylvania
| | - Elfride De Baere
- Center for Medical GeneticsGhent UniversityGhentBelgium
- Center for Medical GeneticsGhent University HospitalGhentBelgium
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16
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Mastrangelo M, Sartori S, Simonati A, Brinciotti M, Moro F, Nosadini M, Pezzini F, Doccini S, Santorelli FM, Leuzzi V. Progressive myoclonus epilepsy and ceroidolipofuscinosis 14: The multifaceted phenotypic spectrum of KCTD7-related disorders. Eur J Med Genet 2019; 62:103591. [DOI: 10.1016/j.ejmg.2018.11.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 09/28/2018] [Accepted: 11/22/2018] [Indexed: 11/27/2022]
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17
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Teng X, Aouacheria A, Lionnard L, Metz KA, Soane L, Kamiya A, Hardwick JM. KCTD: A new gene family involved in neurodevelopmental and neuropsychiatric disorders. CNS Neurosci Ther 2019; 25:887-902. [PMID: 31197948 PMCID: PMC6566181 DOI: 10.1111/cns.13156] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 05/02/2019] [Accepted: 05/13/2019] [Indexed: 12/12/2022] Open
Abstract
The underlying molecular basis for neurodevelopmental or neuropsychiatric disorders is not known. In contrast, mechanistic understanding of other brain disorders including neurodegeneration has advanced considerably. Yet, these do not approach the knowledge accrued for many cancers with precision therapeutics acting on well-characterized targets. Although the identification of genes responsible for neurodevelopmental and neuropsychiatric disorders remains a major obstacle, the few causally associated genes are ripe for discovery by focusing efforts to dissect their mechanisms. Here, we make a case for delving into mechanisms of the poorly characterized human KCTD gene family. Varying levels of evidence support their roles in neurocognitive disorders (KCTD3), neurodevelopmental disease (KCTD7), bipolar disorder (KCTD12), autism and schizophrenia (KCTD13), movement disorders (KCTD17), cancer (KCTD11), and obesity (KCTD15). Collective knowledge about these genes adds enhanced value, and critical insights into potential disease mechanisms have come from unexpected sources. Translation of basic research on the KCTD-related yeast protein Whi2 has revealed roles in nutrient signaling to mTORC1 (KCTD11) and an autophagy-lysosome pathway affecting mitochondria (KCTD7). Recent biochemical and structure-based studies (KCTD12, KCTD13, KCTD16) reveal mechanisms of regulating membrane channel activities through modulation of distinct GTPases. We explore how these seemingly varied functions may be disease related.
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Affiliation(s)
- Xinchen Teng
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical SciencesSoochow UniversitySuzhouChina
- W. Harry Feinstone Department of Molecular Microbiology and ImmunologyJohns Hopkins University Bloomberg School of Public HealthBaltimoreMaryland
| | - Abdel Aouacheria
- ISEM, Institut des Sciences de l'Evolution de Montpellier, CNRS, EPHE, IRDUniversité de MontpellierMontpellierFrance
| | - Loïc Lionnard
- ISEM, Institut des Sciences de l'Evolution de Montpellier, CNRS, EPHE, IRDUniversité de MontpellierMontpellierFrance
| | - Kyle A. Metz
- W. Harry Feinstone Department of Molecular Microbiology and ImmunologyJohns Hopkins University Bloomberg School of Public HealthBaltimoreMaryland
- Present address:
Feinberg School of MedicineNorthwestern UniversityChicagoUSA
| | - Lucian Soane
- W. Harry Feinstone Department of Molecular Microbiology and ImmunologyJohns Hopkins University Bloomberg School of Public HealthBaltimoreMaryland
| | - Atsushi Kamiya
- Department of Psychiatry and Behavioral SciencesJohns Hopkins School of MedicineBaltimoreMaryland
| | - J. Marie Hardwick
- W. Harry Feinstone Department of Molecular Microbiology and ImmunologyJohns Hopkins University Bloomberg School of Public HealthBaltimoreMaryland
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18
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Alevy J, Burger CA, Albrecht NE, Jiang D, Samuel MA. Progressive myoclonic epilepsy-associated gene Kctd7 regulates retinal neurovascular patterning and function. Neurochem Int 2019; 129:104486. [PMID: 31175897 DOI: 10.1016/j.neuint.2019.104486] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 06/04/2019] [Accepted: 06/05/2019] [Indexed: 12/28/2022]
Abstract
Neuron function relies on and instructs the development and precise organization of neurovascular units that in turn support circuit activity. However, our understanding of the molecular cues that regulate this relationship remains sparse. Using a high-throughput screening pipeline, we recently identified several new regulators of vascular patterning. Among these was the potassium channel tetramerization domain-containing protein 7 (KCTD7). Mutations in KCTD7 are associated with progressive myoclonic epilepsy, but how KCTD7 regulates neural development and function remains poorly understood. To begin to identify such mechanisms, we focus on mouse retina, a tractable part of the central nervous system that contains precisely ordered neuron subtypes supported by a trilaminar vascular network. We find that deletion of Kctd7 induces defective patterning of the adult retina vascular network, resulting in increased branching, vessel length, and lacunarity. These alterations reflect early and specific defects in vessel development, as emergence of the superficial and deep vascular layers were delayed. These defects are likely due to a role for Kctd7 in inner retina neurons. Kctd7 is absent from vessels but present in neurons in the inner retina, and its deletion resulted in a corresponding increase in the number of bipolar cells in development and increased vessel branching in adults. These alterations were accompanied by retinal function deficits. Together, these data suggest that neuronal Kctd7 drives growth and patterning of the vasculature and that neurovascular interactions may participate in the pathogenesis of KCTD7-related human diseases.
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Affiliation(s)
- Jonathan Alevy
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, 77030, USA; Huffington Center on Aging, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Courtney A Burger
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, 77030, USA; Huffington Center on Aging, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Nicholas E Albrecht
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, 77030, USA; Huffington Center on Aging, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Danye Jiang
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, 77030, USA; Huffington Center on Aging, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Melanie A Samuel
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, 77030, USA; Huffington Center on Aging, Baylor College of Medicine, Houston, TX, 77030, USA.
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19
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Exome sequencing identifies compound heterozygous KCTD7 mutations in a girl with progressivemyoclonus epilepsy. Clin Chim Acta 2019; 493:87-91. [DOI: 10.1016/j.cca.2019.02.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 02/13/2019] [Accepted: 02/27/2019] [Indexed: 12/31/2022]
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20
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Zastrow DB, Kohler JN, Bonner D, Reuter CM, Fernandez L, Grove ME, Fisk DG, Yang Y, Eng CM, Ward PA, Bick D, Worthey EA, Fisher PG, Ashley EA, Bernstein JA, Wheeler MT. A toolkit for genetics providers in follow-up of patients with non-diagnostic exome sequencing. J Genet Couns 2019; 28:213-228. [PMID: 30964584 PMCID: PMC7385984 DOI: 10.1002/jgc4.1119] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 03/01/2019] [Accepted: 03/04/2019] [Indexed: 12/11/2022]
Abstract
There are approximately 7,000 rare diseases affecting 25-30 million Americans, with 80% estimated to have a genetic basis. This presents a challenge for genetics practitioners to determine appropriate testing, make accurate diagnoses, and conduct up-to-date patient management. Exome sequencing (ES) is a comprehensive diagnostic approach, but only 25%-41% of the patients receive a molecular diagnosis. The remaining three-fifths to three-quarters of patients undergoing ES remain undiagnosed. The Stanford Center for Undiagnosed Diseases (CUD), a clinical site of the Undiagnosed Diseases Network, evaluates patients with undiagnosed and rare diseases using a combination of methods including ES. Frequently these patients have non-diagnostic ES results, but strategic follow-up techniques identify diagnoses in a subset. We present techniques used at the CUD that can be adopted by genetics providers in clinical follow-up of cases where ES is non-diagnostic. Solved case examples illustrate different types of non-diagnostic results and the additional techniques that led to a diagnosis. Frequent approaches include segregation analysis, data reanalysis, genome sequencing, additional variant identification, careful phenotype-disease correlation, confirmatory testing, and case matching. We also discuss prioritization of cases for additional analyses.
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Affiliation(s)
- Diane B Zastrow
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
| | - Jennefer N Kohler
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
| | - Devon Bonner
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
| | - Chloe M Reuter
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
| | - Liliana Fernandez
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
| | - Megan E Grove
- Clinical Genomics Program, Stanford Health Care, Stanford, California
| | - Dianna G Fisk
- Clinical Genomics Program, Stanford Health Care, Stanford, California
| | | | | | | | - David Bick
- HudsonAlpha Institute for Biotechnology, Huntsville, Alabama
| | | | - Paul G Fisher
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
- Department of Neurology, Stanford University School of Medicine, Stanford, California
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California
| | - Euan A Ashley
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
- Clinical Genomics Program, Stanford Health Care, Stanford, California
- Department of Genetics, Stanford University School of Medicine, Stanford, California
- Department of Medicine, Stanford University School of Medicine, Stanford, California
| | - Jonathan A Bernstein
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California
| | - Matthew T Wheeler
- Center for Undiagnosed Diseases, Stanford University, Stanford, California
- Department of Medicine, Stanford University School of Medicine, Stanford, California
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21
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Oh SY, Kim JS, Dieterich M. Update on opsoclonus-myoclonus syndrome in adults. J Neurol 2018; 266:1541-1548. [PMID: 30483882 DOI: 10.1007/s00415-018-9138-7] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/17/2018] [Accepted: 11/21/2018] [Indexed: 01/12/2023]
Abstract
Opsoclonus-myoclonus syndrome in adults is a rare and heterogeneous disorder with the clinical features of opsoclonus, myoclonus, ataxia, and behavioral and sleep disturbances. The pathophysiology is thought to be immunological on the basis of paraneoplastic or infectious etiologies. Immunomodulatory therapies should be performed although the response may be incomplete. A number of autoantibodies have been identified against a variety of antigens, but no diagnostic immunological marker has yet been identified. This review focuses on underlying mechanisms of opsoclonus-myoclonus syndrome, including findings that have been identified recently, and provides an update on the clinical features and treatments of this condition.
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Affiliation(s)
- Sun-Young Oh
- Department of Neurology, Chonbuk National University School of Medicine, 20 Geonji-ro, Deokjin-gu, Jeonju, Chonbuk, 561-712, South Korea.
- Research Institute of Clinical Medicine of Chonbuk National University-Biomedical Research Institute of Chonbuk National University Hospital, Jeonju, South Korea.
| | - Ji-Soo Kim
- Department of Neurology, Seoul National University College of Medicine, Seoul, South Korea
- Department of Neurology, Dizziness Center, Clinical Neuroscience Center, Seoul National University Bundang Hospital, Seongnam, South Korea
| | - Marianne Dieterich
- Department of Neurology, Ludwig-Maximilians-University, Munich, Germany
- German Center for Vertigo and Balance Disorders (IFBLMU), Ludwig-Maximilians University, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
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22
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Metz KA, Teng X, Coppens I, Lamb HM, Wagner BE, Rosenfeld JA, Chen X, Zhang Y, Kim HJ, Meadow ME, Wang TS, Haberlandt ED, Anderson GW, Leshinsky-Silver E, Bi W, Markello TC, Pratt M, Makhseed N, Garnica A, Danylchuk NR, Burrow TA, Jayakar P, McKnight D, Agadi S, Gbedawo H, Stanley C, Alber M, Prehl I, Peariso K, Ong MT, Mordekar SR, Parker MJ, Crooks D, Agrawal PB, Berry GT, Loddenkemper T, Yang Y, Maegawa GHB, Aouacheria A, Markle JG, Wohlschlegel JA, Hartman AL, Hardwick JM. KCTD7 deficiency defines a distinct neurodegenerative disorder with a conserved autophagy-lysosome defect. Ann Neurol 2018; 84:766-780. [PMID: 30295347 DOI: 10.1002/ana.25351] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 08/27/2018] [Accepted: 09/23/2018] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Several small case series identified KCTD7 mutations in patients with a rare autosomal recessive disorder designated progressive myoclonic epilepsy (EPM3) and neuronal ceroid lipofuscinosis (CLN14). Despite the name KCTD (potassium channel tetramerization domain), KCTD protein family members lack predicted channel domains. We sought to translate insight gained from yeast studies to uncover disease mechanisms associated with deficiencies in KCTD7 of unknown function. METHODS Novel KCTD7 variants in new and published patients were assessed for disease causality using genetic analyses, cell-based functional assays of patient fibroblasts and knockout yeast, and electron microscopy of patient samples. RESULTS Patients with KCTD7 mutations can exhibit movement disorders or developmental regression before seizure onset, and are distinguished from similar disorders by an earlier age of onset. Although most published KCTD7 patient variants were excluded from a genome sequence database of normal human variations, most newly identified patient variants are present in this database, potentially challenging disease causality. However, genetic analysis and impaired biochemical interactions with cullin 3 support a causal role for patient KCTD7 variants, suggesting deleterious alleles of KCTD7 and other rare disease variants may be underestimated. Both patient-derived fibroblasts and yeast lacking Whi2 with sequence similarity to KCTD7 have impaired autophagy consistent with brain pathology. INTERPRETATION Biallelic KCTD7 mutations define a neurodegenerative disorder with lipofuscin and lipid droplet accumulation but without defining features of neuronal ceroid lipofuscinosis or lysosomal storage disorders. KCTD7 deficiency appears to cause an underlying autophagy-lysosome defect conserved in yeast, thereby assigning a biological role for KCTD7. Ann Neurol 2018;84:774-788.
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Affiliation(s)
- Kyle A Metz
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD
| | - Xinchen Teng
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD.,Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu Province, People's Republic of China
| | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD
| | - Heather M Lamb
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD
| | - Bart E Wagner
- Histopathology Department, Royal Hallamshire Hospital, Sheffield, United Kingdom
| | - Jill A Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Xianghui Chen
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu Province, People's Republic of China
| | - Yu Zhang
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu Province, People's Republic of China
| | - Hee Jong Kim
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Michael E Meadow
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Tim Sen Wang
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD.,Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Edda D Haberlandt
- Clinical Department of Pediatrics I, Innsbruck Medical University, Innsbruck, Austria.,Department of Child and Youth Health, Hospital of Dornbirn, Dornbirn, Austria
| | - Glenn W Anderson
- Histopathology Department, Great Ormond Street Hospital for Children, London, United Kingdom
| | | | - Weimin Bi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Thomas C Markello
- NIH Undiagnosed Diseases Program, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD
| | - Marsha Pratt
- Department of Pediatrics, University of Oklahoma College of Medicine, Oklahoma City, OK
| | - Nawal Makhseed
- Department of Pediatrics, Jahra Hospital, Ministry of Health, Al Jahra, Kuwait
| | - Adolfo Garnica
- Department of Pediatrics, University of Arkansas for Medical Sciences and Arkansas Children's Hospital, Little Rock, AR
| | - Noelle R Danylchuk
- Department of Pediatrics, University of Arkansas for Medical Sciences and Arkansas Children's Hospital, Little Rock, AR
| | - Thomas A Burrow
- Department of Pediatrics, University of Arkansas for Medical Sciences and Arkansas Children's Hospital, Little Rock, AR
| | - Parul Jayakar
- Division of Genetics and Metabolism, Nicklaus Children's Hospital, Miami, FL
| | | | - Satish Agadi
- Department of Neurology, Texas Children's Hospital, Houston, TX
| | | | | | - Michael Alber
- Pediatric Neurology and Developmental Medicine, University of Tübingen, Tübingen, Germany
| | | | - Katrina Peariso
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
| | - Min Tsui Ong
- Department of Paediatric Neurology, Sheffield Children's National Health Service Foundation Trust, Sheffield, United Kingdom
| | - Santosh R Mordekar
- Department of Paediatric Neurology, Sheffield Children's National Health Service Foundation Trust, Sheffield, United Kingdom
| | - Michael J Parker
- Sheffield Clinical Genetics Service, Sheffield Children's National Health Service Foundation Trust, Sheffield, United Kingdom
| | - Daniel Crooks
- Department of Neuropathology, Walton Centre National Health Service Foundation Trust, Liverpool, United Kingdom
| | - Pankaj B Agrawal
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Gerard T Berry
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, MA
| | | | - Yaping Yang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Gustavo H B Maegawa
- Department of Pediatrics/Genetics and Metabolism, University of Florida, Gainesville, FL
| | - Abdel Aouacheria
- Montpellier Institute of Evolution Sciences, University of Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | - Janet G Markle
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD
| | - James A Wohlschlegel
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Adam L Hartman
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - J Marie Hardwick
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD.,Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD
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23
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Oyrer J, Maljevic S, Scheffer IE, Berkovic SF, Petrou S, Reid CA. Ion Channels in Genetic Epilepsy: From Genes and Mechanisms to Disease-Targeted Therapies. Pharmacol Rev 2018; 70:142-173. [PMID: 29263209 DOI: 10.1124/pr.117.014456] [Citation(s) in RCA: 163] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 10/02/2017] [Indexed: 12/19/2022] Open
Abstract
Epilepsy is a common and serious neurologic disease with a strong genetic component. Genetic studies have identified an increasing collection of disease-causing genes. The impact of these genetic discoveries is wide reaching-from precise diagnosis and classification of syndromes to the discovery and validation of new drug targets and the development of disease-targeted therapeutic strategies. About 25% of genes identified in epilepsy encode ion channels. Much of our understanding of disease mechanisms comes from work focused on this class of protein. In this study, we review the genetic, molecular, and physiologic evidence supporting the pathogenic role of a number of different voltage- and ligand-activated ion channels in genetic epilepsy. We also review proposed disease mechanisms for each ion channel and highlight targeted therapeutic strategies.
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Affiliation(s)
- Julia Oyrer
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Snezana Maljevic
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Ingrid E Scheffer
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Samuel F Berkovic
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Steven Petrou
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Christopher A Reid
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
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24
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Moen MN, Fjær R, Hamdani EH, Laerdahl JK, Menchini RJ, Vigeland MD, Sheng Y, Undlien DE, Hassel B, Salih MA, El Khashab HY, Selmer KK, Chaudhry FA. Pathogenic variants in KCTD7 perturb neuronal K+ fluxes and glutamine transport. Brain 2016; 139:3109-3120. [PMID: 27742667 DOI: 10.1093/brain/aww244] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 06/11/2016] [Accepted: 08/17/2016] [Indexed: 12/11/2022] Open
Abstract
Progressive myoclonus epilepsy is a heterogeneous group of disorders characterized by myoclonic and tonic-clonic seizures, ataxia and cognitive decline. We here present two affected brothers. At 9 months of age the elder brother developed ataxia and myoclonic jerks. In his second year he lost the ability to walk and talk, and he developed drug-resistant progressive myoclonus epilepsy. The cerebrospinal fluid level of glutamate was decreased while glutamine was increased. His younger brother manifested similar symptoms from 6 months of age. By exome sequencing of the proband we identified a novel homozygous frameshift variant in the potassium channel tetramerization domain 7 (KCTD7) gene (NM_153033.1:c.696delT: p.F232fs), which results in a truncated protein. The identified F232fs variant is inherited in an autosomal recessive manner, and the healthy consanguineous parents carry the variant in a heterozygous state. Bioinformatic analyses and structure modelling showed that KCTD7 is a highly conserved protein, structurally similar to KCTD5 and several voltage-gated potassium channels, and that it may form homo- or heteromultimers. By heterologous expression in Xenopus laevis oocytes, we demonstrate that wild-type KCTD7 hyperpolarizes cells in a K+ dependent manner and regulates activity of the neuronal glutamine transporter SAT2 (Slc38a2), while the F232fs variant impairs K+ fluxes and obliterates SAT2-dependent glutamine transport. Characterization of four additional disease-causing variants (R94W, R184C, N273I, Y276C) bolster these results and reveal the molecular mechanisms involved in the pathophysiology of KCTD7-related progressive myoclonus epilepsy. Thus, our data demonstrate that KCTD7 has an impact on K+ fluxes, neurotransmitter synthesis and neuronal function, and that malfunction of the encoded protein may lead to progressive myoclonus epilepsy.
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Affiliation(s)
- Marivi Nabong Moen
- 1 The Institute of Basic Medical Sciences, Department of Molecular Medicine, University of Oslo, Oslo, Norway
| | - Roar Fjær
- 2 Department of Medical Genetics, Oslo University Hospital and University of Oslo, Norway
| | - El Hassan Hamdani
- 1 The Institute of Basic Medical Sciences, Department of Molecular Medicine, University of Oslo, Oslo, Norway.,3 Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
| | - Jon K Laerdahl
- 4 Department of Microbiology, Oslo University Hospital, Oslo, Norway.,5 Bioinformatics Core Facility, Department of Informatics, University of Oslo, Oslo, Norway
| | - Robin Johansen Menchini
- 1 The Institute of Basic Medical Sciences, Department of Molecular Medicine, University of Oslo, Oslo, Norway
| | - Magnus Dehli Vigeland
- 2 Department of Medical Genetics, Oslo University Hospital and University of Oslo, Norway
| | - Ying Sheng
- 2 Department of Medical Genetics, Oslo University Hospital and University of Oslo, Norway
| | - Dag Erik Undlien
- 2 Department of Medical Genetics, Oslo University Hospital and University of Oslo, Norway
| | - Bjørnar Hassel
- 6 Department of Complex Neurology and Neurohabilitation, Oslo University Hospital, Oslo, Norway
| | - Mustafa A Salih
- 7 Division of Paediatric Neurology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Heba Y El Khashab
- 7 Division of Paediatric Neurology, College of Medicine, King Saud University, Riyadh, Saudi Arabia.,8 Department of Paediatrics, Ain Shams University, Cairo, Egypt
| | - Kaja Kristine Selmer
- 2 Department of Medical Genetics, Oslo University Hospital and University of Oslo, Norway.,9 National Centre for Rare Epilepsy-related Disorders, Oslo University Hospital, Oslo, Norway
| | - Farrukh Abbas Chaudhry
- 1 The Institute of Basic Medical Sciences, Department of Molecular Medicine, University of Oslo, Oslo, Norway .,3 Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
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25
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Torres-Vega E, Durán-Moreno M, Sánchez Del Pino M, Yáñez Y, Cañete A, Castel V, López-Cuevas R, Vílchez JJ, Dalmau J, Graus F, García Verdugo JM, Bataller L. Immunoproteomic studies on paediatric opsoclonus-myoclonus associated with neuroblastoma. J Neuroimmunol 2016; 297:98-102. [PMID: 27397082 DOI: 10.1016/j.jneuroim.2016.05.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 05/20/2016] [Accepted: 05/20/2016] [Indexed: 01/29/2023]
Abstract
We aimed to identify new cell-membrane antigens implicated in opsoclonus-myoclonus with neuroblastoma. The sera of 3 out of 14 patients showed IgG electron-microscopy immunogold reactivity on SH-SY5Y neuroblastoma cells. Immunoprecipitation experiments using rat brain synaptosomes and SH-SY5Y cells led to the identification of: (1) thirty-one nuclear/cytoplasmic proteins (including antigens HuB, HuC); (2) seven neuronal membrane proteins, including the Shaw-potassium channel Kv3.3 (KCNC3), whose genetic disruption in mice causes ataxia and generalized muscle twitching. Although cell-based assays did not demonstrate direct antigenicity, our findings point to Shaw-related subfamily of the potassium voltage-gated channels complexed proteins as hypothetical antigenic targets.
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Affiliation(s)
- Estefanía Torres-Vega
- Laboratorio de Neurología, Instituto de Investigación Sanitaria La Fe, Hospital Universitario y Politécnico La Fe, CIBERER, Valencia, Spain
| | - María Durán-Moreno
- Laboratorio de Neurobiología Comparada, Instituto Cavanilles, Universidad de Valencia, CIBERNED, Valencia, Spain
| | | | - Yania Yáñez
- Unidad de Oncología Pediátrica, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Adela Cañete
- Unidad de Oncología Pediátrica, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Victoria Castel
- Unidad de Oncología Pediátrica, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Rogelio López-Cuevas
- Servicio de Neurología, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Juan Jesús Vílchez
- Laboratorio de Neurología, Instituto de Investigación Sanitaria La Fe, Hospital Universitario y Politécnico La Fe, CIBERER, Valencia, Spain; Servicio de Neurología, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Josep Dalmau
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA, and Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain; Laboratori de Neurologia, Institut d'Investigacions Biomèdiques August Pi I Sunyer (IDIBAPS), and Servei de Neurologia, Hospital Clínic, Barcelona, Spain
| | - Francesc Graus
- Laboratori de Neurologia, Institut d'Investigacions Biomèdiques August Pi I Sunyer (IDIBAPS), and Servei de Neurologia, Hospital Clínic, Barcelona, Spain
| | - José Manuel García Verdugo
- Laboratorio de Neurobiología Comparada, Instituto Cavanilles, Universidad de Valencia, CIBERNED, Valencia, Spain
| | - Luis Bataller
- Laboratorio de Neurología, Instituto de Investigación Sanitaria La Fe, Hospital Universitario y Politécnico La Fe, CIBERER, Valencia, Spain; Servicio de Neurología, Hospital Universitario y Politécnico La Fe, Valencia, Spain.
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26
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Berbegall AP, López-Almaraz R, Navarro S, Noguera R. Genetic features of neuroblastic tumors associated with opsoclonus-myoclonus syndrome opens up the possibility for detection in peripheral blood. Expert Rev Neurother 2016; 16:465-7. [PMID: 26949993 DOI: 10.1586/14737175.2016.1163221] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Ana P Berbegall
- a Pathology Department , Medical School, University of Valencia, INCLIVA , Valencia , Spain
| | - Ricardo López-Almaraz
- b Pediatric Oncology and Hematology , Hospital Universitario Cruces , Bilbao , Spain
| | - Samuel Navarro
- a Pathology Department , Medical School, University of Valencia, INCLIVA , Valencia , Spain
| | - Rosa Noguera
- a Pathology Department , Medical School, University of Valencia, INCLIVA , Valencia , Spain
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27
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Drivenes B, Born AP, Ek J, Dunoe M, Uldall PV. A child with myoclonus-dystonia (DYT11) misdiagnosed as atypical opsoclonus myoclonus syndrome. Eur J Paediatr Neurol 2015; 19:719-21. [PMID: 26278497 DOI: 10.1016/j.ejpn.2015.07.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Revised: 06/09/2015] [Accepted: 07/07/2015] [Indexed: 10/23/2022]
Abstract
INTRODUCTION DYT11 is an autosomal dominant inherited movement disorder characterized by myoclonus and dystonia. CLINICAL PRESENTATION We present a case with atypical symptoms and with episodes of ataxia and myoclonus preceded by infections. Atypical presentation of opsoclonus myoclonus syndrome was suspected and treatment with bolus steroids and immunoglobulin were initiated with some response over 28 months. A re-evaluation gave suspicion of a dyskinetic disorder and whole exome-sequencing was performed but no causal variant was identified. OUTCOME A specific analysis of the SGCE gene was subsequently initiated, which revealed a pathogenic aberration confirming the diagnosis of DYT11. CONCLUSION A clinical DYT11 diagnosis can be difficult to establish in early childhood without a known family history.
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Affiliation(s)
- Bergitte Drivenes
- Department of Children and Youth, Hvidovre Hospital, Kettegaard alle 30, 2650 Hvidovre, Denmark.
| | - Alfred Peter Born
- Department of Children and Youth, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen E, Denmark.
| | - Jakob Ek
- Molecular Genetics Laboratory, Dept. of Clinical Genetics, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen E, Denmark.
| | - Morten Dunoe
- Molecular Genetics Laboratory, Dept. of Clinical Genetics, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen E, Denmark.
| | - Peter Vilhelm Uldall
- Department of Children and Youth, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen E, Denmark.
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28
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Mole SE, Cotman SL. Genetics of the neuronal ceroid lipofuscinoses (Batten disease). Biochim Biophys Acta Mol Basis Dis 2015; 1852:2237-41. [PMID: 26026925 DOI: 10.1016/j.bbadis.2015.05.011] [Citation(s) in RCA: 214] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 05/12/2015] [Accepted: 05/18/2015] [Indexed: 11/17/2022]
Abstract
The neuronal ceroid lipofuscinoses (NCLs) are a group of inherited neurodegenerative disorders that affect children and adults and are grouped together by similar clinical features and the accumulation of autofluorescent storage material. More than a dozen genes containing over 430 mutations underlying human NCLs have been identified. These genes encode lysosomal enzymes (CLN1, CLN2, CLN10, CLN13), a soluble lysosomal protein (CLN5), a protein in the secretory pathway (CLN11), two cytoplasmic proteins that also peripherally associate with membranes (CLN4, CLN14), and many transmembrane proteins with different subcellular locations (CLN3, CLN6, CLN7, CLN8, CLN12). For most NCLs, the function of the causative gene has not been fully defined. Most of the mutations in these genes are associated with a typical disease phenotype, but some result in variable disease onset, severity, and progression, including distinct clinical phenotypes. There remain disease subgroups with unknown molecular genetic backgrounds. This article is part of a Special Issue entitled: "Current Research on the Neuronal Ceroid Lipofuscinoses (Batten Disease)."
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Affiliation(s)
- Sara E Mole
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, UK; UCL Institute of Child Health and Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK.
| | - Susan L Cotman
- Center for Human Genetic Research, Department of Neurology, Massachusetts General Hospital, 185 Cambridge Street, Boston, MA 02114, USA
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Farhan SMK, Murphy LM, Robinson JF, Wang J, Siu VM, Rupar CA, Prasad AN, Hegele RA. Linkage analysis and exome sequencing identify a novel mutation inKCTD7in patients with progressive myoclonus epilepsy with ataxia. Epilepsia 2014; 55:e106-11. [DOI: 10.1111/epi.12730] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2014] [Indexed: 02/02/2023]
Affiliation(s)
- Sali M. K. Farhan
- Robarts Research Institute; Schulich School of Medicine and Dentistry; Western University; London Ontario Canada
- Department of Biochemistry; Schulich School of Medicine and Dentistry; Western University; London Ontario Canada
| | - Lisa M. Murphy
- Robarts Research Institute; Schulich School of Medicine and Dentistry; Western University; London Ontario Canada
| | - John F. Robinson
- Robarts Research Institute; Schulich School of Medicine and Dentistry; Western University; London Ontario Canada
| | - Jian Wang
- Robarts Research Institute; Schulich School of Medicine and Dentistry; Western University; London Ontario Canada
| | - Victoria M. Siu
- Department of Biochemistry; Schulich School of Medicine and Dentistry; Western University; London Ontario Canada
- Medical Genetics Program; Department of Pediatrics; London Health Sciences Centre; London Ontario Canada
- Children's Health Research Institute; London Health Sciences Centre; London Ontario Canada
| | - C. Anthony Rupar
- Department of Biochemistry; Schulich School of Medicine and Dentistry; Western University; London Ontario Canada
- Medical Genetics Program; Department of Pediatrics; London Health Sciences Centre; London Ontario Canada
- Children's Health Research Institute; London Health Sciences Centre; London Ontario Canada
| | - Asuri N. Prasad
- Children's Health Research Institute; London Health Sciences Centre; London Ontario Canada
- Division of Clinical Neurological Sciences; Department of Pediatrics; London Health Sciences Centre; London Ontario Canada
| | - Robert A. Hegele
- Robarts Research Institute; Schulich School of Medicine and Dentistry; Western University; London Ontario Canada
- Department of Biochemistry; Schulich School of Medicine and Dentistry; Western University; London Ontario Canada
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30
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Morales-Briceño H, Rodríguez-Violante M, Cervantes-Arriaga A. Simultaneous Presentation of Ocular Flutter in Two Sisters. Mov Disord Clin Pract 2014; 1:265-266. [PMID: 30713865 DOI: 10.1002/mdc3.12064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 05/31/2014] [Accepted: 06/02/2014] [Indexed: 11/07/2022] Open
Affiliation(s)
- Hugo Morales-Briceño
- Department of Neurology Movement Disorders Clinic Hospital de Especialidades Centro Médico Nacional Siglo XXI, IMSS México City México
- Movement Disorders Clinic Instituto Nacional de Neurología y Neurocirugía México City México
| | - Mayela Rodríguez-Violante
- Movement Disorders Clinic Instituto Nacional de Neurología y Neurocirugía México City México
- Clinical Neurodegenerative Disease Research Unit Instituto Nacional de Neurología y Neurocirugía México City México
| | - Amin Cervantes-Arriaga
- Movement Disorders Clinic Instituto Nacional de Neurología y Neurocirugía México City México
- Clinical Neurodegenerative Disease Research Unit Instituto Nacional de Neurología y Neurocirugía México City México
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31
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Singhi P, Sahu JK, Sarkar J, Bansal D. Clinical profile and outcome of children with opsoclonus-myoclonus syndrome. J Child Neurol 2014; 29:58-61. [PMID: 23318697 DOI: 10.1177/0883073812471433] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The opsoclonus-myoclonus syndrome is a distinct disorder characterized by opsoclonus, myoclonus, and ataxia, along with marked irritability and behavioral changes. Worldwide, data on its epidemiology, clinical features, and outcome are scarce. The aim of the study was to determine the clinical profile and outcome of children with this disorder. A retrospective study of all children admitted with a diagnosis of opsoclonus-myoclonus from 2000 to 2012 was done. Outcome was assessed on follow-up by direct assessment and by telephonic interview. Eleven patients with a diagnosis of opsoclonus-myoclonus were admitted over a 12-year period. Of the 11, 4 had paraneoplastic etiology. Children with paraneoplastic opsoclonus had more relapses and a poor outcome as compared to an idiopathic group. Paraneoplastic opsoclonus had a poor outcome in our experience.
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Affiliation(s)
- Pratibha Singhi
- 1Pediatric Neurology Division, Department of Pediatrics, Post-Graduate Institute of Medical Education & Research, Chandigarh, India
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32
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Handel AE, Disanto G, Ramagopalan SV. Next-generation sequencing in understanding complex neurological disease. Expert Rev Neurother 2013; 13:215-27. [PMID: 23368808 DOI: 10.1586/ern.12.165] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Next-generation sequencing techniques have made vast quantities of data on human genomes and transcriptomes available to researchers. Huge progress has been made towards understanding the basis of many Mendelian neurological conditions, but progress has been considerably slower in complex neurological diseases (multiple sclerosis, migraine, Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and so on). The authors review current next-generation sequencing methodologies and present selected studies illustrating how these have been used to cast light on the genetic etiology of complex neurological diseases with specific focus on multiple sclerosis. The authors highlight particular pitfalls in next-generation sequencing experiments and speculate on both clinical and research applications of these sequencing platforms for complex neurological disorders in the future.
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Affiliation(s)
- Adam E Handel
- Department of Physiology, Anatomy and Genetics, University of Oxford, UK
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An unusual clinical severity of 16p11.2 deletion syndrome caused by unmasked recessive mutation of CLN3. Eur J Hum Genet 2013; 22:369-73. [PMID: 23860047 DOI: 10.1038/ejhg.2013.141] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2013] [Revised: 05/29/2013] [Accepted: 06/03/2013] [Indexed: 01/09/2023] Open
Abstract
With the introduction of array comparative genomic hybridization (aCGH) techniques in the diagnostic setting of patients with developmental delay and congenital malformations, many new microdeletion syndromes have been recognized. One of these recently recognized microdeletion syndromes is the 16p11.2 deletion syndrome, associated with variable clinical outcomes including developmental delay, autism spectrum disorder, epilepsy, and obesity, but also apparently normal phenotype. We report on a 16-year-old patient with developmental delay, exhibiting retinis pigmentosa with progressive visual failure from the age of 9 years, ataxia, and peripheral neuropathy. Chromosomal microarray analysis identified a 1.7-Mb 16p11.2 deletion encompassing the 593-kb common deletion (∼29.5 to ∼30.1 Mb; Hg18) and the 220-kb distal deletion (∼28.74 to ∼28.95 Mb; Hg18) that partially included the CLN3 gene. As the patient's clinical findings were different from usual 16p11.2 microdeletion phenotypes and showed some features reminiscent of juvenile neuronal ceroid-lipofuscinosis (JNCL, Batten disease, OMIM 204200), we suspected and confirmed a mutation of the remaining CLN3 allele. This case further illustrates that unmasking of hemizygous recessive mutations by chromosomal deletion represents one explanation for the phenotypic variability observed in chromosomal deletion disorders.
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Genetic basis and phenotypic correlations of the neuronal ceroid lipofusinoses. Biochim Biophys Acta Mol Basis Dis 2013; 1832:1827-30. [PMID: 23542453 DOI: 10.1016/j.bbadis.2013.03.017] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 03/01/2013] [Accepted: 03/15/2013] [Indexed: 12/11/2022]
Abstract
The neuronal ceroid lipofuscinoses (NCLs) are a group of inherited neurodegenerative disorders that mainly affect children and are grouped together by similar clinical features and the accumulation of autofluorescent storage material. More than a dozen genes containing nearly 400 mutations underlying human NCLs have been identified. Most of the mutations in these genes are associated with a typical disease phenotype, but some result in variable disease onset, severity and progression. There are still disease subgroups with unknown molecular genetic backgrounds. This article is part of a Special Issue entitled: The Neuronal Ceroid Lipofuscinoses or Batten Disease.
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