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Zeng Y, Wu T, Liang F, Long S, Guo W, Huang Y, Pei Z. Expression of human Ras-related protein Rab39B variant T168K in Caenorhabditis elegans leads to motor dysfunction and dopaminergic neuron degeneration. Heliyon 2024; 10:e26902. [PMID: 38444482 PMCID: PMC10912484 DOI: 10.1016/j.heliyon.2024.e26902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 02/20/2024] [Accepted: 02/21/2024] [Indexed: 03/07/2024] Open
Abstract
Human RAB39B gene is related to familial early-onset Parkinson disease. In early adulthood, men with the RAB39B c.503C > A (Thr168Lys, p. T168K) mutation develop typical tremor, bradykinesia, and alpha-synuclein accumulation. We investigated the pathological mechanism of RAB39B T168K in a Caenorhabditis elegans model. In early adult C. elegans, RAB39B T168K led to dopaminergic neuron degeneration that presented as disrupted dendrites and blunt neuronal cells. Abnormal dopamine secretion was inferred from a decline in motor function and a positive basal slowing phenotype. Dopamine-associated tests confirmed that synthesis and recycling of dopamine were normal. The RAB39B T168K mutation might impair dopamine vesicular transmission from the presynaptic membrane to the synaptic gap in dopaminergic neurons. The release-dependent feedback mechanism in neurotransmitters regulates the balance of receptor activities. Protein-protein interactions network analysis revealed that RAB39B may also function in lysosomal degradation and autophagy. Impaired disposal of misfolded α-synuclein eventually leads to protein aggregation. Thus, like other members of the Rab family, RAB39B may be involved in vesicular transport associated with dopamine secretion and α-synuclein clearance.
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Affiliation(s)
- Yixuan Zeng
- Department of Neurology, The First Affiliated Hospital of Shenzhen University, Health Science Center, Shenzhen Second People's Hospital, Shenzhen, China
| | - Tengteng Wu
- Department of Neurology, National Key Clinical Department and Key Discipline of Neurology, Guangdong Key Laboratory for Diagnosis and Treatment of Major Neurological Diseases, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Fengyin Liang
- Department of Neurology, National Key Clinical Department and Key Discipline of Neurology, Guangdong Key Laboratory for Diagnosis and Treatment of Major Neurological Diseases, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Simei Long
- Department of Neurology, National Key Clinical Department and Key Discipline of Neurology, Guangdong Key Laboratory for Diagnosis and Treatment of Major Neurological Diseases, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Wenyuan Guo
- Department of Neurology, National Key Clinical Department and Key Discipline of Neurology, Guangdong Key Laboratory for Diagnosis and Treatment of Major Neurological Diseases, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yi Huang
- Department of Neurology, National Key Clinical Department and Key Discipline of Neurology, Guangdong Key Laboratory for Diagnosis and Treatment of Major Neurological Diseases, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Zhong Pei
- Department of Neurology, National Key Clinical Department and Key Discipline of Neurology, Guangdong Key Laboratory for Diagnosis and Treatment of Major Neurological Diseases, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
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Allison K, Maletic-Savatic M, Pehlivan D. MECP2-related disorders while gene-based therapies are on the horizon. Front Genet 2024; 15:1332469. [PMID: 38410154 PMCID: PMC10895005 DOI: 10.3389/fgene.2024.1332469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 01/23/2024] [Indexed: 02/28/2024] Open
Abstract
The emergence of new genetic tools has led to the discovery of the genetic bases of many intellectual and developmental disabilities. This creates exciting opportunities for research and treatment development, and a few genetic disorders (e.g., spinal muscular atrophy) have recently been treated with gene-based therapies. MECP2 is found on the X chromosome and regulates the transcription of thousands of genes. Loss of MECP2 gene product leads to Rett Syndrome, a disease found primarily in females, and is characterized by developmental regression, motor dysfunction, midline hand stereotypies, autonomic nervous system dysfunction, epilepsy, scoliosis, and autistic-like behavior. Duplication of MECP2 causes MECP2 Duplication Syndrome (MDS). MDS is found mostly in males and presents with developmental delay, hypotonia, autistic features, refractory epilepsy, and recurrent respiratory infections. While these two disorders share several characteristics, their differences (e.g., affected sex, age of onset, genotype/phenotype correlations) are important to distinguish in the light of gene-based therapy because they require opposite solutions. This review explores the clinical features of both disorders and highlights these important clinical differences.
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Affiliation(s)
- Katherine Allison
- Royal College of Surgeons in Ireland, School of Medicine, Dublin, Ireland
| | - Mirjana Maletic-Savatic
- Section of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, United States
| | - Davut Pehlivan
- Section of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX, United States
- Blue Bird Circle Rett Center, Texas Children's Hospital, Houston, TX, United States
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Xing XH, Takam R, Bao XY, Ba-alwi NA, Ji H. Methyl-CpG-Binding protein 2 duplication syndrome in a Chinese patient: A case report and review of the literature. World J Clin Cases 2023; 11:6505-6514. [PMID: 37900250 PMCID: PMC10600989 DOI: 10.12998/wjcc.v11.i27.6505] [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: 05/07/2023] [Revised: 08/08/2023] [Accepted: 08/29/2023] [Indexed: 09/20/2023] Open
Abstract
BACKGROUND Chromosomal Xq28 region duplication encompassing methyl-CpG-binding protein 2 (MECP2) results in an identifiable phenotype and global developmental delay known as MECP2 duplication syndrome (MDS). This syndrome has a wide range of clinical manifestations, including abnormalities in appearance, neurodevelopment, and gastrointestinal motility; recurrent infections; and spasticity. Here, we report a case of confirmed MDS at our institution. CASE SUMMARY A 12-year-old Chinese boy presented with intellectual disability (poor intellectual [reasoning, judgment, abstract thinking, and learning] and adaptive [lack of communication and absent social skills, apraxia, and ataxia] functioning) and dysmorphism. He had no history of recurrent infections, seizures, or bowel dysfunction, which is different from that in reported cases. Microarray comparative genomic hybridization confirmed MECP2 duplication in the patient and his mother who is a carrier. The duplication size was the same in the patient and his mother. No prophylactic antibiotic or anti-seizure therapy was offered to the patient or his mother before or after the consultation. CONCLUSION MDS is rare and has various clinical presentations. Clinical suspicion is critical in patients presenting with developmental delays.
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Affiliation(s)
- Xu-Hang Xing
- Department of Pediatrics, The First Part of The First Affiliated Hospital of Dalian Medical University, Dalian 116011, Liaoning Province, China
| | - Russel Takam
- Department of Pediatrics, The First Part of The First Affiliated Hospital of Dalian Medical University, Dalian 116011, Liaoning Province, China
| | - Xiu-Ying Bao
- Department of Pediatrics, The First Part of The First Affiliated Hospital of Dalian Medical University, Dalian 116011, Liaoning Province, China
| | - Nour Abdallah Ba-alwi
- Department of Pediatrics, The First Part of The First Affiliated Hospital of Dalian Medical University, Dalian 116011, Liaoning Province, China
| | - Hong Ji
- Department of Pediatrics, The First Part of The First Affiliated Hospital of Dalian Medical University, Dalian 116011, Liaoning Province, China
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Wang Z, Niu M, Zheng N, Meng J, Jiang Y, Yang D, Yao P, Yao T, Luo H, Xu H, Ge Y, Zhang YW, Zhang X. Increased level of RAB39B leads to neuronal dysfunction and behavioural changes in mice. J Cell Mol Med 2023; 27:1214-1226. [PMID: 36977207 PMCID: PMC10148058 DOI: 10.1111/jcmm.17704] [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: 03/31/2022] [Revised: 01/22/2023] [Accepted: 02/22/2023] [Indexed: 03/30/2023] Open
Abstract
Duplications of the Xq28 region are a common cause of X-linked intellectual disability (XLID). The RAB39B gene locates in Xq28 and has been implicated in disease pathogenesis. However, whether increased dosage of RAB39B leads to cognitive impairment and synaptic dysfunction remains elusive. Herein, we overexpressed RAB39B in mouse brain by injecting AAVs into bilateral ventricles of neonatal animals. We found that at 2 months of age, neuronal overexpression of RAB39B impaired the recognition memory and the short-term working memory in mice and resulted in certain autism-like behaviours, including social novelty defect and repetitive grooming behaviour in female mice. Moreover, overexpression of RAB39B decreased dendritic arborization of primary neurons in vitro and reduced synaptic transmission in female mice. Neuronal overexpression of RAB39B also altered autophagy without affecting levels and PSD distribution of synaptic proteins. Our results demonstrate that overexpression of RAB39B compromises normal neuronal development, thereby resulting in dysfunctional synaptic transmission and certain intellectual disability and behavioural abnormalities in mice. These findings identify a molecular mechanism underlying XLID with increased copy numbers of Xq28 and provide potential strategies for disease intervention.
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Affiliation(s)
- Zijie Wang
- Center for Brain Sciences, the First Affiliated Hospital of Xiamen University, Institute of Neuroscience, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, School of Medicine, Xiamen University, Xiamen, China
- Department of Neurosurgery, Xiang'an Hospital of Xiamen University, Xiamen, China
| | - Mengxi Niu
- Center for Brain Sciences, the First Affiliated Hospital of Xiamen University, Institute of Neuroscience, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, School of Medicine, Xiamen University, Xiamen, China
| | - Naizhen Zheng
- Center for Brain Sciences, the First Affiliated Hospital of Xiamen University, Institute of Neuroscience, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, School of Medicine, Xiamen University, Xiamen, China
| | - Jian Meng
- Center for Brain Sciences, the First Affiliated Hospital of Xiamen University, Institute of Neuroscience, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, School of Medicine, Xiamen University, Xiamen, China
| | - Yiru Jiang
- Center for Brain Sciences, the First Affiliated Hospital of Xiamen University, Institute of Neuroscience, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, School of Medicine, Xiamen University, Xiamen, China
| | - Dingting Yang
- Center for Brain Sciences, the First Affiliated Hospital of Xiamen University, Institute of Neuroscience, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, School of Medicine, Xiamen University, Xiamen, China
| | - Peijie Yao
- Center for Brain Sciences, the First Affiliated Hospital of Xiamen University, Institute of Neuroscience, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, School of Medicine, Xiamen University, Xiamen, China
| | - Tingting Yao
- Center for Brain Sciences, the First Affiliated Hospital of Xiamen University, Institute of Neuroscience, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, School of Medicine, Xiamen University, Xiamen, China
| | - Hong Luo
- Center for Brain Sciences, the First Affiliated Hospital of Xiamen University, Institute of Neuroscience, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, School of Medicine, Xiamen University, Xiamen, China
| | - Huaxi Xu
- Center for Brain Sciences, the First Affiliated Hospital of Xiamen University, Institute of Neuroscience, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, School of Medicine, Xiamen University, Xiamen, China
| | - Yunlong Ge
- Department of Neurosurgery, Xiang'an Hospital of Xiamen University, Xiamen, China
| | - Yun-Wu Zhang
- Center for Brain Sciences, the First Affiliated Hospital of Xiamen University, Institute of Neuroscience, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, School of Medicine, Xiamen University, Xiamen, China
| | - Xian Zhang
- Center for Brain Sciences, the First Affiliated Hospital of Xiamen University, Institute of Neuroscience, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, School of Medicine, Xiamen University, Xiamen, China
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5
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Yahya V, Di Fonzo A, Monfrini E. Genetic Evidence for Endolysosomal Dysfunction in Parkinson’s Disease: A Critical Overview. Int J Mol Sci 2023; 24:ijms24076338. [PMID: 37047309 PMCID: PMC10094484 DOI: 10.3390/ijms24076338] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 03/23/2023] [Accepted: 03/26/2023] [Indexed: 03/30/2023] Open
Abstract
Parkinson’s disease (PD) is the second most common neurodegenerative disorder in the aging population, and no disease-modifying therapy has been approved to date. The pathogenesis of PD has been related to many dysfunctional cellular mechanisms, however, most of its monogenic forms are caused by pathogenic variants in genes involved in endolysosomal function (LRRK2, VPS35, VPS13C, and ATP13A2) and synaptic vesicle trafficking (SNCA, RAB39B, SYNJ1, and DNAJC6). Moreover, an extensive search for PD risk variants revealed strong risk variants in several lysosomal genes (e.g., GBA1, SMPD1, TMEM175, and SCARB2) highlighting the key role of lysosomal dysfunction in PD pathogenesis. Furthermore, large genetic studies revealed that PD status is associated with the overall “lysosomal genetic burden”, namely the cumulative effect of strong and weak risk variants affecting lysosomal genes. In this context, understanding the complex mechanisms of impaired vesicular trafficking and dysfunctional endolysosomes in dopaminergic neurons of PD patients is a fundamental step to identifying precise therapeutic targets and developing effective drugs to modify the neurodegenerative process in PD.
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Affiliation(s)
- Vidal Yahya
- Dino Ferrari Center, Department of Pathophysiology and Transplantation, University of Milan, 20122 Milan, Italy;
- Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Neurology Unit, 20122 Milan, Italy;
| | - Alessio Di Fonzo
- Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Neurology Unit, 20122 Milan, Italy;
| | - Edoardo Monfrini
- Dino Ferrari Center, Department of Pathophysiology and Transplantation, University of Milan, 20122 Milan, Italy;
- Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Neurology Unit, 20122 Milan, Italy;
- Correspondence:
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Akahoshi K, Nakagawa E, Goto YI, Inoue K. Duplication within two regions distal to MECP2: clinical similarity with MECP2 duplication syndrome. BMC Med Genomics 2023; 16:43. [PMID: 36879246 PMCID: PMC9987063 DOI: 10.1186/s12920-023-01465-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 02/21/2023] [Indexed: 03/08/2023] Open
Abstract
BACKGROUND X-linked methyl-CpG-binding protein 2 (MECP2) duplication syndrome is prevalent in approximately 1% of X-linked intellectual disabilities. Accumulating evidence has suggested that MECP2 is the causative gene of MECP2 duplication syndrome. We report a case of a 17-year-old boy with a 1.2 Mb duplication distal to MECP2 on chromosome Xq28. Although this region does not contain MECP2, the clinical features and course of the boy are remarkably similar to those observed in MECP2 duplication syndrome. Recently, case reports have described duplication in the region distal to, and not containing, MECP2. These regions have been classified as the K/L-mediated Xq28 duplication region and int22h1/int22h2-mediated Xq28 duplication region. The case reports also described signs similar to those of MECP2 duplication syndrome. To the best of our knowledge, ours is the first case to include these two regions. CASE PRESENTATION The boy presented with a mild to moderate regressive intellectual disability and progressive neurological disorder. He developed epilepsy at the age of 6 years and underwent a bilateral equinus foot surgery at 14 years of age because of the increasing spasticity in lower extremities since the age of 11. Intracranial findings showed hypoplasia of the corpus callosum, cerebellum, and brain stem; linear hyperintensity in the deep white matter; and decreased white matter capacity. During his childhood, he suffered from recurrent infection. However, genital problems, skin abnormalities and gastrointestinal manifestations (gastroesophageal reflux) were not observed. CONCLUSIONS Cases in which duplication was observed in the region of Xq28 that does not include MECP2 also showed symptoms similar to those of MECP2 duplication syndrome. We compared four pathologies: MECP2 duplication syndrome with minimal regions, duplication within the two distal regions without MECP2, and our case including both regions. Our results suggest that MECP2 alone may not explain all symptoms of duplication in the distal part of Xq28.
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Affiliation(s)
- Keiko Akahoshi
- Department of Pediatrics, Tokyo Children's Rehabilitation Hospital, 4-10-1 Gakuen, Musashi-Murayama, Tokyo, 208-0011, Japan.
| | - Eiji Nakagawa
- Department of Child Neurology, National Center of Neurology and Psychiatry, Tokyo, 187-8551, Japan
| | - Yu-Ichi Goto
- Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, Tokyo, 187-8502, Japan.,Medical Genome Center, National Center of Neurology and Psychiatry, Tokyo, 187-8551, Japan
| | - Ken Inoue
- Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, Tokyo, 187-8502, Japan
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Leffler M, Christie L, Hackett A, Bennetts B, Goel H, Amor DJ, Peters GB, Field M, Dudding-Byth T. Further delineation of dosage-sensitive K/L mediated Xq28 duplication syndrome includes incomplete penetrance. Clin Genet 2023; 103:681-687. [PMID: 36688272 DOI: 10.1111/cge.14303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 01/07/2023] [Accepted: 01/17/2023] [Indexed: 01/24/2023]
Abstract
The low copy tandem repeat area at Xq28 is prone to recurrent copy number gains, including the K/L mediated duplications of 300 kb size (herein described as the K/L mediated Xq28 duplication syndrome). We describe five families, including nine males with K/L mediated Xq28 duplications, some with regions of greater copy number variation (CNV). We summarise findings in 25 affected males reported to date. Within the five families, males were variably affected by seizures, intellectual disability, and neurological features; however, one male with a familial K/L mediated Xq28 duplication has normal intelligence, suggesting that this CNV is not 100% penetrant. Including our five families, 13 carrier females have been identified, with nine presenting phenotypically normal. Three carrier females reported mild learning difficulties, and all of them had duplications containing regions with at least four copies. Delineation of the spectrum of K/L mediated Xq28 duplication syndrome highlights GDI1 as the most likely candidate gene contributing to the phenotype. For patients identified with CNVs in this region, high-resolution microarray is required to define copy number gains and provide families with accurate information.
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Affiliation(s)
- Melanie Leffler
- NSW Genetics of Learning Disability (GOLD) Service, Hunter New England Local Health District, Waratah, New South Wales, Australia
| | - Louise Christie
- NSW Genetics of Learning Disability (GOLD) Service, Hunter New England Local Health District, Waratah, New South Wales, Australia
| | - Anna Hackett
- NSW Genetics of Learning Disability (GOLD) Service, Hunter New England Local Health District, Waratah, New South Wales, Australia
| | - Bruce Bennetts
- Department of Molecular Genetics, Sydney Genome Diagnostics, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Specialty of Genomic Medicine, Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | - Himanshu Goel
- Hunter Genetics, Hunter New England Local Health District, Waratah, New South Wales, Australia.,University of Newcastle, Callaghan, New South Wales, Australia
| | - David J Amor
- Murdoch Children's Research Institute, Parkville, Victoria, Australia.,Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria, Australia.,Department of Paediatrics, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Greg B Peters
- Formerly of Sydney Genome Diagnostics, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Michael Field
- NSW Genetics of Learning Disability (GOLD) Service, Hunter New England Local Health District, Waratah, New South Wales, Australia
| | - Tracy Dudding-Byth
- NSW Genetics of Learning Disability (GOLD) Service, Hunter New England Local Health District, Waratah, New South Wales, Australia.,Hunter Genetics, Hunter New England Local Health District, Waratah, New South Wales, Australia.,University of Newcastle, Callaghan, New South Wales, Australia
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Angelopoulou E, Bougea A, Papageorgiou SG, Villa C. Psychosis in Parkinson's Disease: A Lesson from Genetics. Genes (Basel) 2022; 13:genes13061099. [PMID: 35741861 PMCID: PMC9222985 DOI: 10.3390/genes13061099] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/17/2022] [Accepted: 06/18/2022] [Indexed: 02/06/2023] Open
Abstract
Psychosis in Parkinson's disease (PDP) represents a common and debilitating condition that complicates Parkinson's disease (PD), mainly in the later stages. The spectrum of psychotic symptoms are heterogeneous, ranging from minor phenomena of mild illusions, passage hallucinations and sense of presence to severe psychosis consisting of visual hallucinations (and rarely, auditory and tactile or gustatory) and paranoid delusions. PDP is associated with increased caregiver stress, poorer quality of life for patients and carers, reduced survival and risk of institutionalization with a significant burden on the healthcare system. Although several risk factors for PDP development have been identified, such as aging, sleep disturbances, long history of PD, cognitive impairment, depression and visual disorders, the pathophysiology of psychosis in PD is complex and still insufficiently clarified. Additionally, several drugs used to treat PD can aggravate or even precipitate PDP. Herein, we reviewed and critically analyzed recent studies exploring the genetic architecture of psychosis in PD in order to further understand the pathophysiology of PDP, the risk factors as well as the most suitable therapeutic strategies.
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Affiliation(s)
- Efthalia Angelopoulou
- Department of Neurology, Eginition University Hospital, National and Kapodistrian University of Athens, 11528 Athens, Greece; (E.A.); (A.B.); (S.G.P.)
| | - Anastasia Bougea
- Department of Neurology, Eginition University Hospital, National and Kapodistrian University of Athens, 11528 Athens, Greece; (E.A.); (A.B.); (S.G.P.)
| | - Sokratis G. Papageorgiou
- Department of Neurology, Eginition University Hospital, National and Kapodistrian University of Athens, 11528 Athens, Greece; (E.A.); (A.B.); (S.G.P.)
| | - Chiara Villa
- School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy
- Correspondence: ; Tel.: +39-02-6448-8138
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Chien YC, Chen JS, Shiao YM, Hsiao CH. Prenatal diagnosis of de novo int22h1/int22h2-mediated Xq28 duplication syndrome involving RAB39B following a previous ambiguous genitalia pregnancy. Taiwan J Obstet Gynecol 2022; 61:501-503. [PMID: 35595445 DOI: 10.1016/j.tjog.2022.03.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/26/2021] [Indexed: 11/26/2022] Open
Abstract
OBJECTIVE To report a prenatal diagnosis of int22h1/int22h2-mediated Xq28 duplication syndrome. CASE REPORT Herein, we present the case of a 28-year-old female who had a previous ambiguous genitalia pregnancy without genetic abnormality that was terminated at 23+2 weeks of gestation. The fetus of the current pregnancy harbored a de novo copy number variation at the Xq recurrent region (int22h1/int22h2-flanked; including the RAB39B gene) with a 0.397 Mb microduplication. The literature suggests the clinical manifestation of int22h1/int22h2-mediated Xq28 duplication syndrome tends to show a milder clinical phenotype in females than males. Although the fetus in this case was female, taking into consideration the parents' age and culture, the family decided to terminate this pregnancy due to the genetic abnormality. CONCLUSION Prenatally diagnosed de novo int22h-1/int22h-2-mediated Xq28 duplication syndrome exhibits variable phenotypic traits in female fetuses.
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Affiliation(s)
- Yung Chen Chien
- Department of Medical Education, Taipei Medical University Hospital, Taiwan
| | - Jia Shing Chen
- School of Medicine for International Students, I-Shou University, Kaohsiung, Taiwan
| | - Yu Ming Shiao
- Department of Bioscience Technology, Chung Yuan Christian University, Taiwan
| | - Ching Hua Hsiao
- Department of Obstetrics and Gynecology, Taipei City Hospital, Women and Children Campus, Taiwan; Department of Biomedical Engineering, National Yang Ming Chiao Tung University, Yang Ming Campus, Taiwan.
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Bastos PAD, Barbosa R. A Newly Identified Int22h1/Int22h2‐Mediated Xq28 Duplication Syndrome Case Misdiagnosed as Cerebral Palsy. JOURNAL OF PEDIATRIC NEUROLOGY 2022. [DOI: 10.1055/s-0042-1743435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
AbstractCerebral palsy (CP) is a nonprogressive, early-onset neurodevelopmental disorder affecting ∼2 to 3/1,000 children worldwide. It is characterized by movement/postural disabilities accompanied by sensitive, perceptual, cognitive, communicational, behavioral, and musculoskeletal perturbations. Many CP patients are thought to have genetic etiologies overlapping those of other neurodevelopmental conditions. Herein, we reported a newly discovered case (the 36th case to date) of a female patient (misdiagnosed with CP until age 19) with the rare X-linked intellectual disability syndrome resulting from an int22h1/int22h2-mediated Xq28 duplication. A microarray analysis revealed a ∼0.4 Mb duplication within the 154.1 to 154.6 Mb subregion of Xq28 (hg19, CRCh37), confirming a diagnosis of the rare int22h1/int22h2-mediated Xq28 duplication intellectual disability syndrome. Atypical T2 hyperintensities were also observed. This case report builds upon the limited cohort of X-linked intellectual disability syndrome patients and reiterates the growing observations pertaining to the phenotypic overlap between genetic CP cases and other neurodevelopmental disorders.
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Affiliation(s)
- Paulo André Dias Bastos
- Chronic Diseases Research Centre, NOVA Medical School, Faculty of Medical Sciences, Universidade Nova de Lisboa, Lisbon, Portugal
- Department of Neurology, Hospital de Egas Moniz, Centro Hospitalar de Lisboa Ocidental, Lisbon, Portugal
| | - Raquel Barbosa
- Chronic Diseases Research Centre, NOVA Medical School, Faculty of Medical Sciences, Universidade Nova de Lisboa, Lisbon, Portugal
- Department of Neurology, Hospital de Egas Moniz, Centro Hospitalar de Lisboa Ocidental, Lisbon, Portugal
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11
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Collins BE, Neul JL. Rett Syndrome and MECP2 Duplication Syndrome: Disorders of MeCP2 Dosage. Neuropsychiatr Dis Treat 2022; 18:2813-2835. [PMID: 36471747 PMCID: PMC9719276 DOI: 10.2147/ndt.s371483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 11/14/2022] [Indexed: 11/30/2022] Open
Abstract
Rett syndrome (RTT) is a neurodevelopmental disorder caused predominantly by loss-of-function mutations in the gene Methyl-CpG-binding protein 2 (MECP2), which encodes the MeCP2 protein. RTT is a MECP2-related disorder, along with MECP2 duplication syndrome (MDS), caused by gain-of-function duplications of MECP2. Nearly two decades of research have advanced our knowledge of MeCP2 function in health and disease. The following review will discuss MeCP2 protein function and its dysregulation in the MECP2-related disorders RTT and MDS. This will include a discussion of the genetic underpinnings of these disorders, specifically how sporadic X-chromosome mutations arise and manifest in specific populations. We will then review current diagnostic guidelines and clinical manifestations of RTT and MDS. Next, we will delve into MeCP2 biology, describing the dual landscapes of methylated DNA and its reader MeCP2 across the neuronal genome as well as the function of MeCP2 as a transcriptional modulator. Following this, we will outline common MECP2 mutations and genotype-phenotype correlations in both diseases, with particular focus on mutations associated with relatively mild disease in RTT. We will also summarize decades of disease modeling and resulting molecular, synaptic, and behavioral phenotypes associated with RTT and MDS. Finally, we list several therapeutics in the development pipeline for RTT and MDS and available evidence of their safety and efficacy.
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Affiliation(s)
- Bridget E Collins
- Medical Scientist Training Program, Vanderbilt University, Nashville, TN, USA
| | - Jeffrey L Neul
- Vanderbilt Kennedy Center, Departments of Pediatrics, Pharmacology, and Special Education, Vanderbilt University Medical Center and Vanderbilt University, Nashville, TN, USA
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12
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Mignogna ML, Ficarella R, Gelmini S, Marzulli L, Ponzi E, Gabellone A, Peschechera A, Alessio M, Margari L, Gentile M, D'Adamo P. Clinical characterization of a novel RAB39B nonstop mutation in a family with ASD and severe ID causing RAB39B downregulation and study of a Rab39b knock down mouse model. Hum Mol Genet 2021; 31:1389-1406. [PMID: 34761259 PMCID: PMC9071400 DOI: 10.1093/hmg/ddab320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 11/18/2022] Open
Abstract
Autism spectrum disorder (ASD) and intellectual disability (ID) often exist together in patients. The RAB39B gene has been reported to be mutated in ID patients with additional clinical features ranging from ASD, macrocephaly, seizures and/or early-onset parkinsonism. Here, we describe a novel RAB39B nonstop mutation [Xq28; c.640 T > C; p.(*214Glnext*21)] in a family with ASD, severe ID and poor motor coordination, and we assessed the pathogenicity of the mutation. A heterologous cell system and a Rab39b knockdown (KD) murine model, which mimic the nonstop mutation, were used to validate the deleterious effect of the RAB39B mutation. The mutation led to RAB39B protein instability, resulting in its increased degradation and consequent downregulation. Using a Rab39b KD mouse model, we demonstrated that the downregulation of RAB39B led to increased GluA2 lacking Ca2+-permeable AMPAR composition at the hippocampal neuronal surface and increased dendritic spine density that remained in an immature filopodia-like state. These phenotypes affected behavioural performance in a disease-specific manner. Rab39b KD mice revealed impaired social behaviour but intact social recognition. They also showed normal anxiety-like, exploratory and motivational behaviours but impaired working and associative memories. In conclusion, we found a novel RAB39B nonstop variant that segregated in a family with a clinical phenotype including ID, ASD and poor motor coordination. The pathogenicity of mutations causing the downregulation of RAB39B proteins, impacting AMPAR trafficking and dendritic spine morphogenesis, reinforced the idea that AMPAR modulation and dendritic spine assets could be considered hallmarks of neurodevelopmental disorders.
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Affiliation(s)
- Maria Lidia Mignogna
- Molecular genetics of intellectual disability, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Romina Ficarella
- Medical Genetics Unit, Department of Reproductive Medicine, ASL Bari, Bari, Italy
| | - Susanna Gelmini
- Molecular genetics of intellectual disability, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Lucia Marzulli
- Child Neuropsychiatry Unit, Department of Biomedical Sciences and Human Oncology, University of Bari "Aldo Moro"
| | - Emanuela Ponzi
- Medical Genetics Unit, Department of Reproductive Medicine, ASL Bari, Bari, Italy
| | - Alessandra Gabellone
- Child Neuropsychiatry Unit, Department of Biomedical Sciences and Human Oncology, University of Bari "Aldo Moro"
| | - Antonia Peschechera
- Child Neuropsychiatry Unit, Department of Biomedical Sciences and Human Oncology, University of Bari "Aldo Moro"
| | - Massino Alessio
- Proteome Biochemistry, Center for Omics Sciences, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Lucia Margari
- Child Neuropsychiatry Unit, Department of Biomedical Sciences and Human Oncology, University of Bari "Aldo Moro"
| | - Mattia Gentile
- Medical Genetics Unit, Department of Reproductive Medicine, ASL Bari, Bari, Italy
| | - Patrizia D'Adamo
- Molecular genetics of intellectual disability, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
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13
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Di Lazzaro G, Magrinelli F, Estevez-Fraga C, Valente EM, Pisani A, Bhatia KP. X-Linked Parkinsonism: Phenotypic and Genetic Heterogeneity. Mov Disord 2021; 36:1511-1525. [PMID: 33960519 DOI: 10.1002/mds.28565] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 02/23/2021] [Accepted: 02/26/2021] [Indexed: 02/06/2023] Open
Abstract
X-linked parkinsonism encompasses rare heterogeneous disorders mainly inherited as a recessive trait, therefore being more prevalent in males. Recent developments have revealed a complex underlying panorama, including a spectrum of disorders in which parkinsonism is variably associated with additional neurological and non-neurological signs. In particular, a childhood-onset encephalopathy with epilepsy and/or cognitive disability is the most common feature. Their genetic basis is also heterogeneous, with many causative genes and different mutation types ranging from "classical" coding variants to intronic repeat expansions. In this review, we provide an updated overview of the phenotypic and genetic spectrum of the most relevant X-linked parkinsonian syndromes, namely X-linked dystonia-parkinsonism (XDP, Lubag disease), fragile X-associated tremor/ataxia syndrome (FXTAS), beta-propeller protein-associated neurodegeneration (BPAN, NBIA/PARK-WDR45), Fabry disease, Waisman syndrome, methyl CpG-binding protein 2 (MeCP2) spectrum disorder, phosphoglycerate kinase-1 deficiency syndrome (PGK1) and X-linked parkinsonism and spasticity (XPDS). All clinical and radiological features reported in the literature have been reviewed. Epilepsy occasionally represents the symptom of onset, predating parkinsonism even by a few years; action tremor is another common feature along with akinetic-rigid parkinsonism. A focus on the genetic background and its pathophysiological implications is provided. The pathogenesis of these disorders ranges from well-defined metabolic alterations (PGK1) to non-specific lysosomal dysfunctions (XPDS) and vesicular trafficking alterations (Waisman syndrome). However, in other cases it still remains poorly defined. Recognition of the phenotypic and genetic heterogeneity of X-linked parkinsonism has important implications for diagnosis, management, and genetic counseling. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Giulia Di Lazzaro
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
- Department of Systems Medicine, Tor Vergata University of Rome, Rome, Italy
| | - Francesca Magrinelli
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Carlos Estevez-Fraga
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Enza M Valente
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
- IRCCS Mondino Foundation, Pavia, Italy
| | - Antonio Pisani
- IRCCS Mondino Foundation, Pavia, Italy
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
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14
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The int22h1/int22h2-Mediated Xq28 Duplication Syndrome: An Intersection between Neurodevelopment, Immunology, and Cancer. Genes (Basel) 2021; 12:genes12060860. [PMID: 34199727 PMCID: PMC8229372 DOI: 10.3390/genes12060860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/30/2021] [Accepted: 06/02/2021] [Indexed: 11/23/2022] Open
Abstract
The int22h1/int22h2-mediated Xq28 duplication syndrome is a rare X-linked intellectual disability syndrome (XLIDS) arising from a duplication of the segment between intron 22 homologous regions 1 and 2, on the q28 subregion of the X chromosome. The main clinical features of the syndrome include intellectual disability, neurobehavioral abnormalities, and dysmorphic facial features. Due to the X-linked nature of the syndrome, affected males exhibit more severe phenotypes compared with heterozygous females. A unique distinguishing feature of the syndrome across the sexes, however, is a peculiar combination of recurrent sinopulmonary infections and atopy exclusively seen in a subset of affected males. In addition to the ‘typical’ 0.5 Mb duplication detected in most cases reported to date with the syndrome, a shortened centromeric version, and another 0.2 Mb telomerically shifted one, have been recently identified, with most detected duplications being maternally inherited, except for three recent cases found to have de novo duplications. Interestingly, a recently reported case of an affected male suggests a possible association of the syndrome with multiple malignancies, an observation that has been recently replicated in two pediatric patients. As a result, a better understanding of the pathogenesis of int22h1/int22h2-mediated Xq28 duplication syndrome may grant us a better understanding of the sex-specific differences in immunological responses, as well as the potential role of the genes involved by the duplication, in oncogenesis.
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15
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Koss DJ, Campesan S, Giorgini F, Outeiro TF. Dysfunction of RAB39B-Mediated Vesicular Trafficking in Lewy Body Diseases. Mov Disord 2021; 36:1744-1758. [PMID: 33939203 DOI: 10.1002/mds.28605] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 03/09/2021] [Accepted: 03/12/2021] [Indexed: 12/16/2022] Open
Abstract
Intracellular vesicular trafficking is essential for neuronal development, function, and homeostasis and serves to process, direct, and sort proteins, lipids, and other cargo throughout the cell. This intricate system of membrane trafficking between different compartments is tightly orchestrated by Ras analog in brain (RAB) GTPases and their effectors. Of the 66 members of the RAB family in humans, many have been implicated in neurodegenerative diseases and impairment of their functions contributes to cellular stress, protein aggregation, and death. Critically, RAB39B loss-of-function mutations are known to be associated with X-linked intellectual disability and with rare early-onset Parkinson's disease. Moreover, recent studies have highlighted altered RAB39B expression in idiopathic cases of several Lewy body diseases (LBDs). This review contextualizes the role of RAB proteins in LBDs and highlights the consequences of RAB39B impairment in terms of endosomal trafficking, neurite outgrowth, synaptic maturation, autophagy, as well as alpha-synuclein homeostasis. Additionally, the potential for therapeutic intervention is examined via a discussion of the recent progress towards the development of specific RAB modulators. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- David J Koss
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Susanna Campesan
- Department of Genetics and Genome Biology, University of Leicester, University Road, Leicester, UK
| | - Flaviano Giorgini
- Department of Genetics and Genome Biology, University of Leicester, University Road, Leicester, UK
| | - Tiago F Outeiro
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.,Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Goettingen, Goettingen, Germany.,Max Planck Institute for Experimental Medicine, Goettingen, Germany.,Scientific employee with a honorary contract at Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Göttingen, Germany
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16
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Smith SM, Douaud G, Chen W, Hanayik T, Alfaro-Almagro F, Sharp K, Elliott LT. An expanded set of genome-wide association studies of brain imaging phenotypes in UK Biobank. Nat Neurosci 2021; 24:737-745. [PMID: 33875891 PMCID: PMC7610742 DOI: 10.1038/s41593-021-00826-4] [Citation(s) in RCA: 170] [Impact Index Per Article: 56.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 02/23/2021] [Indexed: 02/01/2023]
Abstract
UK Biobank is a major prospective epidemiological study, including multimodal brain imaging, genetics and ongoing health outcomes. Previously, we published genome-wide associations of 3,144 brain imaging-derived phenotypes, with a discovery sample of 8,428 individuals. Here we present a new open resource of genome-wide association study summary statistics, using the 2020 data release, almost tripling the discovery sample size. We now include the X chromosome and new classes of imaging-derived phenotypes (subcortical volumes and tissue contrast). Previously, we found 148 replicated clusters of associations between genetic variants and imaging phenotypes; in this study, we found 692, including 12 on the X chromosome. We describe some of the newly found associations, focusing on the X chromosome and autosomal associations involving the new classes of imaging-derived phenotypes. Our novel associations implicate, for example, pathways involved in the rare X-linked STAR (syndactyly, telecanthus and anogenital and renal malformations) syndrome, Alzheimer's disease and mitochondrial disorders.
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Affiliation(s)
- Stephen M Smith
- Wellcome Centre for Integrative Neuroimaging (WIN FMRIB), University of Oxford, Oxford, United Kingdom
| | - Gwenaëlle Douaud
- Wellcome Centre for Integrative Neuroimaging (WIN FMRIB), University of Oxford, Oxford, United Kingdom
| | - Winfield Chen
- Department of Statistics and Actuarial Science, Simon Fraser University, Burnaby BC, Canada
| | - Taylor Hanayik
- Wellcome Centre for Integrative Neuroimaging (WIN FMRIB), University of Oxford, Oxford, United Kingdom
| | - Fidel Alfaro-Almagro
- Wellcome Centre for Integrative Neuroimaging (WIN FMRIB), University of Oxford, Oxford, United Kingdom
| | | | - Lloyd T Elliott
- Department of Statistics and Actuarial Science, Simon Fraser University, Burnaby BC, Canada.
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17
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RAB39B-mediated trafficking of the GluA2-AMPAR subunit controls dendritic spine maturation and intellectual disability-related behaviour. Mol Psychiatry 2021; 26:6531-6549. [PMID: 34035473 PMCID: PMC8760075 DOI: 10.1038/s41380-021-01155-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 04/19/2021] [Accepted: 05/04/2021] [Indexed: 12/17/2022]
Abstract
Mutations in the RAB39B gene cause X-linked intellectual disability (XLID), comorbid with autism spectrum disorders or early Parkinson's disease. One of the functions of the neuronal small GTPase RAB39B is to drive GluA2/GluA3 α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) maturation and trafficking, determining AMPAR subunit composition at glutamatergic postsynaptic neuronal terminals. Taking advantage of the Rab39b knockout murine model, we show that a lack of RAB39B affects neuronal dendritic spine refinement, prompting a more Ca2+-permeable and excitable synaptic network, which correlates with an immature spine arrangement and behavioural and cognitive alterations in adult mice. The persistence of immature circuits is triggered by increased hypermobility of the spine, which is restored by the Ca2+-permeable AMPAR antagonist NASPM. Together, these data confirm that RAB39B controls AMPAR trafficking, which in turn plays a pivotal role in neuronal dendritic spine remodelling and that targeting Ca2+-permeable AMPARs may highlight future pharmaceutical interventions for RAB39B-associated disease conditions.
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18
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Stutterd CA, Brock S, Stouffs K, Fanjul-Fernandez M, Lockhart PJ, McGillivray G, Mandelstam S, Pope K, Delatycki MB, Jansen A, Leventer RJ. Genetic heterogeneity of polymicrogyria: study of 123 patients using deep sequencing. Brain Commun 2020; 3:fcaa221. [PMID: 33604570 PMCID: PMC7878248 DOI: 10.1093/braincomms/fcaa221] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 10/23/2020] [Accepted: 10/27/2020] [Indexed: 12/29/2022] Open
Abstract
Polymicrogyria is a malformation of cortical development characterized by overfolding and abnormal lamination of the cerebral cortex. Manifestations include epilepsy, speech disturbance and motor and cognitive disability. Causes include acquired prenatal insults and inherited and de novo genetic variants. The proportion of patients with polymicrogyria and a causative germline or mosaic variant is not known. The aim of this study was to identify the monogenic causes of polymicrogyria in a heterogeneous cohort of patients reflective of specialized referral services. Patients with polymicrogyria were recruited from two clinical centres in Australia and Belgium. Patients with evidence of congenital cytomegalovirus infection or causative chromosomal copy number variants were excluded. One hundred and twenty-three patients were tested using deep sequencing gene panels including known and candidate genes for malformations of cortical development. Causative and potentially causative variants were identified and correlated with phenotypic features. Pathogenic or likely pathogenic variants were identified in 25/123 (20.3%) patients. A candidate variant was identified for an additional patient but could not be confirmed as de novo, and therefore it was classified as being of uncertain significance with high clinical relevance. Of the 22 dominant variants identified, 5 were mosaic with allele fractions less than 0.33 and the lowest allele fraction 0.09. The most common causative genes were TUBA1A and PIK3R2. The other eleven causative genes were PIK3CA, NEDD4L, COL4A1, COL4A2, GPSM2, GRIN2B, WDR62, TUBB3, TUBB2B, ACTG1 and FH. A genetic cause was more likely to be identified in the presence of an abnormal head size or additional brain malformations suggestive of a tubulinopathy, such as dysmorphic basal ganglia. A gene panel test provides greater sequencing depth and sensitivity for mosaic variants than whole exome or genome sequencing but is limited to the genes included, potentially missing variants in newly discovered genes. The diagnostic yield of 20.3% indicates that polymicrogyria may be associated with genes not yet known to be associated with brain malformations, brain-specific somatic mutations or non-genetic causes.
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Affiliation(s)
- Chloe A Stutterd
- Murdoch Children's Research Institute, Melbourne, 3052, Australia.,University of Melbourne Department of Paediatrics, Melbourne, 3052, Australia.,Royal Children's Hospital, Melbourne, 3052, Australia.,Victorian Clinical Genetics Service, Melbourne, 3052, Australia
| | - Stefanie Brock
- Neurogenetics Research group, Vrije Universiteit Brussel, Belgium.,Department of Pathology, UZ Brussel, Belgium
| | - Katrien Stouffs
- Neurogenetics Research group, Vrije Universiteit Brussel, Belgium.,Centre for Medical Genetics, UZ Brussel, Belgium
| | | | - Paul J Lockhart
- Murdoch Children's Research Institute, Melbourne, 3052, Australia.,University of Melbourne Department of Paediatrics, Melbourne, 3052, Australia
| | | | - Simone Mandelstam
- Murdoch Children's Research Institute, Melbourne, 3052, Australia.,University of Melbourne Department of Paediatrics, Melbourne, 3052, Australia.,Royal Children's Hospital, Melbourne, 3052, Australia
| | - Kate Pope
- Murdoch Children's Research Institute, Melbourne, 3052, Australia
| | - Martin B Delatycki
- Murdoch Children's Research Institute, Melbourne, 3052, Australia.,University of Melbourne Department of Paediatrics, Melbourne, 3052, Australia.,Victorian Clinical Genetics Service, Melbourne, 3052, Australia
| | - Anna Jansen
- Neurogenetics Research group, Vrije Universiteit Brussel, Belgium.,Pediatric Neurology Unit, UZ Brussel, Belgium
| | - Richard J Leventer
- Murdoch Children's Research Institute, Melbourne, 3052, Australia.,University of Melbourne Department of Paediatrics, Melbourne, 3052, Australia.,Royal Children's Hospital, Melbourne, 3052, Australia
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19
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Santoro C, Giugliano T, Bernardo P, Palladino F, Torella A, Del Vecchio Blanco F, Onore ME, Carotenuto M, Nigro V, Piluso G. A novel RAB39B mutation and concurrent de novo NF1 mutation in a boy with neurofibromatosis type 1, intellectual disability, and autism: a case report. BMC Neurol 2020; 20:327. [PMID: 32873259 PMCID: PMC7460788 DOI: 10.1186/s12883-020-01911-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 08/26/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Mutations in RAB39B at Xq28 causes a rare form of X-linked intellectual disability (ID) and Parkinson's disease. Neurofibromatosis type 1 (NF1) is caused by heterozygous mutations in NF1 occurring de novo in about 50% of cases, usually due to paternal gonadal mutations. This case report describes clinical and genetic findings in a boy with the occurrence of two distinct causative mutations in NF1 and RAB39B explaining the observed phenotype. CASE PRESENTATION Here we report a 7-year-old boy with multiple café-au-lait macules (CALMs) and freckling, severe macrocephaly, peculiar facial gestalt, severe ID with absent speech, epilepsy, autistic traits, self-harming, and aggressiveness. Proband is an only child born to a father aged 47. Parents did not present signs of NF1, while a maternal uncle showed severe ID, epilepsy, and tremors.By RNA analysis of NF1, we identified a de novo splicing variant (NM_000267.3:c.6579+2T>C) in proband, which explained NF1 clinical features but not the severe ID, behavioral problems, and aggressiveness. Family history suggested an X-linked condition and massively parallel sequencing of X-exome identified a novel RAB39B mutation (NM_171998.2:c.436_447del) in proband, his mother, and affected maternal uncle, subsequently validated by Sanger sequencing in these and other family members. CONCLUSIONS The case presented here highlights how concurrent genetic defects should be considered in NF1 patients when NF1 mutations cannot reasonably explain all the observed clinical features.
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Affiliation(s)
- Claudia Santoro
- Department of Physical and Mental Health, and Preventive Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy.,Department of Women, Children, and General and Specialized Surgery, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Teresa Giugliano
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Via Luigi De Crecchio,7 -, 80138, Naples, Italy
| | - Pia Bernardo
- Department of Neurosciences, Pediatric Hospital Santobono-Pausilipon, Naples, Italy
| | - Federica Palladino
- Department of Women, Children, and General and Specialized Surgery, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Annalaura Torella
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Via Luigi De Crecchio,7 -, 80138, Naples, Italy
| | - Francesca Del Vecchio Blanco
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Via Luigi De Crecchio,7 -, 80138, Naples, Italy
| | - Maria Elena Onore
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Via Luigi De Crecchio,7 -, 80138, Naples, Italy
| | - Marco Carotenuto
- Department of Physical and Mental Health, and Preventive Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Vincenzo Nigro
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Via Luigi De Crecchio,7 -, 80138, Naples, Italy.,Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
| | - Giulio Piluso
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Via Luigi De Crecchio,7 -, 80138, Naples, Italy.
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20
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Tang BL. RAB39B's role in membrane traffic, autophagy, and associated neuropathology. J Cell Physiol 2020; 236:1579-1592. [PMID: 32761840 DOI: 10.1002/jcp.29962] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/19/2020] [Accepted: 07/13/2020] [Indexed: 12/14/2022]
Abstract
Neuropathological disorders are increasingly associated with dysfunctions in neuronal membrane traffic and autophagy, with defects among members of the Rab family of small GTPases implicated. Mutations in the human Xq28 localized gene RAB39B have been associated with X-linked neurodevelopmental defects including macrocephaly, intellectual disability, autism spectrum disorder (ASD), as well as rare cases of early-onset Parkinson's disease (PD). Despite the finding that RAB39B regulates GluA2 trafficking and could thus influence synaptic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor subunit composition, reasons for the wide-ranging neuropathological consequences associated with RAB39B defects have been unclear. Recent studies have now unraveled possible mechanisms underlying the neuropathological roles of this brain-enriched small GTPase. Studies in RAB39B knockout mice showed that RAB39B interacts with components of Class I phosphatidylinositol-3-kinase (PI3K) signaling. In its absence, the PI3K-AKT-mechanistic target of rapamycin signaling pathway in neural progenitor cells (NPCs) is hyperactivated, which promotes NPC proliferation, leading to macrocephaly and ASD. Pertaining to early-onset PD, a complex of C9orf72, Smith-Magenis syndrome chromosome region candidate 8 and WD repeat domain 41 that functions in autophagy has been identified as a guanine nucleotide exchange factor of RAB39B. Here, recent findings that have shed light on our mechanistic understanding of RAB39B's role in neurodevelopmental and neurodegenerative pathologies are reviewed. Caveats and unanswered questions are also discussed, and future perspectives outlined.
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Affiliation(s)
- Bor Luen Tang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,NUS Graduate School of Integrative Sciences and Engineering, National University of Singapore, Singapore
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21
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Gao Y, Wilson GR, Salce N, Romano A, Mellick GD, Stephenson SEM, Lockhart PJ. Genetic Analysis of RAB39B in an Early-Onset Parkinson's Disease Cohort. Front Neurol 2020; 11:523. [PMID: 32670181 PMCID: PMC7332711 DOI: 10.3389/fneur.2020.00523] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 05/12/2020] [Indexed: 12/12/2022] Open
Abstract
Pathogenic variants in the gene encoding RAB39B, resulting in the loss of protein function, lead to the development of X-linked early-onset parkinsonism. The gene is located within a chromosomal region that is susceptible to genomic rearrangement, and while an increased dosage of RAB39B was previously associated with cognitive impairment, the potential role of dosage alterations in Parkinson's disease (PD) remains to be determined. This study aimed to investigate the contribution of the genetic variation in RAB39B to the development of early-onset PD. We performed gene dosage studies and sequence analysis in a cohort of 176 individuals with early-onset PD (age of onset ≤ 50 years) of unknown genetic etiology. An assessment of the copy number variation over both coding exons and the 3' untranslated region (UTR) of RAB39B did not identify any alterations in gene dosage. An analysis of the UTRs identified two male individuals carrying single, likely benign, nucleotide variants in the 3'UTR (chrX:154489749-A-G and chrX:154489197-T-G). Furthermore, one novel variant of uncertain significance was identified in the 5'UTR, 229 bp upstream of the start codon (chrX:154493802-C-T). In silico analyses predicted that this variant disrupts a highly conserved transcription factor binding site and could impact RAB39B expression. The results of this study do not support a significant role for genetic variation in RAB39B as contributing to early-onset PD but do highlight that additional molecular studies are required to determine the mechanisms regulating RAB39B expression and their association with the disease. Genetic investigations in larger parkinsonism/PD cohorts and longitudinal studies of individuals with cognitive impairment due to an altered dosage of RAB39B will be required to fully delineate the contribution of RAB39B to parkinsonism.
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Affiliation(s)
- Yujing Gao
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | - Gabrielle R Wilson
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | - Nicholas Salce
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne, VIC, Australia
| | - Alexandra Romano
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia
| | - George D Mellick
- Griffith Institute for Drug Discovery (GRIDD), Griffith University, Nathan, QLD, Australia
| | - Sarah E M Stephenson
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | - Paul J Lockhart
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
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22
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Amano G, Matsuzaki S, Mori Y, Miyoshi K, Han S, Shikada S, Takamura H, Yoshimura T, Katayama T. SCYL1 arginine methylation by PRMT1 is essential for neurite outgrowth via Golgi morphogenesis. Mol Biol Cell 2020; 31:1963-1973. [PMID: 32583741 PMCID: PMC7543066 DOI: 10.1091/mbc.e20-02-0100] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Arginine methylation is a common posttranslational modification that modulates protein function. SCY1-like pseudokinase 1 (SCYL1) is crucial for neuronal functions and interacts with γ2-COP to form coat protein complex I (COPI) vesicles that regulate Golgi morphology. However, the molecular mechanism by which SCYL1 is regulated remains unclear. Here, we report that the γ2-COP-binding site of SCYL1 is arginine-methylated by protein arginine methyltransferase 1 (PRMT1) and that SCYL1 arginine methylation is important for the interaction of SCYL1 with γ2-COP. PRMT1 was colocalized with SCYL1 in the Golgi fraction. Inhibition of PRMT1 suppressed axon outgrowth and dendrite complexity via abnormal Golgi morphology. Knockdown of SCYL1 by small interfering RNA (siRNA) inhibited axon outgrowth, and the inhibitory effect was rescued by siRNA-resistant SCYL1, but not SCYL1 mutant, in which the arginine methylation site was replaced. Thus, PRMT1 regulates Golgi morphogenesis via SCYL1 arginine methylation. We propose that SCYL1 arginine methylation by PRMT1 contributes to axon and dendrite morphogenesis in neurons.
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Affiliation(s)
- Genki Amano
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Shinsuke Matsuzaki
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.,Department of Pharmacology, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-0012, Japan
| | - Yasutake Mori
- Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.,Department of Anatomy, International University of Health and Welfare, 4-3 Kozunomori, Narita, Chiba, 286-8686, Japan
| | - Ko Miyoshi
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Sarina Han
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Sho Shikada
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Hironori Takamura
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Takeshi Yoshimura
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Taiichi Katayama
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
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23
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Gao Y, Wilson GR, Stephenson SEM, Oulad-Abdelghani M, Charlet-Berguerand N, Bozaoglu K, McLean CA, Thomas PQ, Finkelstein DI, Lockhart PJ. Distribution of Parkinson's disease associated RAB39B in mouse brain tissue. Mol Brain 2020; 13:52. [PMID: 32228644 PMCID: PMC7106796 DOI: 10.1186/s13041-020-00584-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 03/10/2020] [Indexed: 12/22/2022] Open
Abstract
Pathogenic variants in the gene encoding the small GTPase Ras analogue in Brain 39b (RAB39B) are associated with early-onset parkinsonism. In this study we investigated the expression and localization of RAB39B (RNA and protein) in mouse brain tissue to gain a better understanding of its normal physiological function(s) and role in disease. We developed novel resources, including monoclonal antibodies directed against RAB39B and mice with Rab39b knockout, and performed real-time PCR and western blot analysis on whole brain lysates. To determine the spatial localization of Rab39b RNA and protein, we performed in-situ hybridization and immunohistochemistry on fresh frozen and fixed brain tissue. Our results show that RAB39B is localized throughout the cortex, hippocampus and substantia nigra of mice throughout postnatal life. We found high levels of RAB39B within MAP2 positive cortical and hippocampal neurons, and TH positive dopaminergic neurons in the substantia nigra pars compacta. Our studies support and extend current knowledge of the localization of RAB39B. We validate RAB39B as a neuron-enriched protein and demonstrate that it is present throughout the mouse cortex and hippocampus. Further, we observe high levels in the substantia nigra pars compacta, the brain region most affected in Parkinson’s disease pathology. The distribution of Rab39b is consistent with human disease associations with parkinsonism and cognitive impairment. We also describe and validate novel resources, including monoclonal antibodies directed against RAB39B and mice with Rab39b knockout, both of which are valuable tools for future studies of the molecular function of RAB39B.
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Affiliation(s)
- Yujing Gao
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, 50 Flemington Road, Parkville, Victoria, 3052, Australia.,Department of Paediatrics, The University of Melbourne, 30 Royal Parade, Parkville, Victoria, 3052, Australia
| | - Gabrielle R Wilson
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, 50 Flemington Road, Parkville, Victoria, 3052, Australia.,Department of Paediatrics, The University of Melbourne, 30 Royal Parade, Parkville, Victoria, 3052, Australia
| | - Sarah E M Stephenson
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, 50 Flemington Road, Parkville, Victoria, 3052, Australia.,Department of Paediatrics, The University of Melbourne, 30 Royal Parade, Parkville, Victoria, 3052, Australia
| | - Mustapha Oulad-Abdelghani
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, Strasbourg University, 67400, Illkirch, France
| | - Nicolas Charlet-Berguerand
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, Strasbourg University, 67400, Illkirch, France
| | - Kiymet Bozaoglu
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, 50 Flemington Road, Parkville, Victoria, 3052, Australia.,Department of Paediatrics, The University of Melbourne, 30 Royal Parade, Parkville, Victoria, 3052, Australia
| | - Catriona A McLean
- Anatomical Pathology, Alfred Hospital, Melbourne, Victoria, 3004, Australia
| | - Paul Q Thomas
- Robinson Research Institute and School of Medicine, University of Adelaide, Adelaide, SA, 5005, Australia
| | - David I Finkelstein
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, Victoria, 3052, Australia
| | - Paul J Lockhart
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, 50 Flemington Road, Parkville, Victoria, 3052, Australia. .,Department of Paediatrics, The University of Melbourne, 30 Royal Parade, Parkville, Victoria, 3052, Australia.
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24
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Ballout RA, Dickerson C, Wick MJ, Al-Sweel N, Openshaw AS, Srivastava S, Swanson LC, Bramswig NC, Kuechler A, Hong B, Fleming LR, Curry K, Robertson SP, Andersen EF, El-Hattab AW. Int22h1/Int22h2-mediated Xq28 duplication syndrome: de novo duplications, prenatal diagnoses, and additional phenotypic features. Hum Mutat 2020; 41:1238-1249. [PMID: 32112660 DOI: 10.1002/humu.24009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 02/25/2020] [Accepted: 02/27/2020] [Indexed: 12/11/2022]
Abstract
Int22h1/Int22h2-mediated Xq28 duplication syndrome is a relatively new X-linked intellectual disability syndrome, arising from duplications of the subregion flanked by intron 22 homologous regions 1 and 2 on the q arm of chromosome X. Its primary manifestations include variable cognitive deficits, distinct facial dysmorphia, and neurobehavioral abnormalities that mainly include hyperactivity, irritability, and autistic behavior. Affected males are hemizygous for the duplication, which explains their often more severe manifestations compared with heterozygous females. In this report, we describe the cases of nine individuals recently identified having the syndrome, highlighting unique and previously unreported findings of this syndrome. Specifically, we report for the first time in this syndrome, two cases with de novo duplications, three receiving prenatal diagnosis with the syndrome, and three others having atypical versions of the duplication. Among the latter, one proband has a shortened version spanning only the centromeric half of the typical duplication, while the other two cases have a nearly identical length duplication as the classical duplication, with the exception that their duplication's breakpoints are telomerically shifted by about 0.2 Mb. Finally, we shed light on two new manifestations in this syndrome, vertebral anomalies and multiple malignancies, which possibly expand the phenotypic spectrum of the syndrome.
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Affiliation(s)
- Rami A Ballout
- Lipoprotein Metabolism Section, Translational Vascular Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland.,Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Cheryl Dickerson
- WakeMed Physician Practices, Maternal-Fetal Medicine, Raleigh, North Carolina
| | - Myra J Wick
- Departments of Obstetrics and Gynecology and Clinical Genomics, Mayo Clinic, Rochester, Minnesota
| | - Najla Al-Sweel
- Department of Pathology, University of Utah, Salt Lake City, Utah.,ARUP Laboratories, Cytogenetics and Genomic Microarray, Salt Lake City, Utah
| | - Amanda S Openshaw
- ARUP Laboratories, Cytogenetics and Genomic Microarray, Salt Lake City, Utah
| | | | - Lindsay C Swanson
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts
| | - Nuria C Bramswig
- Institut für Humangenetik, Universitätsklinikum Essen, Universität Duisburg-Essen, Essen, Germany
| | - Alma Kuechler
- Institut für Humangenetik, Universitätsklinikum Essen, Universität Duisburg-Essen, Essen, Germany
| | - Bo Hong
- Department of Pathology, University of Utah, Salt Lake City, Utah.,ARUP Laboratories, Cytogenetics and Genomic Microarray, Salt Lake City, Utah
| | - Leah R Fleming
- St. Luke's Children's Genetics and Metabolic Clinic, Boise, Idaho
| | - Kathryn Curry
- St. Luke's Children's Genetics and Metabolic Clinic, Boise, Idaho
| | - Stephen P Robertson
- Department of Women's and Children's Health, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Erica F Andersen
- Department of Pathology, University of Utah, Salt Lake City, Utah.,ARUP Laboratories, Cytogenetics and Genomic Microarray, Salt Lake City, Utah
| | - Ayman W El-Hattab
- Department of Clinical Sciences, College of Medicine, University of Sharjah, Sharjah, UAE
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25
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Gao Y, Martínez-Cerdeño V, Hogan KJ, McLean CA, Lockhart PJ. Clinical and Neuropathological Features Associated With Loss of RAB39B. Mov Disord 2020; 35:687-693. [PMID: 31951675 DOI: 10.1002/mds.27951] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 11/10/2019] [Accepted: 11/25/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Pathogenic variants in the small GTPase Ras Analogue in Brain 39b (RAB39B) have been linked to the development of early-onset parkinsonism. The study was aimed at delineating the clinical and neuropathological features associated with a previously reported pathogenic variant in RAB39B (c.503C>A p.T168K) and testing for dysregulation of RAB39B in idiopathic PD. METHODS Clinical details of a male individual hemizygous for the T168K variant were collected by systematic review of medical records. Neuropathological studies of fixed brain tissue were performed and steady-state RAB39B levels were determined by western blot analysis. RESULTS Neuropathological examination showed extensive dopaminergic neuron loss, widespread Lewy pathology, and iron accumulation in the substantia nigra. Additional pathology was observed in the hippocampus and thalamus. Western blot analysis demonstrated that the T168K variant results in loss of RAB39B. In individuals with idiopathic PD (n = 10, 6 male/4 female), steady-state RAB39B was significantly reduced in the prefrontal cortex and substantia nigra. CONCLUSIONS T168K RAB39B is unstable in vivo and associated with dopaminergic neuron loss and Lewy pathology. Dysregulation of RAB39B in the prefrontal cortex and substantia nigra of individuals with idiopathic PD potentially implicates the protein more broadly in the pathological mechanisms underlying PD and related Lewy body disorders. © 2020 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Yujing Gao
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia
- Department of Pediatrics, The University of Melbourne, Melbourne, Victoria, Australia
| | - Verónica Martínez-Cerdeño
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine; Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children of Northern California, Davis, California, USA
- MIND Institute, UC Davis Medical Center, Davis, California, USA
| | - Kirk J Hogan
- Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
- Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Catriona A McLean
- Anatomical Pathology, Alfred Hospital, Melbourne, Victoria, Australia
| | - Paul J Lockhart
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia
- Department of Pediatrics, The University of Melbourne, Melbourne, Victoria, Australia
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26
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Rab39a and Rab39b Display Different Intracellular Distribution and Function in Sphingolipids and Phospholipids Transport. Int J Mol Sci 2019; 20:ijms20071688. [PMID: 30987349 PMCID: PMC6480249 DOI: 10.3390/ijms20071688] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/14/2019] [Accepted: 03/27/2019] [Indexed: 12/23/2022] Open
Abstract
Rab GTPases define the identity and destiny of vesicles. Some of these small GTPases present isoforms that are expressed differentially along developmental stages or in a tissue-specific manner, hence comparative analysis is difficult to achieve. Here, we describe the intracellular distribution and function in lipid transport of the poorly characterized Rab39 isoforms using typical cell biology experimental tools and new ones developed in our laboratory. We show that, despite their amino acid sequence similarity, Rab39a and Rab39b display non-overlapping intracellular distribution. Rab39a localizes in the late endocytic pathway, mainly at multivesicular bodies. In contrast, Rab39b distributes in the secretory network, at the endoplasmic reticulum/cis-Golgi interface. Therefore, Rab39a controls trafficking of lipids (sphingomyelin and phospholipids) segregated at multivesicular bodies, whereas Rab39b transports sphingolipids biosynthesized at the endoplasmic reticulum-Golgi factory. Interestingly, lyso bis-phosphatidic acid is exclusively transported by Rab39a, indicating that both isoforms do not exert identical functions in lipid transport. Conveniently, the requirement of eukaryotic lipids by the intracellular pathogen Chlamydia trachomatis rendered useful for dissecting and distinguishing Rab39a- and Rab39b-controlled trafficking pathways. Our findings provide comparative insights about the different subcellular distribution and function in lipid transport of the two Rab39 isoforms.
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27
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Peters SU, Fu C, Suter B, Marsh E, Benke TA, Skinner SA, Lieberman DN, Standridge S, Jones M, Beisang A, Feyma T, Heydeman P, Ryther R, Kaufmann WE, Glaze DG, Neul JL, Percy AK. Characterizing the phenotypic effect of Xq28 duplication size in MECP2 duplication syndrome. Clin Genet 2019; 95:575-581. [PMID: 30788845 DOI: 10.1111/cge.13521] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 02/01/2019] [Accepted: 02/05/2019] [Indexed: 12/11/2022]
Abstract
Individuals with methyl CpG binding protein 2 (MECP2) duplication syndrome (MDS) have varying degrees of severity in their mobility, hand use, developmental skills, and susceptibility to infections. In the present study, we examine the relationship between duplication size, gene content, and overall phenotype in MDS using a clinical severity scale. Other genes typically duplicated within Xq28 (eg, GDI1, RAB39B, FLNA) are associated with distinct clinical features independent of MECP2. We additionally compare the phenotype of this cohort (n = 48) to other reported cohorts with MDS. Utilizing existing indices of clinical severity in Rett syndrome, we found that larger duplication size correlates with higher severity in total clinical severity scores (r = 0.36; P = 0.02), and in total motor behavioral assessment inventory scores (r = 0.31; P = 0.05). Greater severity was associated with having the RAB39B gene duplicated, although most of these participants also had large duplications. Results suggest that developmental delays in the first 6 months of life, hypotonia, vasomotor disturbances, constipation, drooling, and bruxism are common in MDS. This is the first study to show that duplication size is related to clinical severity. Future studies should examine whether large duplications which do not encompass RAB39B also contribute to clinical severity. Results also suggest the need for creating an MDS specific severity scale.
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Affiliation(s)
- Sarika U Peters
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Cary Fu
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Bernhard Suter
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas
| | - Eric Marsh
- Division of Neurology and Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Timothy A Benke
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | | | - David N Lieberman
- Department of Pediatrics, Boston Children's Hospital, Boston, Massachusetts
| | - Shannon Standridge
- Department of Pediatrics, Cincinnati Children's Hospital, Cincinnati, Ohio
| | - Mary Jones
- Department of Pediatrics, UCSF Benioff Children's Hospital, Oakland, California
| | - Arthur Beisang
- Department of Pediatrics, Gilette Children's Specialty Healthcare, Saint Paul, Minnesota
| | - Timothy Feyma
- Department of Pediatrics, Gilette Children's Specialty Healthcare, Saint Paul, Minnesota
| | - Peter Heydeman
- Department of Pediatrics, Rush University Medical Center, Chicago, Illinois
| | - Robin Ryther
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri
| | | | - Daniel G Glaze
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas
| | - Jeffrey L Neul
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Alan K Percy
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama
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28
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Lannoy N, Hermans C. Review of molecular mechanisms at distal Xq28 leading to balanced or unbalanced genomic rearrangements and their phenotypic impacts on hemophilia. Haemophilia 2018; 24:711-719. [DOI: 10.1111/hae.13569] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/09/2018] [Indexed: 01/18/2023]
Affiliation(s)
- N. Lannoy
- Hemostasis and Thrombosis Unit; Hemophilia Clinic; Division of Hematology; Cliniques Universitaires Saint-Luc; Brussels Belgium
| | - C. Hermans
- Hemostasis and Thrombosis Unit; Hemophilia Clinic; Division of Hematology; Cliniques Universitaires Saint-Luc; Brussels Belgium
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29
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Jorge P, Garcia E, Gonçalves A, Marques I, Maia N, Rodrigues B, Santos H, Fonseca J, Soares G, Correia C, Reis-Lima M, Cirigliano V, Santos R. Classical fragile-X phenotype in a female infant disclosed by comprehensive genomic studies. BMC MEDICAL GENETICS 2018; 19:74. [PMID: 29747568 PMCID: PMC5946481 DOI: 10.1186/s12881-018-0589-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 04/19/2018] [Indexed: 11/23/2022]
Abstract
Background We describe a female infant with Fragile-X syndrome, with a fully expanded FMR1 allele and preferential inactivation of the homologous X-chromosome carrying a de novo deletion. This unusual and rare case demonstrates the importance of a detailed genomic approach, the absence of which could be misguiding, and calls for reflection on the current clinical and diagnostic workup for developmental disabilities. Case presentation We present a female infant, referred for genetic testing due to psychomotor developmental delay without specific dysmorphic features or relevant family history. FMR1 mutation screening revealed a methylated full mutation and a normal but inactive FMR1 allele, which led to further investigation. Complete skewing of X-chromosome inactivation towards the paternally-inherited normal-sized FMR1 allele was found. No pathogenic variants were identified in the XIST promoter. Microarray analysis revealed a 439 kb deletion at Xq28, in a region known to be associated with extreme skewing of X-chromosome inactivation. Conclusions Overall results enable us to conclude that the developmental delay is the cumulative result of a methylated FMR1 full mutation on the active X-chromosome and the inactivation of the other homologue carrying the de novo 439 kb deletion. Our findings should be taken into consideration in future guidelines for the diagnostic workup on the diagnosis of intellectual disabilities, particularly in female infant cases.
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Affiliation(s)
- Paula Jorge
- Centro de Genética Médica Jacinto de Magalhães (CGMJM), Centro Hospitalar do Porto, CHP, E.P.E., Praça Pedro Nunes, 88 4099-028, Porto, Portugal. .,Unit for Multidisciplinary Research in Biomedicine, Abel Salazar Institute of Biomedical Sciences, University of Porto - UMIB-ICBAS-UP, Porto, Portugal.
| | - Elsa Garcia
- GDPN - Labco diagnostics, Synlab Group, Genética e Diagnóstico Pré-natal, Porto, Portugal
| | - Ana Gonçalves
- Unit for Multidisciplinary Research in Biomedicine, Abel Salazar Institute of Biomedical Sciences, University of Porto - UMIB-ICBAS-UP, Porto, Portugal.,Unidade de genética molecular, Centro de Genética Médica Jacinto de Magalhães, Centro Hospitalar do Porto, CHP, E.P.E, Porto, Portugal
| | - Isabel Marques
- Unit for Multidisciplinary Research in Biomedicine, Abel Salazar Institute of Biomedical Sciences, University of Porto - UMIB-ICBAS-UP, Porto, Portugal.,Unidade de genética molecular, Centro de Genética Médica Jacinto de Magalhães, Centro Hospitalar do Porto, CHP, E.P.E, Porto, Portugal
| | - Nuno Maia
- Unit for Multidisciplinary Research in Biomedicine, Abel Salazar Institute of Biomedical Sciences, University of Porto - UMIB-ICBAS-UP, Porto, Portugal.,Unidade de genética molecular, Centro de Genética Médica Jacinto de Magalhães, Centro Hospitalar do Porto, CHP, E.P.E, Porto, Portugal
| | - Bárbara Rodrigues
- Mestranda Biologia Molecular e Celular Universidade de Aveiro, Unidade de Genética Molecular, Centro de Genética Médica Jacinto de Magalhães, Centro Hospitalar do Porto, CHP, E.P.E, Porto, Portugal
| | - Helena Santos
- Unidade de Neurociências da criança e adolescente, Serviço de Pediatria, Centro Hospitalar de Vila Nova de Gaia/Espinho (C.H.V.N.Gaia/Espinho), E.P.E, Vila Nova de Gaia, Portugal
| | - Jacinta Fonseca
- Unidade de Neurociências da criança e adolescente, Serviço de Pediatria, Centro Hospitalar de Vila Nova de Gaia/Espinho (C.H.V.N.Gaia/Espinho), E.P.E, Vila Nova de Gaia, Portugal
| | - Gabriela Soares
- Unidade de genética médica, Centro de Genética Médica Jacinto de Magalhães, Centro Hospitalar do Porto, CHP, E.P.E, Porto, Portugal
| | - Cecília Correia
- GDPN- Labco diagnostics, Synlab Group, Genética e Diagnóstico Pré-natal, Porto, Portugal
| | - Margarida Reis-Lima
- GDPN- Labco diagnostics, Synlab Group, Genética e Diagnóstico Pré-natal, Porto, Portugal
| | - Vincenzo Cirigliano
- Department of Molecular Genetics, Labco diagnostics, Synlab Group, Esplugues de Llobregat, Barcelona, Spain
| | - Rosário Santos
- Unit for Multidisciplinary Research in Biomedicine, Abel Salazar Institute of Biomedical Sciences, University of Porto - UMIB-ICBAS-UP, Porto, Portugal.,Unidade de genética molecular, Centro de Genética Médica Jacinto de Magalhães, Centro Hospitalar do Porto, CHP, E.P.E, Porto, Portugal.,UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
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30
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Ward DI, Buckley BA, Leon E, Diaz J, Galegos MF, Hofherr S, Lewanda AF. Intellectual disability and epilepsy due to the K/L-mediated Xq28 duplication: Further evidence of a distinct, dosage-dependent phenotype. Am J Med Genet A 2018; 176:551-559. [PMID: 29341460 DOI: 10.1002/ajmg.a.38524] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 09/27/2017] [Accepted: 10/08/2017] [Indexed: 12/30/2022]
Abstract
Copy number variants of the X-chromosome are a common cause of X-linked intellectual disability in males. Duplication of the Xq28 band has been known for over a decade to be the cause of the Lubs X-linked Mental Retardation Syndrome (OMIM 300620) in males and this duplication has been narrowed to a critical region containing only the genes MECP2 and IRAK1. In 2009, four families with a distal duplication of Xq28 not including MECP2 and mediated by low-copy repeats (LCRs) designated "K" and "L" were reported with intellectual disability and epilepsy. Duplication of a second more distal region has been described as the cause of the Int22h-1/Int22h-2 Mediated Xq28 Duplication Syndrome, characterized by intellectual disability, psychiatric problems, and recurrent infections. We report two additional families possessing the K/L-mediated Xq28 duplication with affected males having intellectual disability and epilepsy similar to the previously reported phenotype. To our knowledge, this is the second cohort of individuals to be reported with this duplication and therefore supports K/L-mediated Xq28 duplications as a distinct syndrome.
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Affiliation(s)
- David Isum Ward
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Bethany A Buckley
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Eyby Leon
- Rare Disease Institute Genetics and Metabolism, Children's National Health System, Washington, District of Columbia
| | - Jullianne Diaz
- Rare Disease Institute Genetics and Metabolism, Children's National Health System, Washington, District of Columbia
| | - Margaret Faust Galegos
- Rare Disease Institute Genetics and Metabolism, Children's National Health System, Washington, District of Columbia
| | - Sean Hofherr
- Rare Disease Institute Genetics and Metabolism, Children's National Health System, Washington, District of Columbia
| | - Amy Feldman Lewanda
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, Maryland.,Rare Disease Institute Genetics and Metabolism, Children's National Health System, Washington, District of Columbia
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31
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Gao Y, Wilson GR, Stephenson SEM, Bozaoglu K, Farrer MJ, Lockhart PJ. The emerging role of Rab GTPases in the pathogenesis of Parkinson's disease. Mov Disord 2018; 33:196-207. [DOI: 10.1002/mds.27270] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Revised: 11/16/2017] [Accepted: 11/19/2017] [Indexed: 12/30/2022] Open
Affiliation(s)
- Yujing Gao
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute; Melbourne Victoria Australia
- Department of Paediatrics; The University of Melbourne; Melbourne Victoria Australia
| | - Gabrielle R. Wilson
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute; Melbourne Victoria Australia
- Department of Paediatrics; The University of Melbourne; Melbourne Victoria Australia
| | - Sarah E. M. Stephenson
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute; Melbourne Victoria Australia
- Department of Paediatrics; The University of Melbourne; Melbourne Victoria Australia
| | - Kiymet Bozaoglu
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute; Melbourne Victoria Australia
- Department of Paediatrics; The University of Melbourne; Melbourne Victoria Australia
| | - Matthew J. Farrer
- Djavad Mowafaghian Centre for Brain Health, Centre of Applied Neurogenetics, Department of Medical Genetics; University of British Columbia; Vancouver British Columbia Canada
| | - Paul J. Lockhart
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Children's Research Institute; Melbourne Victoria Australia
- Department of Paediatrics; The University of Melbourne; Melbourne Victoria Australia
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32
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Shi CH, Zhang SY, Yang ZH, Yang J, Shang DD, Mao CY, Liu H, Hou HM, Shi MM, Wu J, Xu YM. A novel RAB39B gene mutation in X-linked juvenile parkinsonism with basal ganglia calcification. Mov Disord 2017; 31:1905-1909. [PMID: 27943471 DOI: 10.1002/mds.26828] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 08/29/2016] [Accepted: 09/12/2016] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVES Mutations in RAB39B have been reported as a potential cause of X-linked Parkinson's disease (PD), a rare form of familial PD. We conducted a genetic analysis on RAB39B to evaluate whether RAB39B mutations are related to PD in the Chinese population. METHODS In this study, 2 patients from an X-linked juvenile parkinsonism pedigree were clinically characterized and underwent whole-exome sequencing. A comprehensive screening for RAB39B mutations in 505 sporadic patients with PD and 510 healthy controls in a Chinese population was also performed. RESULTS A novel mutation, c. 536dupA (p.E179fsX48), in RAB39B was identified in the juvenile parkinsonism pedigree. Brain MRI and CT scans in the 2 patients revealed calcification within the bilateral globus pallidus. No other potentially disease-causing RAB39B mutations were found in sporadic PD patients and controls. CONCLUSIONS X-linked juvenile parkinsonism could be caused by a RAB39B mutation, and basal ganglia calcification may be a novel clinical feature of RAB39B-related parkinsonism. © 2016 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Chang-He Shi
- Department of Neurology, The First affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
| | - Shu-Yu Zhang
- Department of Neurology, The First affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
| | - Zhi-Hua Yang
- Department of Neurology, The First affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China.,Institute of Clinical Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
| | - Jing Yang
- Department of Neurology, The First affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
| | - Dan-Dan Shang
- Department of Neurology, Luoyang Central Hospital Affiliated to Zhengzhou University, Luoyang, Henan, China
| | - Cheng-Yuan Mao
- Department of Neurology, The First affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
| | - Hao Liu
- Department of MRI, The First Affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
| | - Hai-Man Hou
- Department of Neurology, The First affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
| | - Meng-Meng Shi
- Department of Neurology, The First affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
| | - Jun Wu
- Department of Neurology, The First affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
| | - Yu-Ming Xu
- Department of Neurology, The First affiliated Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan, China
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Abstract
PURPOSE OF REVIEW This article reviews was to review genes where putative or confirmed pathogenic mutations causing Parkinson's disease or Parkinsonism have been identified since 2012, and summarizes the clinical and pathological picture of the associated disease subtypes. RECENT FINDINGS Newly reported genes for dominant Parkinson's disease are DNAJC13, CHCHD2, and TMEM230. However, the evidence for a disease-causing role is not conclusive, and further genetic and functional studies are warranted. RIC3 mutations have been reported from one family but not yet encountered in other patients. New genes for autosomal recessive disease include SYNJ1, DNAJC6, VPS13C, and PTRHD1. Deletions of a region on chromosome 22 (22q11.2del) are also associated with early-onset PD, but the mode of inheritance and the underlying causative gene remain unclear. PODXL mutations were reported in autosomal recessive PD, but their roles remain to be confirmed. Mutations in RAB39B cause an X-linked Parkinsonian disorder. Mutations in the new dominant PD genes have generally been found in medium- to late-onset Parkinson's disease. Many mutations in the new recessive and X-chromosomal genes cause severe atypical juvenile Parkinsonism, but less devastating mutations in these genes may cause PD.
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Affiliation(s)
- Andreas Puschmann
- Lund University, Skåne University Hospital, Department of Clinical Sciences Lund, Neurology, Lund, Sweden.
- Department for Neurology, Skåne University Hospital, Getingevägen 4, 224 67, Lund, Sweden.
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34
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Ciammola A, Carrera P, Di Fonzo A, Sassone J, Villa R, Poletti B, Ferrari M, Girotti F, Monfrini E, Buongarzone G, Silani V, Cinnante CM, Mignogna ML, D'Adamo P, Bonati MT. X-linked Parkinsonism with Intellectual Disability caused by novel mutations and somatic mosaicism in RAB39B gene. Parkinsonism Relat Disord 2017; 44:142-146. [PMID: 28851564 DOI: 10.1016/j.parkreldis.2017.08.021] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 08/10/2017] [Accepted: 08/20/2017] [Indexed: 12/15/2022]
Abstract
BACKGROUND RAB39B pathogenic variants cause X-linked Parkinsonism associated with Intellectual Disability, known as Waisman syndrome, a very rare disorder that has been mainly identified through exome sequencing in large Parkinson's disease cohorts. In this study we searched for pathogenic variants in RAB39B in two Italian families affected by X-linked early-onset Parkinsonism and Intellectual Disability. METHODS Three patients received neurological evaluation and underwent RAB39B sequencing. RESULTS Two novel RAB39B frameshift variants were found to result in the absence of RAB39B protein (family 1: c.137dupT; family 2: c.371delA). Patients showed unilateral rest tremor and bradykinesia; one of them also displayed an early-onset postural tremor. Paramagnetic substance deposition in the substantia nigra, globus pallidi, red nucleus, putamen and pulvinar was assessed by brain imaging. Two patients also showed moderate calcification of globus pallidi. CONCLUSION In this study we highlight the evidence that X-linked early-onset Parkinsonism associated with Intellectual Disability occurs as a pattern of clinical and neuroimaging features attributable to RAB39B pathogenic variants.
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Affiliation(s)
- Andrea Ciammola
- IRCCS Istituto Auxologico Italiano, Department of Neurology and Laboratory of Neuroscience, Milan, Italy
| | - Paola Carrera
- IRCCS San Raffaele Scientific Institute, Division of Genetics and Cell Biology, Unit of Genomics for Human Disease Diagnosis, Milan, Italy; IRCCS San Raffaele Scientific Institute Laboratory of Clinical Molecular Biology, Milan, Italy
| | - Alessio Di Fonzo
- IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy; Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Jenny Sassone
- San Raffaele Scientific Institute and Vita-Salute University, Milan, Italy
| | - Roberta Villa
- Clinic of Medical Genetics, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Barbara Poletti
- IRCCS Istituto Auxologico Italiano, Department of Neurology and Laboratory of Neuroscience, Milan, Italy
| | - Maurizio Ferrari
- IRCCS San Raffaele Scientific Institute Laboratory of Clinical Molecular Biology, Milan, Italy; Vita-Salute San Raffaele University, Chair of Clinical Pathology, Milan, Italy
| | - Floriano Girotti
- IRCCS Istituto Auxologico Italiano, Department of Neurology and Laboratory of Neuroscience, Milan, Italy
| | - Edoardo Monfrini
- IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy; Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Gabriele Buongarzone
- IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy; Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Vincenzo Silani
- IRCCS Istituto Auxologico Italiano, Department of Neurology and Laboratory of Neuroscience, Milan, Italy; Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Claudia Maria Cinnante
- Neuroradiology Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Maria Lidia Mignogna
- Molecular Genetics of Intellectual Disabilities Unit, Division of Neuroscience at IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Patrizia D'Adamo
- Molecular Genetics of Intellectual Disabilities Unit, Division of Neuroscience at IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Maria Teresa Bonati
- Clinic of Medical Genetics, IRCCS Istituto Auxologico Italiano, Milan, Italy.
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35
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Golgi trafficking defects in postnatal microcephaly: The evidence for “Golgipathies”. Prog Neurobiol 2017; 153:46-63. [DOI: 10.1016/j.pneurobio.2017.03.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 02/22/2017] [Accepted: 03/29/2017] [Indexed: 12/17/2022]
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36
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Jourdy Y, Chatron N, Fretigny M, Carage ML, Chambost H, Claeyssens-Donadel S, Roussel-Robert V, Negrier C, Sanlaville D, Vinciguerra C. Molecular cytogenetic characterization of five F8 complex rearrangements: utility for haemophilia A genetic counselling. Haemophilia 2017; 23:e316-e323. [PMID: 28475226 DOI: 10.1111/hae.13218] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/21/2017] [Indexed: 12/18/2022]
Abstract
BACKGROUND Genomic inversions are usually balanced, but unusual patterns have been described in haemophilia A (HA) patients for intron 22 (Inv22) and intron 1 (Inv1) inversions leading to the hypothesis of more complex rearrangements involving deletions or duplications. AIM To characterize five abnormal patterns either in Southern blot and long-range PCR for Inv22 or in PCR for Inv1. MATERIALS AND METHODS All patients were studied using cytogenetic microarray analysis (CMA). RESULTS In all cases, CMA analysis found that each inversion was associated with complex Xq28 rearrangement. In three patients, CMA analysis showed large duplication ranging from 230 to 1302 kb and encompassing a various number of contiguous genes among which RAB39B. RAB39B duplication is a strong candidate gene for X-linked intellectual disability (XLID). Surprisingly, none of the severe HA patients with RAB39B duplication reported in this study or in the literature exhibited XLID. We hypothesise that F8 complex rearrangement down regulated RAB39B expression. In the two remaining patients, CMA analysis found Xq28 large deletion (from 285 to 522 kb). Moyamoya syndrome was strongly suspected in one of them who carried BRCC3 deletion. CONCLUSION Because several F8 neighbouring genes are associated with other pathologies such as XLID and cardiovascular disease, all HA patients where complex Xq28 rearrangement was suspected should be referred to a geneticist for possible utility of a pangenomic study. Such investigation should be carefully considered in genetic counselling in female carriers to assess the risk of transmitting severe HA with a "contiguous gene syndrome".
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Affiliation(s)
- Y Jourdy
- Hospices Civils de Lyon, Hôpital Edouard Herriot, Service d'hématologie Biologique, Lyon, France.,Univ Lyon, EA 4609 Hémostase et cancer, Université Claude Bernard Lyon 1, Lyon, France
| | - N Chatron
- Hospices Civils de Lyon, Groupe Hospitalier Est, Laboratoire de Cytogénétique Constitutionnelle, Bron, France.,Univ Lyon, CRNL, équipe GENDEV INSERM U1028, CNRS UMR5292, Université Claude Bernard Lyon 1, Lyon, France
| | - M Fretigny
- Hospices Civils de Lyon, Hôpital Edouard Herriot, Service d'hématologie Biologique, Lyon, France
| | - M L Carage
- Hospices Civils de Lyon, Hôpital Edouard Herriot, Service d'hématologie Biologique, Lyon, France
| | - H Chambost
- Centre de traitement de l'hémophilie, CHU La Timone, Marseille, France
| | | | - V Roussel-Robert
- Centre de traitement de l'hémophilie, Hôpital Cochin, Paris, France
| | - C Negrier
- Hospices Civils de Lyon, Hôpital Edouard Herriot, Service d'hématologie Biologique, Lyon, France.,Univ Lyon, EA 4609 Hémostase et cancer, Université Claude Bernard Lyon 1, Lyon, France
| | - D Sanlaville
- Hospices Civils de Lyon, Groupe Hospitalier Est, Laboratoire de Cytogénétique Constitutionnelle, Bron, France.,Univ Lyon, CRNL, équipe GENDEV INSERM U1028, CNRS UMR5292, Université Claude Bernard Lyon 1, Lyon, France
| | - C Vinciguerra
- Hospices Civils de Lyon, Hôpital Edouard Herriot, Service d'hématologie Biologique, Lyon, France.,Univ Lyon, EA 4609 Hémostase et cancer, Université Claude Bernard Lyon 1, Lyon, France
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37
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Chen CP, Chen CY, Chern SR, Wu PS, Chen YN, Chen SW, Lee CC, Town DD, Lee MS, Yang CW, Wang W. Molecular cytogenetic characterization of Xp22.32→pter deletion and Xq26.3→qter duplication in a male fetus associated with 46,Y,rec(X)dup(Xq) inv(X)(p22.3q26.3), a hypoplastic left heart, short stature, and maternal X chromosome pericentric inversion. Taiwan J Obstet Gynecol 2017; 55:705-711. [PMID: 27751420 DOI: 10.1016/j.tjog.2016.05.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/19/2016] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE We present molecular cytogenetic characterization of an Xp22.32→pter deletion and an Xq26.3→qter duplication in a male fetus with congenital malformations and maternal X chromosome pericentric inversion. MATERIALS AND METHODS A 22-year-old woman underwent amniocentesis at 17 weeks of gestation because of an abnormal maternal serum screening result. Prenatal ultrasound revealed a hypoplastic left heart and short limbs. Amniocentesis revealed a karyotype of 46,Y,der(X) t(X;?)(p22.31;?). The pregnancy was subsequently terminated, and a malformed fetus was delivered with short stature and facial dysmorphism. Repeat amniocentesis was performed before termination of the pregnancy. Array comparative genomic hybridization was performed on uncultured amniocytes and maternal blood. Conventional cytogenetic analysis was performed on cultured amniocytes, cord blood, and blood from both parents. Fluorescence in situ hybridization was performed on cultured amniocytes. RESULTS The maternal karyotype was 46,X,inv(X)(p22.3q26.3). The fetal karyotype was 46,Y, rec(X)dup(Xq)inv(X)(p22.3q26.3) or 46,Y, rec(X)(qter→q26.3::p22.3→qter). Array comparative genomic hybridization on uncultured amniocytes revealed a 4.56-Mb deletion of Xp22.33-p22.32 encompassing SHOX, CSF2RA, and ARSE, and a 19.22-Mb duplication of Xq26.3-q28 encompassing SOX3, FMR1, MECP2, RAB39B, and CLIC2 in the fetus. The mother did not have X chromosome imbalance. CONCLUSION Detection of X chromosome aberration in a male fetus should give suspicion of a recombinant X chromosome derived from maternal X chromosome pericentric inversion.
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Affiliation(s)
- Chih-Ping Chen
- Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan; Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan; Department of Biotechnology, Asia University, Taichung, Taiwan; School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan; Institute of Clinical and Community Health Nursing, National Yang-Ming University, Taipei, Taiwan; Department of Obstetrics and Gynecology, School of Medicine, National Yang-Ming University, Taipei, Taiwan.
| | - Chen-Yu Chen
- Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan; Department of Medicine, MacKay Medical College, New Taipei City, Taiwan; MacKay Junior College of Medicine, Nursing and Management, Taipei, Taiwan
| | - Schu-Rern Chern
- Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan
| | | | - Yen-Ni Chen
- Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan
| | - Shin-Wen Chen
- Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan
| | - Chen-Chi Lee
- Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan
| | - Dai-Dyi Town
- Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan
| | - Meng-Shan Lee
- Department of Obstetrics and Gynecology, MacKay Memorial Hospital, Taipei, Taiwan
| | - Chien-Wen Yang
- Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan
| | - Wayseen Wang
- Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan; Department of Bioengineering, Tatung University, Taipei, Taiwan
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38
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Abstract
Neurons are highly polarized cells that exhibit one of the more complex morphology and function. Neuronal intracellular trafficking plays a key role in dictating the directionality and specificity of vesicle formation, transport and fusion, allowing the transmission of information in sophisticate cellular network. Thus, the integrity of protein trafficking and spatial organization is especially important in neuronal cells. RAB proteins, small monomeric GTPases belonging to the RAS superfamily, spatially and temporally orchestrate specific vesicular trafficking steps. In this review we summarise the known roles of RAB GTPases involved in the maintenance of neuronal vesicular trafficking in the central nervous system. In particular, we discriminate the axonal pre-synaptic trafficking and dendritic post-synaptic trafficking, to better underlie how a correct orchestration of vesicle movement is necessary to maintain neuronal polarity and then, to permit an accurate architecture and functionality of synaptic activity.
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Affiliation(s)
- Maria Lidia Mignogna
- a Molecular Genetics of Intellectual Disabilities Unit, Division of Neuroscience at IRCCS San Raffaele Scientific Institute , Milan , Italy
| | - Patrizia D'Adamo
- a Molecular Genetics of Intellectual Disabilities Unit, Division of Neuroscience at IRCCS San Raffaele Scientific Institute , Milan , Italy
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39
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Tang BL. Rabs, Membrane Dynamics, and Parkinson's Disease. J Cell Physiol 2016; 232:1626-1633. [DOI: 10.1002/jcp.25713] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 11/29/2016] [Indexed: 12/18/2022]
Affiliation(s)
- Bor Luen Tang
- Department of Biochemistry, Yong Loo Lin School of Medicine; National University of Singapore; Singapore 117597
- NUS Graduate School for Integrative Sciences and Engineering; National University of Singapore; Singapore 117456
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40
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Accurate, simple, and inexpensive assays to diagnose F8 gene inversion mutations in hemophilia A patients and carriers. Blood Adv 2016; 1:231-239. [PMID: 29296938 DOI: 10.1182/bloodadvances.2016001651] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 11/03/2016] [Indexed: 01/16/2023] Open
Abstract
The most frequent mutations resulting in hemophilia A are an intron 22 or intron 1 gene inversion, which together cause ∼50% of severe hemophilia A cases. We report a simple and accurate RNA-based assay to detect these mutations in patients and heterozygous carriers. The assays do not require specialized equipment or expensive reagents; therefore, they may provide useful and economic protocols that could be standardized for central laboratory testing. RNA is purified from a blood sample, and reverse transcription nested polymerase chain reaction (RT-NPCR) reactions amplify DNA fragments with the F8 sequence spanning the exon 22 to 23 splice site (intron 22 inversion test) or the exon 1 to 2 splice site (intron 1 inversion test). These sequences will be amplified only from F8 RNA without an intron 22 or intron 1 inversion mutation, respectively. Additional RT-NPCR reactions are then carried out to amplify the inverted sequences extending from F8 exon 19 to the first in-frame stop codon within intron 22 or a chimeric transcript containing F8 exon 1 and the VBP1 gene. These latter 2 products are produced only by individuals with an intron 22 or intron 1 inversion mutation, respectively. The intron 22 inversion mutations may be further classified (eg, as type 1 or type 2, reflecting the specific homologous recombination sites) by the standard DNA-based "inverse-shifting" PCR assay if desired. Efficient Bcl I and T4 DNA ligase enzymes that cleave and ligate DNA in minutes were used, which is a substantial improvement over previous protocols that required overnight incubations. These protocols can accurately detect F8 inversion mutations via same-day testing of patient samples.
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41
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Ha K, Shen Y, Graves T, Kim CH, Kim HG. The presence of two rare genomic syndromes, 1q21 deletion and Xq28 duplication, segregating independently in a family with intellectual disability. Mol Cytogenet 2016; 9:74. [PMID: 27708714 PMCID: PMC5041540 DOI: 10.1186/s13039-016-0286-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 09/22/2016] [Indexed: 01/21/2023] Open
Abstract
Background 1q21 microdeletion syndrome is a rare contiguous gene deletion disorder with de novo or autosomal dominant inheritance patterns and its phenotypic features include intellectual disability, distinctive facial dysmorphism, microcephaly, cardiac abnormalities, and cataracts. MECP2 duplication syndrome is an X-linked recessive neurodevelopmental disorder characterized by intellectual disability, global developmental delay, and other neurological complications including late-onset seizures. Previously, these two different genetic syndromes have not been reported segregating independently in a same family. Case presentation Here we describe two siblings carrying either a chromosome 1q21 microdeletion or a chromosome Xq28 duplication. Using a comparative genomic hybridization (CGH) array, we identified a 1.24 Mb heterozygous deletion at 1q21 resulting in the loss of 9 genes in a girl with learning disability, hypothyroidism, short stature, sensory integration disorder, and soft dysmorphic features including cupped ears and a unilateral ear pit. We also characterized a 508 kb Xq28 duplication encompassing MECP2 in her younger brother with hypotonia, poor speech, cognitive and motor impairment. The parental CGH and quantitative PCR (qPCR) analyses revealed that the 1q21 deletion in the elder sister is de novo, but the Xq28 duplication in the younger brother was originally inherited from the maternal grandmother through the mother, both of whom are asymptomatic carriers. RT-qPCR assays revealed that the affected brother has almost double the amount of MECP2 mRNA expression compared to other family members of both genders including maternal grandmother and mother who have the same Xq28 duplication with no phenotype. This suggests the X chromosome with an Xq28 duplication in the carrier females is preferentially silenced. Conclusion From our understanding, this would be the first report showing the independent segregation of two genetically unrelated syndromes, 1q21 microdeletion and Xq28 duplication, in a same family, especially in siblings. Although these two chromosomal abnormalities share some similar phenotypes such as intellectual disability, mild dysmorphic features, and cardiac abnormalities, the presence of two unrelated and rare syndromes in siblings is very unusual. Therefore, further comprehensive investigations in similar cases are required for future studies.
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Affiliation(s)
- Kyungsoo Ha
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030 USA ; Section of Reproductive Endocrinology, Infertility & Genetics, Department of Obstetrics & Gynecology, Augusta University, Augusta, GA 30912 USA
| | - Yiping Shen
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114 USA
| | - Tyler Graves
- Section of Reproductive Endocrinology, Infertility & Genetics, Department of Obstetrics & Gynecology, Augusta University, Augusta, GA 30912 USA
| | - Cheol-Hee Kim
- Department of Biology, Chungnam National University, Daejeon, 34134 South Korea
| | - Hyung-Goo Kim
- Section of Reproductive Endocrinology, Infertility & Genetics, Department of Obstetrics & Gynecology, Augusta University, Augusta, GA 30912 USA ; Department of Neuroscience and Regenerative Medicine, Augusta University, 1120 15th Street, Augusta, GA 30912 USA
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42
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Mata IF, Jang Y, Kim CH, Hanna DS, Dorschner MO, Samii A, Agarwal P, Roberts JW, Klepitskaya O, Shprecher DR, Chung KA, Factor SA, Espay AJ, Revilla FJ, Higgins DS, Litvan I, Leverenz JB, Yearout D, Inca-Martinez M, Martinez E, Thompson TR, Cholerton BA, Hu SC, Edwards KL, Kim KS, Zabetian CP. The RAB39B p.G192R mutation causes X-linked dominant Parkinson's disease. Mol Neurodegener 2015; 10:50. [PMID: 26399558 PMCID: PMC4581468 DOI: 10.1186/s13024-015-0045-4] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 09/17/2015] [Indexed: 11/10/2022] Open
Abstract
Objective To identify the causal gene in a multi-incident U.S. kindred with Parkinson’s disease (PD). Methods We characterized a family with a classical PD phenotype in which 7 individuals (5 males and 2 females) were affected with a mean age at onset of 46.1 years (range, 29-57 years). We performed whole exome sequencing on 4 affected and 1 unaffected family members. Sanger-sequencing was then used to verify and genotype all candidate variants in the remainder of the pedigree. Cultured cells transfected with wild-type or mutant constructs were used to characterize proteins of interest. Results We identified a missense mutation (c.574G > A; p.G192R) in the RAB39B gene that closely segregated with disease and exhibited X-linked dominant inheritance with reduced penetrance in females. The mutation occurred in a highly conserved amino acid residue and was not observed among 87,725 X chromosomes in the Exome Aggregation Consortium dataset. Sequencing of the RAB39B coding region in 587 familial PD cases yielded two additional mutations (c.428C > G [p.A143G] and c.624_626delGAG [p.R209del]) that were predicted to be deleterious in silico but occurred in families that were not sufficiently informative to assess segregation with disease. Experiments in PC12 and SK-N-BE(2)C cells demonstrated that p.G192R resulted in mislocalization of the mutant protein, possibly by altering the structure of the hypervariable C-terminal domain which mediates intracellular targeting. Conclusions Our findings implicate RAB39B, an essential regulator of vesicular-trafficking, in clinically typical PD. Further characterization of normal and aberrant RAB39B function might elucidate important mechanisms underlying neurodegeneration in PD and related disorders. Electronic supplementary material The online version of this article (doi:10.1186/s13024-015-0045-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ignacio F Mata
- Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA. .,Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA.
| | - Yongwoo Jang
- Molecular Neurobiology Laboratory, Department of Psychiatry and Program in Neuroscience, McLean Hospital/Harvard Medical School, Belmont, MA, USA.
| | - Chun-Hyung Kim
- Molecular Neurobiology Laboratory, Department of Psychiatry and Program in Neuroscience, McLean Hospital/Harvard Medical School, Belmont, MA, USA.
| | - David S Hanna
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA. .,Department of Pathology, University of Washington, Seattle, WA, USA.
| | - Michael O Dorschner
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA. .,Department of Pathology, University of Washington, Seattle, WA, USA.
| | - Ali Samii
- Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA. .,Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA.
| | - Pinky Agarwal
- Booth Gardner Parkinson's Care Center, Evergreen Hospital Medical Center, Kirkland, WA, USA.
| | | | | | - David R Shprecher
- Department of Neurology, University of Utah, Salt Lake City, UT, USA.
| | - Kathryn A Chung
- Parkinson's Disease Research, Education, and Clinical Center, Portland Veterans Affairs Medical Center, Portland, OR, USA. .,Department of Neurology, Oregon Health and Science University, Portland, OR, USA.
| | - Stewart A Factor
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA.
| | - Alberto J Espay
- Department of Neurology and Rehabilitation Medicine, University of Cincinnati, Cincinnati, OH, USA.
| | - Fredy J Revilla
- Division of Neurology at Greenville Health System and the University of South Carolina Medical School-Greenville, Greenville, SC, USA.
| | - Donald S Higgins
- Samuel Stratton Veterans Affairs Medical Center, Albany, NY, USA.
| | - Irene Litvan
- Movement Disorder Center, Department of Neurosciences, University of California, San Diego, CA, USA.
| | - James B Leverenz
- Lou Ruvo Center for Brain Health, Cleveland Clinic, Cleveland, OH, USA.
| | - Dora Yearout
- Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA. .,Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA.
| | - Miguel Inca-Martinez
- Neurogenetics Research Center, Instituto Nacional de Ciencias Neurologicas, Lima, Peru.
| | - Erica Martinez
- Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA. .,Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA.
| | | | - Brenna A Cholerton
- Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA. .,Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA.
| | - Shu-Ching Hu
- Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA. .,Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA.
| | - Karen L Edwards
- Department of Epidemiology, University of California, Irvine, CA, USA.
| | - Kwang-Soo Kim
- Molecular Neurobiology Laboratory, Department of Psychiatry and Program in Neuroscience, McLean Hospital/Harvard Medical School, Belmont, MA, USA.
| | - Cyrus P Zabetian
- Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA. .,Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA.
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Magini P, Poscente M, Ferrari S, Vargiolu M, Bacchelli E, Graziano C, Wischmeijer A, Turchetti D, Malaspina E, Marchiani V, Cordelli DM, Franzoni E, Romeo G, Seri M. Cytogenetic and molecular characterization of a recombinant X chromosome in a family with a severe neurologic phenotype and macular degeneration. Mol Cytogenet 2015; 8:58. [PMID: 26236399 PMCID: PMC4522089 DOI: 10.1186/s13039-015-0164-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 07/15/2015] [Indexed: 11/13/2022] Open
Abstract
Background Duplications of MECP2 gene in males cause a syndrome characterized by distinctive clinical features, including severe to profound mental retardation, infantile hypotonia, mild dysmorphic features, poor speech development, autistic features, seizures, progressive spasticity and recurrent infections. Patients with complex chromosome rearrangements, leading to Xq28 duplication, share most of the clinical features of individuals with tandem duplications, in particular neurologic problems, suggesting a major pathogenetic role of MECP2 overexpression. Results We performed cytogenetic and molecular cytogenetic studies in a previously described family with affected males showing congenital ataxia, late-onset progressive myoclonic encephalopathy and selective macular degeneration. Microsatellite, FISH and array-CGH analyses identified a recombinant X chromosome with a deletion of the PAR1 region, encompassing SHOX, replaced by a duplicated segment of the Xq28 terminal portion, including MECP2. Conclusions Our report describes the identification of the actual genetic cause underlying a severe syndrome that previous preliminary analyses erroneously associated to a terminal Xp22.33 region. In the present family as well as in previously reported patients with similar rearrangements, the observed neurologic phenotype is ascribable to MECP2 duplication, with an undefined contribution of the other involved genes. Maculopathy, presented by affected males reported here, could be a novel clinical feature associated to Xq28 disomy due to recombinant X chromosomes, but at present the underlying pathogenetic mechanism is unknown and this potential clinical correlation should be confirmed through the collection of additional patients.
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Affiliation(s)
- Pamela Magini
- U.O. Genetica Medica, Policlinico Sant'Orsola-Malpighi, DIMEC, Università di Bologna, via Massarenti, 9, Bologna, 40138 Italy
| | - Monica Poscente
- S.S.V.D. Biologia Molecolare, Citogenetica, Citomorfologia Ematica e Vaginale, Ospedale Belcolle, Viterbo, Italy
| | - Simona Ferrari
- U.O. Genetica Medica, AOU di Bologna, Policlinico S. Orsola-Malpighi, Bologna, 40138 Italy
| | - Manuela Vargiolu
- Centro Interdipartimentale per la Ricerca Industriale Scienze della Vita e Tecnologie per la Salute, Università di Bologna, Bologna, Italy
| | - Elena Bacchelli
- Dipartimento di Farmacia e Biotecnologie, Università di Bologna, Bologna, Italy
| | - Claudio Graziano
- U.O. Genetica Medica, AOU di Bologna, Policlinico S. Orsola-Malpighi, Bologna, 40138 Italy
| | - Anita Wischmeijer
- U.O. Genetica Medica, AOU di Bologna, Policlinico S. Orsola-Malpighi, Bologna, 40138 Italy.,S.S.D. Genetica Clinica, Arcispedale S. Maria Nuova-Istituto di Ricovero e Cura a Carattere Scientifico, Reggio Emilia, Italy
| | - Daniela Turchetti
- U.O. Genetica Medica, Policlinico Sant'Orsola-Malpighi, DIMEC, Università di Bologna, via Massarenti, 9, Bologna, 40138 Italy
| | - Elisabetta Malaspina
- U.O. Neuropsichiatria Infantile, Policlinico Sant'Orsola-Malpighi, DIMEC, Università di Bologna, Bologna, Italy
| | - Valentina Marchiani
- U.O. Neuropsichiatria Infantile, Policlinico Sant'Orsola-Malpighi, DIMEC, Università di Bologna, Bologna, Italy
| | - Duccio Maria Cordelli
- U.O. Neuropsichiatria Infantile, Policlinico Sant'Orsola-Malpighi, DIMEC, Università di Bologna, Bologna, Italy
| | - Emilio Franzoni
- U.O. Neuropsichiatria Infantile, Policlinico Sant'Orsola-Malpighi, DIMEC, Università di Bologna, Bologna, Italy
| | - Giovanni Romeo
- U.O. Genetica Medica, Policlinico Sant'Orsola-Malpighi, DIMEC, Università di Bologna, via Massarenti, 9, Bologna, 40138 Italy
| | - Marco Seri
- U.O. Genetica Medica, Policlinico Sant'Orsola-Malpighi, DIMEC, Università di Bologna, via Massarenti, 9, Bologna, 40138 Italy
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Lesage S, Bras J, Cormier-Dequaire F, Condroyer C, Nicolas A, Darwent L, Guerreiro R, Majounie E, Federoff M, Heutink P, Wood NW, Gasser T, Hardy J, Tison F, Singleton A, Brice A. Loss-of-function mutations in RAB39B are associated with typical early-onset Parkinson disease. NEUROLOGY-GENETICS 2015; 1:e9. [PMID: 27066548 PMCID: PMC4821081 DOI: 10.1212/nxg.0000000000000009] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/12/2015] [Accepted: 05/19/2015] [Indexed: 11/15/2022]
Abstract
Rab proteins are small molecular weight guanosine triphosphatases involved in the regulation of vesicular trafficking.(1) Three of 4 X-linked RAB genes are specific to the brain, including RAB39B. Recently, Wilson et al.(2) reported that mutations in RAB39B cause X-linked intellectual disability (ID) and pathologically confirmed Parkinson disease (PD). They identified a ∼45-kb deletion resulting in the complete loss of RAB39B in an Australian kindred and a missense mutation in a large Wisconsin kindred. Here, we report an additional affected man with typical PD and mild mental retardation harboring a new truncating mutation in RAB39B.
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Affiliation(s)
- Suzanne Lesage
- Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS, UMR 7225, Sorbonne Universités, UPMC University Paris 06 UMR S 1127 (S.L., F.C.-D., C.C., A.N., A.B.), Paris, France; Centre d'Investigation Clinique Pitié Neurosciences CIC-1422 (F.C.-D.); AP-HP, Hôpital de la Salpêtrière (A.B.), Department of Genetics and Cytogenetics, Paris, France; Department of Molecular Neuroscience (J.B., L.D., R.G., M.F., N.W., J.H.), UCL Institute of Neurology, London, United Kingdom; Laboratory of Neurogenetics (E.M., M.F., A.S.), National Institute on Aging, Bethesda, MD; Hertie Institute for Clinical Brain Research (P.H., T.G.), University of Tübingen and DZNE (P.H., T.G.), German Center for Neurodegenerative Diseases, Tübingen, Germany; and Institut des Maladies Neurodégénératives (F.T.), Université de Bordeaux et CHU de Bordeaux, Bordeaux, France
| | - Jose Bras
- Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS, UMR 7225, Sorbonne Universités, UPMC University Paris 06 UMR S 1127 (S.L., F.C.-D., C.C., A.N., A.B.), Paris, France; Centre d'Investigation Clinique Pitié Neurosciences CIC-1422 (F.C.-D.); AP-HP, Hôpital de la Salpêtrière (A.B.), Department of Genetics and Cytogenetics, Paris, France; Department of Molecular Neuroscience (J.B., L.D., R.G., M.F., N.W., J.H.), UCL Institute of Neurology, London, United Kingdom; Laboratory of Neurogenetics (E.M., M.F., A.S.), National Institute on Aging, Bethesda, MD; Hertie Institute for Clinical Brain Research (P.H., T.G.), University of Tübingen and DZNE (P.H., T.G.), German Center for Neurodegenerative Diseases, Tübingen, Germany; and Institut des Maladies Neurodégénératives (F.T.), Université de Bordeaux et CHU de Bordeaux, Bordeaux, France
| | - Florence Cormier-Dequaire
- Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS, UMR 7225, Sorbonne Universités, UPMC University Paris 06 UMR S 1127 (S.L., F.C.-D., C.C., A.N., A.B.), Paris, France; Centre d'Investigation Clinique Pitié Neurosciences CIC-1422 (F.C.-D.); AP-HP, Hôpital de la Salpêtrière (A.B.), Department of Genetics and Cytogenetics, Paris, France; Department of Molecular Neuroscience (J.B., L.D., R.G., M.F., N.W., J.H.), UCL Institute of Neurology, London, United Kingdom; Laboratory of Neurogenetics (E.M., M.F., A.S.), National Institute on Aging, Bethesda, MD; Hertie Institute for Clinical Brain Research (P.H., T.G.), University of Tübingen and DZNE (P.H., T.G.), German Center for Neurodegenerative Diseases, Tübingen, Germany; and Institut des Maladies Neurodégénératives (F.T.), Université de Bordeaux et CHU de Bordeaux, Bordeaux, France
| | - Christel Condroyer
- Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS, UMR 7225, Sorbonne Universités, UPMC University Paris 06 UMR S 1127 (S.L., F.C.-D., C.C., A.N., A.B.), Paris, France; Centre d'Investigation Clinique Pitié Neurosciences CIC-1422 (F.C.-D.); AP-HP, Hôpital de la Salpêtrière (A.B.), Department of Genetics and Cytogenetics, Paris, France; Department of Molecular Neuroscience (J.B., L.D., R.G., M.F., N.W., J.H.), UCL Institute of Neurology, London, United Kingdom; Laboratory of Neurogenetics (E.M., M.F., A.S.), National Institute on Aging, Bethesda, MD; Hertie Institute for Clinical Brain Research (P.H., T.G.), University of Tübingen and DZNE (P.H., T.G.), German Center for Neurodegenerative Diseases, Tübingen, Germany; and Institut des Maladies Neurodégénératives (F.T.), Université de Bordeaux et CHU de Bordeaux, Bordeaux, France
| | - Aude Nicolas
- Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS, UMR 7225, Sorbonne Universités, UPMC University Paris 06 UMR S 1127 (S.L., F.C.-D., C.C., A.N., A.B.), Paris, France; Centre d'Investigation Clinique Pitié Neurosciences CIC-1422 (F.C.-D.); AP-HP, Hôpital de la Salpêtrière (A.B.), Department of Genetics and Cytogenetics, Paris, France; Department of Molecular Neuroscience (J.B., L.D., R.G., M.F., N.W., J.H.), UCL Institute of Neurology, London, United Kingdom; Laboratory of Neurogenetics (E.M., M.F., A.S.), National Institute on Aging, Bethesda, MD; Hertie Institute for Clinical Brain Research (P.H., T.G.), University of Tübingen and DZNE (P.H., T.G.), German Center for Neurodegenerative Diseases, Tübingen, Germany; and Institut des Maladies Neurodégénératives (F.T.), Université de Bordeaux et CHU de Bordeaux, Bordeaux, France
| | - Lee Darwent
- Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS, UMR 7225, Sorbonne Universités, UPMC University Paris 06 UMR S 1127 (S.L., F.C.-D., C.C., A.N., A.B.), Paris, France; Centre d'Investigation Clinique Pitié Neurosciences CIC-1422 (F.C.-D.); AP-HP, Hôpital de la Salpêtrière (A.B.), Department of Genetics and Cytogenetics, Paris, France; Department of Molecular Neuroscience (J.B., L.D., R.G., M.F., N.W., J.H.), UCL Institute of Neurology, London, United Kingdom; Laboratory of Neurogenetics (E.M., M.F., A.S.), National Institute on Aging, Bethesda, MD; Hertie Institute for Clinical Brain Research (P.H., T.G.), University of Tübingen and DZNE (P.H., T.G.), German Center for Neurodegenerative Diseases, Tübingen, Germany; and Institut des Maladies Neurodégénératives (F.T.), Université de Bordeaux et CHU de Bordeaux, Bordeaux, France
| | - Rita Guerreiro
- Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS, UMR 7225, Sorbonne Universités, UPMC University Paris 06 UMR S 1127 (S.L., F.C.-D., C.C., A.N., A.B.), Paris, France; Centre d'Investigation Clinique Pitié Neurosciences CIC-1422 (F.C.-D.); AP-HP, Hôpital de la Salpêtrière (A.B.), Department of Genetics and Cytogenetics, Paris, France; Department of Molecular Neuroscience (J.B., L.D., R.G., M.F., N.W., J.H.), UCL Institute of Neurology, London, United Kingdom; Laboratory of Neurogenetics (E.M., M.F., A.S.), National Institute on Aging, Bethesda, MD; Hertie Institute for Clinical Brain Research (P.H., T.G.), University of Tübingen and DZNE (P.H., T.G.), German Center for Neurodegenerative Diseases, Tübingen, Germany; and Institut des Maladies Neurodégénératives (F.T.), Université de Bordeaux et CHU de Bordeaux, Bordeaux, France
| | - Elisa Majounie
- Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS, UMR 7225, Sorbonne Universités, UPMC University Paris 06 UMR S 1127 (S.L., F.C.-D., C.C., A.N., A.B.), Paris, France; Centre d'Investigation Clinique Pitié Neurosciences CIC-1422 (F.C.-D.); AP-HP, Hôpital de la Salpêtrière (A.B.), Department of Genetics and Cytogenetics, Paris, France; Department of Molecular Neuroscience (J.B., L.D., R.G., M.F., N.W., J.H.), UCL Institute of Neurology, London, United Kingdom; Laboratory of Neurogenetics (E.M., M.F., A.S.), National Institute on Aging, Bethesda, MD; Hertie Institute for Clinical Brain Research (P.H., T.G.), University of Tübingen and DZNE (P.H., T.G.), German Center for Neurodegenerative Diseases, Tübingen, Germany; and Institut des Maladies Neurodégénératives (F.T.), Université de Bordeaux et CHU de Bordeaux, Bordeaux, France
| | - Monica Federoff
- Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS, UMR 7225, Sorbonne Universités, UPMC University Paris 06 UMR S 1127 (S.L., F.C.-D., C.C., A.N., A.B.), Paris, France; Centre d'Investigation Clinique Pitié Neurosciences CIC-1422 (F.C.-D.); AP-HP, Hôpital de la Salpêtrière (A.B.), Department of Genetics and Cytogenetics, Paris, France; Department of Molecular Neuroscience (J.B., L.D., R.G., M.F., N.W., J.H.), UCL Institute of Neurology, London, United Kingdom; Laboratory of Neurogenetics (E.M., M.F., A.S.), National Institute on Aging, Bethesda, MD; Hertie Institute for Clinical Brain Research (P.H., T.G.), University of Tübingen and DZNE (P.H., T.G.), German Center for Neurodegenerative Diseases, Tübingen, Germany; and Institut des Maladies Neurodégénératives (F.T.), Université de Bordeaux et CHU de Bordeaux, Bordeaux, France
| | - Peter Heutink
- Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS, UMR 7225, Sorbonne Universités, UPMC University Paris 06 UMR S 1127 (S.L., F.C.-D., C.C., A.N., A.B.), Paris, France; Centre d'Investigation Clinique Pitié Neurosciences CIC-1422 (F.C.-D.); AP-HP, Hôpital de la Salpêtrière (A.B.), Department of Genetics and Cytogenetics, Paris, France; Department of Molecular Neuroscience (J.B., L.D., R.G., M.F., N.W., J.H.), UCL Institute of Neurology, London, United Kingdom; Laboratory of Neurogenetics (E.M., M.F., A.S.), National Institute on Aging, Bethesda, MD; Hertie Institute for Clinical Brain Research (P.H., T.G.), University of Tübingen and DZNE (P.H., T.G.), German Center for Neurodegenerative Diseases, Tübingen, Germany; and Institut des Maladies Neurodégénératives (F.T.), Université de Bordeaux et CHU de Bordeaux, Bordeaux, France
| | - Nicholas W Wood
- Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS, UMR 7225, Sorbonne Universités, UPMC University Paris 06 UMR S 1127 (S.L., F.C.-D., C.C., A.N., A.B.), Paris, France; Centre d'Investigation Clinique Pitié Neurosciences CIC-1422 (F.C.-D.); AP-HP, Hôpital de la Salpêtrière (A.B.), Department of Genetics and Cytogenetics, Paris, France; Department of Molecular Neuroscience (J.B., L.D., R.G., M.F., N.W., J.H.), UCL Institute of Neurology, London, United Kingdom; Laboratory of Neurogenetics (E.M., M.F., A.S.), National Institute on Aging, Bethesda, MD; Hertie Institute for Clinical Brain Research (P.H., T.G.), University of Tübingen and DZNE (P.H., T.G.), German Center for Neurodegenerative Diseases, Tübingen, Germany; and Institut des Maladies Neurodégénératives (F.T.), Université de Bordeaux et CHU de Bordeaux, Bordeaux, France
| | - Thomas Gasser
- Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS, UMR 7225, Sorbonne Universités, UPMC University Paris 06 UMR S 1127 (S.L., F.C.-D., C.C., A.N., A.B.), Paris, France; Centre d'Investigation Clinique Pitié Neurosciences CIC-1422 (F.C.-D.); AP-HP, Hôpital de la Salpêtrière (A.B.), Department of Genetics and Cytogenetics, Paris, France; Department of Molecular Neuroscience (J.B., L.D., R.G., M.F., N.W., J.H.), UCL Institute of Neurology, London, United Kingdom; Laboratory of Neurogenetics (E.M., M.F., A.S.), National Institute on Aging, Bethesda, MD; Hertie Institute for Clinical Brain Research (P.H., T.G.), University of Tübingen and DZNE (P.H., T.G.), German Center for Neurodegenerative Diseases, Tübingen, Germany; and Institut des Maladies Neurodégénératives (F.T.), Université de Bordeaux et CHU de Bordeaux, Bordeaux, France
| | - John Hardy
- Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS, UMR 7225, Sorbonne Universités, UPMC University Paris 06 UMR S 1127 (S.L., F.C.-D., C.C., A.N., A.B.), Paris, France; Centre d'Investigation Clinique Pitié Neurosciences CIC-1422 (F.C.-D.); AP-HP, Hôpital de la Salpêtrière (A.B.), Department of Genetics and Cytogenetics, Paris, France; Department of Molecular Neuroscience (J.B., L.D., R.G., M.F., N.W., J.H.), UCL Institute of Neurology, London, United Kingdom; Laboratory of Neurogenetics (E.M., M.F., A.S.), National Institute on Aging, Bethesda, MD; Hertie Institute for Clinical Brain Research (P.H., T.G.), University of Tübingen and DZNE (P.H., T.G.), German Center for Neurodegenerative Diseases, Tübingen, Germany; and Institut des Maladies Neurodégénératives (F.T.), Université de Bordeaux et CHU de Bordeaux, Bordeaux, France
| | - François Tison
- Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS, UMR 7225, Sorbonne Universités, UPMC University Paris 06 UMR S 1127 (S.L., F.C.-D., C.C., A.N., A.B.), Paris, France; Centre d'Investigation Clinique Pitié Neurosciences CIC-1422 (F.C.-D.); AP-HP, Hôpital de la Salpêtrière (A.B.), Department of Genetics and Cytogenetics, Paris, France; Department of Molecular Neuroscience (J.B., L.D., R.G., M.F., N.W., J.H.), UCL Institute of Neurology, London, United Kingdom; Laboratory of Neurogenetics (E.M., M.F., A.S.), National Institute on Aging, Bethesda, MD; Hertie Institute for Clinical Brain Research (P.H., T.G.), University of Tübingen and DZNE (P.H., T.G.), German Center for Neurodegenerative Diseases, Tübingen, Germany; and Institut des Maladies Neurodégénératives (F.T.), Université de Bordeaux et CHU de Bordeaux, Bordeaux, France
| | - Andrew Singleton
- Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS, UMR 7225, Sorbonne Universités, UPMC University Paris 06 UMR S 1127 (S.L., F.C.-D., C.C., A.N., A.B.), Paris, France; Centre d'Investigation Clinique Pitié Neurosciences CIC-1422 (F.C.-D.); AP-HP, Hôpital de la Salpêtrière (A.B.), Department of Genetics and Cytogenetics, Paris, France; Department of Molecular Neuroscience (J.B., L.D., R.G., M.F., N.W., J.H.), UCL Institute of Neurology, London, United Kingdom; Laboratory of Neurogenetics (E.M., M.F., A.S.), National Institute on Aging, Bethesda, MD; Hertie Institute for Clinical Brain Research (P.H., T.G.), University of Tübingen and DZNE (P.H., T.G.), German Center for Neurodegenerative Diseases, Tübingen, Germany; and Institut des Maladies Neurodégénératives (F.T.), Université de Bordeaux et CHU de Bordeaux, Bordeaux, France
| | - Alexis Brice
- Institut du Cerveau et de la Moelle épinière, ICM, Inserm U 1127, CNRS, UMR 7225, Sorbonne Universités, UPMC University Paris 06 UMR S 1127 (S.L., F.C.-D., C.C., A.N., A.B.), Paris, France; Centre d'Investigation Clinique Pitié Neurosciences CIC-1422 (F.C.-D.); AP-HP, Hôpital de la Salpêtrière (A.B.), Department of Genetics and Cytogenetics, Paris, France; Department of Molecular Neuroscience (J.B., L.D., R.G., M.F., N.W., J.H.), UCL Institute of Neurology, London, United Kingdom; Laboratory of Neurogenetics (E.M., M.F., A.S.), National Institute on Aging, Bethesda, MD; Hertie Institute for Clinical Brain Research (P.H., T.G.), University of Tübingen and DZNE (P.H., T.G.), German Center for Neurodegenerative Diseases, Tübingen, Germany; and Institut des Maladies Neurodégénératives (F.T.), Université de Bordeaux et CHU de Bordeaux, Bordeaux, France
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Mignogna ML, Giannandrea M, Gurgone A, Fanelli F, Raimondi F, Mapelli L, Bassani S, Fang H, Van Anken E, Alessio M, Passafaro M, Gatti S, Esteban JA, Huganir R, D'Adamo P. The intellectual disability protein RAB39B selectively regulates GluA2 trafficking to determine synaptic AMPAR composition. Nat Commun 2015; 6:6504. [PMID: 25784538 PMCID: PMC4383008 DOI: 10.1038/ncomms7504] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 02/03/2015] [Indexed: 01/31/2023] Open
Abstract
RAB39B is a member of the RAB family of small GTPases that controls intracellular vesicular trafficking in a compartment-specific manner. Mutations in the RAB39B gene cause intellectual disability comorbid with autism spectrum disorder and epilepsy, but the impact of RAB39B loss of function on synaptic activity is largely unexplained. Here we show that protein interacting with C-kinase 1 (PICK1) is a downstream effector of GTP-bound RAB39B and that RAB39B-PICK1 controls trafficking from the endoplasmic reticulum to the Golgi and, hence, surface expression of GluA2, a subunit of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs). The role of AMPARs in synaptic transmission varies depending on the combination of subunits (GluA1, GluA2 and GluA3) they incorporate. RAB39B downregulation in mouse hippocampal neurons skews AMPAR composition towards non GluA2-containing Ca2+-permeable forms and thereby alters synaptic activity, specifically in hippocampal neurons. We posit that the resulting alteration in synaptic function underlies cognitive dysfunction in RAB39B-related disorders. Mutations in the RAB39B gene, which encodes a protein involved in vesicular trafficking, are associated with intellectual disability, but the impact of RAB39B loss of function on synaptic activity is not known. Here the authors show that RAB39B interacts with PICK1, and that this interaction is critical for the translocation of AMPA receptor subunits into the Golgi.
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Affiliation(s)
- Maria Lidia Mignogna
- 1] Dulbecco Telethon Institute at IRCCS San Raffaele Scientific Institute, Division of Neuroscience, 20132 Milan, Italy [2] F. Hoffmann-La Roche AG, pRED Pharma Research &Early Development, DTA Neuroscience, CH4070 Basel, Switzerland [3] Vita-Salute San Raffaele University, 20132 Milan, Italy
| | - Maila Giannandrea
- 1] Dulbecco Telethon Institute at IRCCS San Raffaele Scientific Institute, Division of Neuroscience, 20132 Milan, Italy [2] F. Hoffmann-La Roche AG, pRED Pharma Research &Early Development, DTA Neuroscience, CH4070 Basel, Switzerland
| | - Antonia Gurgone
- 1] Dulbecco Telethon Institute at IRCCS San Raffaele Scientific Institute, Division of Neuroscience, 20132 Milan, Italy [2] Vita-Salute San Raffaele University, 20132 Milan, Italy
| | - Francesca Fanelli
- Department of Life Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Francesco Raimondi
- Department of Life Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Lisa Mapelli
- CNR Institute of Neuroscience, Department of BIOMETRA, University of Milan, 20129 Milan, Italy
| | - Silvia Bassani
- CNR Institute of Neuroscience, Department of BIOMETRA, University of Milan, 20129 Milan, Italy
| | - Huaqiang Fang
- Department of Neuroscience and Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | - Eelco Van Anken
- IRCCS San Raffaele Scientific Institute, Division of Genetics and Cell Biology, 20132 Milan, Italy
| | - Massimo Alessio
- IRCCS San Raffaele Scientific Institute, Division of Genetics and Cell Biology, 20132 Milan, Italy
| | - Maria Passafaro
- CNR Institute of Neuroscience, Department of BIOMETRA, University of Milan, 20129 Milan, Italy
| | - Silvia Gatti
- F. Hoffmann-La Roche AG, pRED Pharma Research &Early Development, DTA Neuroscience, CH4070 Basel, Switzerland
| | - José A Esteban
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas/Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - Richard Huganir
- Department of Neuroscience and Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | - Patrizia D'Adamo
- Dulbecco Telethon Institute at IRCCS San Raffaele Scientific Institute, Division of Neuroscience, 20132 Milan, Italy
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El-Hattab AW, Schaaf CP, Fang P, Roeder E, Kimonis VE, Church JA, Patel A, Cheung SW. Clinical characterization of int22h1/int22h2-mediated Xq28 duplication/deletion: new cases and literature review. BMC MEDICAL GENETICS 2015; 16:12. [PMID: 25927380 PMCID: PMC4422130 DOI: 10.1186/s12881-015-0157-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 02/18/2015] [Indexed: 12/21/2022]
Abstract
Background Int22h1/int22h2-mediated Xq28 duplication syndrome is caused by ~0.5 Mb chromosomal duplications mediated by nonallelic homologous recombination between intron 22 homologous region 1 (int22h1) and 2 (int22h2), which, in addition to int22h3, are also responsible for inversions disrupting the F8 gene in hemophilia A. This syndrome has recently been described in 9 males with cognitive impairment, behavioral problems, and distinctive facial features; and 6 females with milder phenotypes. The reciprocal deletion was previously reported in a mother and daughter. It was suggested that this deletion may not have phenotypic effects in females because of skewed chromosome X inactivation, but may be embryonic lethal in males. Methods Array comparative genomic hybridization analyses were performed using oligonucleotide-based chromosomal microarray. Chromosome X inactivation studies were performed at the AR (androgen receptor) and FMR1 (fragile X mental retardation 1) loci. Results We present here 5 males and 6 females with int22h1/int22h2-mediated Xq28 duplication syndrome. The males manifested cognitive impairment, behavioral problems, and distinctive facial features. Two of the six females manifested mild cognitive impairment. This duplication was maternally inherited, and skewed chromosome X inactivation was observed in the majority of females carrying the duplication. We also report the reciprocal deletion in a mother and daughter with overweight, but normal cognition. In addition, we present the first case of a prenatally diagnosed de novo int22h1/int22h2-mediated deletion in a healthy female infant. We reviewed individuals previously reported with similar or overlapping rearrangements and evaluated the potential roles of genes in the rearrangement region. Conclusions The similarity of clinical features among individuals with the int22h1/int22h2-mediated Xq28 duplication supports the notion that this duplication causes a recognizable syndrome that affects males with females exhibiting milder phenotypes. It is suggested that the observed cognitive impairment in this syndrome results from increased dosage of RAB39B gene located within the duplicated region. Increased dosage of CLIC2 may also contribute to the phenotype. The reciprocal deletion results in skewed chromosome X inactivation and no clinical phenotype in females. Review of overlapping deletions suggests that hemizygous loss of VBP1 may be the cause for the proposed male lethality associated with this deletion.
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Affiliation(s)
- Ayman W El-Hattab
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, MS NAB 2015, Houston, TX, 77030, U.S.A. .,Division of Clinical Genetics and Metabolic Disorders, Department of Pediatrics, Tawam Hospital, Al-Ain, United Arab Emirates.
| | - Christian P Schaaf
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, MS NAB 2015, Houston, TX, 77030, U.S.A. .,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA.
| | - Ping Fang
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, MS NAB 2015, Houston, TX, 77030, U.S.A.
| | - Elizabeth Roeder
- Section of Genetics, Department of Pediatrics, Baylor College of Medicine, Children's Hospital of San Antonio, San Antonio, TX, USA.
| | - Virginia E Kimonis
- Division of Genetics and Genomics, Department of Pediatrics, University of California, Irvine Medical Center, Orange, CA, USA.
| | - Joseph A Church
- Division of Clinical Immunology and Allergy, Children's Hospital Los Angeles, and Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
| | - Ankita Patel
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, MS NAB 2015, Houston, TX, 77030, U.S.A.
| | - Sau Wai Cheung
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, MS NAB 2015, Houston, TX, 77030, U.S.A.
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Wilson GR, Sim JCH, McLean C, Giannandrea M, Galea CA, Riseley JR, Stephenson SEM, Fitzpatrick E, Haas SA, Pope K, Hogan KJ, Gregg RG, Bromhead CJ, Wargowski DS, Lawrence CH, James PA, Churchyard A, Gao Y, Phelan DG, Gillies G, Salce N, Stanford L, Marsh APL, Mignogna ML, Hayflick SJ, Leventer RJ, Delatycki MB, Mellick GD, Kalscheuer VM, D'Adamo P, Bahlo M, Amor DJ, Lockhart PJ. Mutations in RAB39B cause X-linked intellectual disability and early-onset Parkinson disease with α-synuclein pathology. Am J Hum Genet 2014; 95:729-35. [PMID: 25434005 DOI: 10.1016/j.ajhg.2014.10.015] [Citation(s) in RCA: 184] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 10/30/2014] [Indexed: 11/18/2022] Open
Abstract
Advances in understanding the etiology of Parkinson disease have been driven by the identification of causative mutations in families. Genetic analysis of an Australian family with three males displaying clinical features of early-onset parkinsonism and intellectual disability identified a ∼45 kb deletion resulting in the complete loss of RAB39B. We subsequently identified a missense mutation (c.503C>A [p.Thr168Lys]) in RAB39B in an unrelated Wisconsin kindred affected by a similar clinical phenotype. In silico and in vitro studies demonstrated that the mutation destabilized the protein, consistent with loss of function. In vitro small-hairpin-RNA-mediated knockdown of Rab39b resulted in a reduction in the density of α-synuclein immunoreactive puncta in dendritic processes of cultured neurons. In addition, in multiple cell models, we demonstrated that knockdown of Rab39b was associated with reduced steady-state levels of α-synuclein. Post mortem studies demonstrated that loss of RAB39B resulted in pathologically confirmed Parkinson disease. There was extensive dopaminergic neuron loss in the substantia nigra and widespread classic Lewy body pathology. Additional pathological features included cortical Lewy bodies, brain iron accumulation, tau immunoreactivity, and axonal spheroids. Overall, we have shown that loss-of-function mutations in RAB39B cause intellectual disability and pathologically confirmed early-onset Parkinson disease. The loss of RAB39B results in dysregulation of α-synuclein homeostasis and a spectrum of neuropathological features that implicate RAB39B in the pathogenesis of Parkinson disease and potentially other neurodegenerative disorders.
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Affiliation(s)
- Gabrielle R Wilson
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Melbourne, VIC 3052, Australia; Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
| | - Joe C H Sim
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Melbourne, VIC 3052, Australia
| | - Catriona McLean
- Anatomical Pathology, The Alfred, Melbourne, VIC 3181, Australia; Australian Brain Bank Network, National Neuroscience Facility, Melbourne, VIC 3053, Australia
| | - Maila Giannandrea
- Dulbecco Telethon Institute at Division of Neuroscience, San Raffaele Scientific Institute, Milan 20132, Italy; Pharmaceutical Research and Early Development, Neuroscience, Ophthalmology, and Rare Diseases, F. Hoffmann-La Roche, Grenzacherstrasse 124, Basel 4070, Switzerland
| | - Charles A Galea
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC 3052, Australia
| | - Jessica R Riseley
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Melbourne, VIC 3052, Australia
| | - Sarah E M Stephenson
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Melbourne, VIC 3052, Australia; Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
| | - Elizabeth Fitzpatrick
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Melbourne, VIC 3052, Australia
| | - Stefan A Haas
- Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Ihnestrasse 73, Berlin 14195, Germany
| | - Kate Pope
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Melbourne, VIC 3052, Australia
| | - Kirk J Hogan
- Department of Anesthesiology, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53792, USA
| | - Ronald G Gregg
- Department of Biochemistry and Molecular Biology, Center for Genetics and Molecular Medicine, University of Louisville, Louisville, KY 40202, USA
| | - Catherine J Bromhead
- Bioinformatics Division, Walter and Eliza Hall Institute, Melbourne, VIC 3052, Australia
| | - David S Wargowski
- Waisman Center, Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Christopher H Lawrence
- Office of the State Forensic Pathologist, Royal Hobart Hospital, Hobart, TAS 7000, Australia
| | - Paul A James
- Genetic Medicine Department, Royal Melbourne Hospital, Melbourne, VIC 3050, Australia
| | - Andrew Churchyard
- Department of Neurology, Monash Children's Hospital, Melbourne, VIC 3168, Australia
| | - Yujing Gao
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Melbourne, VIC 3052, Australia
| | - Dean G Phelan
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Melbourne, VIC 3052, Australia; Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
| | - Greta Gillies
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Melbourne, VIC 3052, Australia
| | - Nicholas Salce
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Melbourne, VIC 3052, Australia
| | - Lynn Stanford
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR 97239-3098, USA
| | - Ashley P L Marsh
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Melbourne, VIC 3052, Australia; Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
| | - Maria L Mignogna
- Dulbecco Telethon Institute at Division of Neuroscience, San Raffaele Scientific Institute, Milan 20132, Italy; Pharmaceutical Research and Early Development, Neuroscience, Ophthalmology, and Rare Diseases, F. Hoffmann-La Roche, Grenzacherstrasse 124, Basel 4070, Switzerland
| | - Susan J Hayflick
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR 97239-3098, USA
| | - Richard J Leventer
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Melbourne, VIC 3052, Australia; Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia; Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, VIC 3052, Australia; Department of Neurology, Royal Children's Hospital, Melbourne, VIC 3052, Australia
| | - Martin B Delatycki
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Melbourne, VIC 3052, Australia; Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia; Clinical Genetics, Austin Health, Melbourne, VIC 3084, Australia
| | - George D Mellick
- Eskitis Institute for Drug Discovery, Griffith University, Nathan, QLD 4111, Australia
| | - Vera M Kalscheuer
- Department of Human Molecular Genetics, Max Planck Institute for Molecular Genetics, Ihnestrasse 73, Berlin 14195, Germany
| | - Patrizia D'Adamo
- Dulbecco Telethon Institute at Division of Neuroscience, San Raffaele Scientific Institute, Milan 20132, Italy
| | - Melanie Bahlo
- Bioinformatics Division, Walter and Eliza Hall Institute, Melbourne, VIC 3052, Australia; Department of Mathematics and Statistics, University of Melbourne, Melbourne, VIC 3010, Australia; Department of Medical Biology, University of Melbourne, Melbourne, VIC 3010, Australia
| | - David J Amor
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Melbourne, VIC 3052, Australia; Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
| | - Paul J Lockhart
- Bruce Lefroy Centre for Genetic Health Research, Murdoch Childrens Research Institute, Melbourne, VIC 3052, Australia; Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia.
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Clinical impacts of genomic copy number gains at Xq28. Hum Genome Var 2014; 1:14001. [PMID: 27081496 PMCID: PMC4785515 DOI: 10.1038/hgv.2014.1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Revised: 05/23/2014] [Accepted: 05/26/2014] [Indexed: 11/09/2022] Open
Abstract
Duplications of the Xq28 region are the most frequent chromosomal aberrations observed in patients with intellectual disability (ID), especially in males. These duplications occur by variable mechanisms, including interstitial duplications mediated by segmental duplications in this region and terminal duplications (functional disomy) derived from translocation with other chromosomes. The most commonly duplicated region includes methyl CpG-binding protein 2 gene (MECP2), which has a minimal duplicated size of 0.2 Mb. Patients with MECP2 duplications show severe ID, intractable seizures and recurrent infections. Duplications in the telomeric neighboring regions, which include GDP dissociation inhibitor 1 gene (GDI1) and ras-associated protein RAB39B gene (RAB39B), are independently associated with ID, and many segmental duplications located in this region could mediate these frequently observed interstitial duplications. In addition, large duplications, including MECP2 and GDI1, induce hypoplasia of the corpus callosum. Abnormalities observed in the white matter, revealed by brain magnetic resonance imaging, are a common finding in patients with MECP2 duplications. As primary sequence analysis cannot be used to determine the region responsible for chromosomal duplication syndrome, finding this region relies on the collection of genotype-phenotype data from patients.
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Andersen EF, Baldwin EE, Ellingwood S, Smith R, Lamb AN. Xq28 duplication overlapping the int22h-1/int22h-2 region and including RAB39B and CLIC2 in a family with intellectual and developmental disability. Am J Med Genet A 2014; 164A:1795-801. [PMID: 24700761 DOI: 10.1002/ajmg.a.36524] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 02/13/2014] [Indexed: 11/08/2022]
Abstract
Duplications involving terminal Xq28 are a known cause of intellectual disability (ID) in males and in females with unfavorable X-inactivation patterns. Within Xq28, functional disomy of MECP2 causes a severe ID syndrome, however the dosage sensitivity of other Xq28 duplicated genes is less certain. Duplications involving the int22h-1/int22h-2 LCR-flanked region in distal Xq28 have recently been linked to a novel ID-associated phenotype. While evidence for the dosage sensitivity of this region is emerging, the phenotypic contribution of individual genes within the int22h-1/int22h-2-flanked region has yet to be determined. We report a familial case of a novel 774 kb Xq28-qter duplication, detected by cytogenomic microarray analysis, that partially overlaps the int22h-1/int22h-2-flanked region. This duplication and a 570 kb Xpter-p22.33 loss within the pseudoautosomal region were identified in three siblings, one female and two males, who presented with developmental delays/intellectual disability, mild dysmorphic features and short stature. Although unconfirmed, these results are suggestive of maternal inheritance of a recombinant X. We compare our clinical findings to patients with int22h-1/int22h-2-mediated duplications and discuss the potential pathogenicity of genes within the duplicated region, including those within the shared region of overlap, RAB39B and CLIC2.
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Affiliation(s)
- Erica F Andersen
- Cytogenetics and Genomic Microarray, ARUP Laboratories, Salt Lake City, Utah; Department of Pathology, University of Utah, Salt Lake City, Utah
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