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Tanaka T, Chung HL. Exploiting fly models to investigate rare human neurological disorders. Neural Regen Res 2025; 20:21-28. [PMID: 38767473 PMCID: PMC11246155 DOI: 10.4103/nrr.nrr-d-23-01847] [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: 11/09/2023] [Revised: 02/05/2024] [Accepted: 03/02/2024] [Indexed: 05/22/2024] Open
Abstract
Rare neurological diseases, while individually are rare, collectively impact millions globally, leading to diverse and often severe neurological symptoms. Often attributed to genetic mutations that disrupt protein function or structure, understanding their genetic basis is crucial for accurate diagnosis and targeted therapies. To investigate the underlying pathogenesis of these conditions, researchers often use non-mammalian model organisms, such as Drosophila (fruit flies), which is valued for their genetic manipulability, cost-efficiency, and preservation of genes and biological functions across evolutionary time. Genetic tools available in Drosophila, including CRISPR-Cas9, offer a means to manipulate gene expression, allowing for a deep exploration of the genetic underpinnings of rare neurological diseases. Drosophila boasts a versatile genetic toolkit, rapid generation turnover, and ease of large-scale experimentation, making it an invaluable resource for identifying potential drug candidates. Researchers can expose flies carrying disease-associated mutations to various compounds, rapidly pinpointing promising therapeutic agents for further investigation in mammalian models and, ultimately, clinical trials. In this comprehensive review, we explore rare neurological diseases where fly research has significantly contributed to our understanding of their genetic basis, pathophysiology, and potential therapeutic implications. We discuss rare diseases associated with both neuron-expressed and glial-expressed genes. Specific cases include mutations in CDK19 resulting in epilepsy and developmental delay, mutations in TIAM1 leading to a neurodevelopmental disorder with seizures and language delay, and mutations in IRF2BPL causing seizures, a neurodevelopmental disorder with regression, loss of speech, and abnormal movements. And we explore mutations in EMC1 related to cerebellar atrophy, visual impairment, psychomotor retardation, and gain-of-function mutations in ACOX1 causing Mitchell syndrome. Loss-of-function mutations in ACOX1 result in ACOX1 deficiency, characterized by very-long-chain fatty acid accumulation and glial degeneration. Notably, this review highlights how modeling these diseases in Drosophila has provided valuable insights into their pathophysiology, offering a platform for the rapid identification of potential therapeutic interventions. Rare neurological diseases involve a wide range of expression systems, and sometimes common phenotypes can be found among different genes that cause abnormalities in neurons or glia. Furthermore, mutations within the same gene may result in varying functional outcomes, such as complete loss of function, partial loss of function, or gain-of-function mutations. The phenotypes observed in patients can differ significantly, underscoring the complexity of these conditions. In conclusion, Drosophila represents an indispensable and cost-effective tool for investigating rare neurological diseases. By facilitating the modeling of these conditions, Drosophila contributes to a deeper understanding of their genetic basis, pathophysiology, and potential therapies. This approach accelerates the discovery of promising drug candidates, ultimately benefiting patients affected by these complex and understudied diseases.
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Affiliation(s)
- Tomomi Tanaka
- Department of Neurology, Houston Methodist Research Institute, Houston, TX, USA
| | - Hyung-Lok Chung
- Department of Neurology, Houston Methodist Research Institute, Houston, TX, USA
- Department of Neurology, Weill Cornell Medical College, New York, NY, USA
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Alzayed NT, Alzuabi AH, Alqusaimi RA, El-Anany EA, Alholle A, Aboelanine AH, Omar S, Alsafi R, Elmonairy AA, Alali FJ, Alahmad A, Alsharhan H, Albash B, Marafi D. Tribal Founder EMC1 Variant in 5 Kuwaiti Families Expands Phenotypic Spectrum of EMC1-Related Disorder. Neurol Genet 2024; 10:e200156. [PMID: 38784058 PMCID: PMC11115761 DOI: 10.1212/nxg.0000000000200156] [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: 01/16/2024] [Accepted: 03/18/2024] [Indexed: 05/25/2024]
Abstract
Background and Objectives The endoplasmic reticulum (ER) membrane protein complex is a conserved multisubunit transmembrane complex that enables energy-independent insertion of newly synthesized membrane proteins into ER membranes, mediating protein folding, phospholipid transfer from ER to mitochondria, and elimination of misfolded proteins. The first subunit of EMC (EMC1) is encoded by EMC1. Both monoallelic de novo and biallelic EMC1 variants have been identified to cause cerebellar atrophy, visual impairment, and psychomotor retardation (CAVIPMR) [OMIM #616875]. Eight families with biallelic EMC1 variants and CAVIPMR have been reported. Here, we describe 8 individuals from 5 Kuwaiti families from the same tribe, with the previously reported homozygous pathogenic missense EMC1 variant [c.245C>T:p.(Thr82Met)] and CAVIPMR. Methods Proband exome sequencing was performed in 3 families, while targeted molecular testing for EMC1 [c.245C>T:p.(Thr82Met)] variant was performed in the other 2 families based on strong clinical suspicion and tribal origin. Sanger sequencing confirmed variant segregation with disease in all families. Results We identified 8 individuals from 5 Kuwaiti families with the homozygous pathogenic EMC1 variant [c.245C>T:p.(Thr82Met)] previously reported in a Turkish family with CAVIPMR. The variant was absent from Kuwait Medical Genetic Center database, thus unlikely to represent a population founder allelic variant. The average age at symptom onset was 11 weeks, with all families reporting either visual abnormalities, hypotonia, and/or global developmental delay (GDD) as the presenting features. Shared clinical features included GDD (8/8), microcephaly (8/8), truncal hypotonia (8/8), visual impairment (7/7), and failure to thrive (7/7). Other common features included hyperreflexia (5/6; 83%), peripheral hypertonia (3/5; 60%), dysmorphism (3/6; 50%), epilepsy (4/8; 50%), and chorea (3/8; 36%). Brain imaging showed cerebellar atrophy in 4/7 (57%) and cerebral atrophy in 3/6 (50%) individuals. Discussion The presence of exact biallelic homozygous EMC1 variant in 5 Kuwaiti families from the same tribe suggests a tribal founder allelic variant. The clinical features in this study are consistent with the phenotypic spectrum of EMC1-associated CAVIPMR in previous reports. The presence of chorea, first noted in this study, further expands the phenotypic spectrum. Our findings emphasize the importance of targeted EMC1 variant [c.245C>T:p.(Thr82Met)] testing for infants from affected tribe who present with visual impairment, GDD, and hypotonia.
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Affiliation(s)
- Nada T Alzayed
- From the College of Medicine (N.T.A., A.H. Alzuabi, R.A.A.), Health Science Center, Kuwait University; Section of Child Neurology (E.A.E.-A., D.M.), Department of Pediatrics, Adan Hospital, Ministry of Health, Hadiya; Kuwait Medical Genetics Centre (A. Alholle, A.H. Aboelanine, S.O., A.A.E., F.J.A., A. Alahmad, H.A., D.M.), Ministry of Health, Sulaibikhat; Department of Pediatrics (R.A., B.A.), Adan Hospital, Ministry of Health, Hadiya; Department of Pediatrics (H.A., D.M.), College of Medicine, Kuwait University, Safat; and Department of Pediatrics (H.A.), Farwaniya Hospital, Ministry of Health, Sabah Al-Nasser, Kuwait
| | - Abdullah H Alzuabi
- From the College of Medicine (N.T.A., A.H. Alzuabi, R.A.A.), Health Science Center, Kuwait University; Section of Child Neurology (E.A.E.-A., D.M.), Department of Pediatrics, Adan Hospital, Ministry of Health, Hadiya; Kuwait Medical Genetics Centre (A. Alholle, A.H. Aboelanine, S.O., A.A.E., F.J.A., A. Alahmad, H.A., D.M.), Ministry of Health, Sulaibikhat; Department of Pediatrics (R.A., B.A.), Adan Hospital, Ministry of Health, Hadiya; Department of Pediatrics (H.A., D.M.), College of Medicine, Kuwait University, Safat; and Department of Pediatrics (H.A.), Farwaniya Hospital, Ministry of Health, Sabah Al-Nasser, Kuwait
| | - Reem A Alqusaimi
- From the College of Medicine (N.T.A., A.H. Alzuabi, R.A.A.), Health Science Center, Kuwait University; Section of Child Neurology (E.A.E.-A., D.M.), Department of Pediatrics, Adan Hospital, Ministry of Health, Hadiya; Kuwait Medical Genetics Centre (A. Alholle, A.H. Aboelanine, S.O., A.A.E., F.J.A., A. Alahmad, H.A., D.M.), Ministry of Health, Sulaibikhat; Department of Pediatrics (R.A., B.A.), Adan Hospital, Ministry of Health, Hadiya; Department of Pediatrics (H.A., D.M.), College of Medicine, Kuwait University, Safat; and Department of Pediatrics (H.A.), Farwaniya Hospital, Ministry of Health, Sabah Al-Nasser, Kuwait
| | - Ehab A El-Anany
- From the College of Medicine (N.T.A., A.H. Alzuabi, R.A.A.), Health Science Center, Kuwait University; Section of Child Neurology (E.A.E.-A., D.M.), Department of Pediatrics, Adan Hospital, Ministry of Health, Hadiya; Kuwait Medical Genetics Centre (A. Alholle, A.H. Aboelanine, S.O., A.A.E., F.J.A., A. Alahmad, H.A., D.M.), Ministry of Health, Sulaibikhat; Department of Pediatrics (R.A., B.A.), Adan Hospital, Ministry of Health, Hadiya; Department of Pediatrics (H.A., D.M.), College of Medicine, Kuwait University, Safat; and Department of Pediatrics (H.A.), Farwaniya Hospital, Ministry of Health, Sabah Al-Nasser, Kuwait
| | - Abdullah Alholle
- From the College of Medicine (N.T.A., A.H. Alzuabi, R.A.A.), Health Science Center, Kuwait University; Section of Child Neurology (E.A.E.-A., D.M.), Department of Pediatrics, Adan Hospital, Ministry of Health, Hadiya; Kuwait Medical Genetics Centre (A. Alholle, A.H. Aboelanine, S.O., A.A.E., F.J.A., A. Alahmad, H.A., D.M.), Ministry of Health, Sulaibikhat; Department of Pediatrics (R.A., B.A.), Adan Hospital, Ministry of Health, Hadiya; Department of Pediatrics (H.A., D.M.), College of Medicine, Kuwait University, Safat; and Department of Pediatrics (H.A.), Farwaniya Hospital, Ministry of Health, Sabah Al-Nasser, Kuwait
| | - Ashraf H Aboelanine
- From the College of Medicine (N.T.A., A.H. Alzuabi, R.A.A.), Health Science Center, Kuwait University; Section of Child Neurology (E.A.E.-A., D.M.), Department of Pediatrics, Adan Hospital, Ministry of Health, Hadiya; Kuwait Medical Genetics Centre (A. Alholle, A.H. Aboelanine, S.O., A.A.E., F.J.A., A. Alahmad, H.A., D.M.), Ministry of Health, Sulaibikhat; Department of Pediatrics (R.A., B.A.), Adan Hospital, Ministry of Health, Hadiya; Department of Pediatrics (H.A., D.M.), College of Medicine, Kuwait University, Safat; and Department of Pediatrics (H.A.), Farwaniya Hospital, Ministry of Health, Sabah Al-Nasser, Kuwait
| | - Sherief Omar
- From the College of Medicine (N.T.A., A.H. Alzuabi, R.A.A.), Health Science Center, Kuwait University; Section of Child Neurology (E.A.E.-A., D.M.), Department of Pediatrics, Adan Hospital, Ministry of Health, Hadiya; Kuwait Medical Genetics Centre (A. Alholle, A.H. Aboelanine, S.O., A.A.E., F.J.A., A. Alahmad, H.A., D.M.), Ministry of Health, Sulaibikhat; Department of Pediatrics (R.A., B.A.), Adan Hospital, Ministry of Health, Hadiya; Department of Pediatrics (H.A., D.M.), College of Medicine, Kuwait University, Safat; and Department of Pediatrics (H.A.), Farwaniya Hospital, Ministry of Health, Sabah Al-Nasser, Kuwait
| | - Rasha Alsafi
- From the College of Medicine (N.T.A., A.H. Alzuabi, R.A.A.), Health Science Center, Kuwait University; Section of Child Neurology (E.A.E.-A., D.M.), Department of Pediatrics, Adan Hospital, Ministry of Health, Hadiya; Kuwait Medical Genetics Centre (A. Alholle, A.H. Aboelanine, S.O., A.A.E., F.J.A., A. Alahmad, H.A., D.M.), Ministry of Health, Sulaibikhat; Department of Pediatrics (R.A., B.A.), Adan Hospital, Ministry of Health, Hadiya; Department of Pediatrics (H.A., D.M.), College of Medicine, Kuwait University, Safat; and Department of Pediatrics (H.A.), Farwaniya Hospital, Ministry of Health, Sabah Al-Nasser, Kuwait
| | - Alaa A Elmonairy
- From the College of Medicine (N.T.A., A.H. Alzuabi, R.A.A.), Health Science Center, Kuwait University; Section of Child Neurology (E.A.E.-A., D.M.), Department of Pediatrics, Adan Hospital, Ministry of Health, Hadiya; Kuwait Medical Genetics Centre (A. Alholle, A.H. Aboelanine, S.O., A.A.E., F.J.A., A. Alahmad, H.A., D.M.), Ministry of Health, Sulaibikhat; Department of Pediatrics (R.A., B.A.), Adan Hospital, Ministry of Health, Hadiya; Department of Pediatrics (H.A., D.M.), College of Medicine, Kuwait University, Safat; and Department of Pediatrics (H.A.), Farwaniya Hospital, Ministry of Health, Sabah Al-Nasser, Kuwait
| | - Fatemah J Alali
- From the College of Medicine (N.T.A., A.H. Alzuabi, R.A.A.), Health Science Center, Kuwait University; Section of Child Neurology (E.A.E.-A., D.M.), Department of Pediatrics, Adan Hospital, Ministry of Health, Hadiya; Kuwait Medical Genetics Centre (A. Alholle, A.H. Aboelanine, S.O., A.A.E., F.J.A., A. Alahmad, H.A., D.M.), Ministry of Health, Sulaibikhat; Department of Pediatrics (R.A., B.A.), Adan Hospital, Ministry of Health, Hadiya; Department of Pediatrics (H.A., D.M.), College of Medicine, Kuwait University, Safat; and Department of Pediatrics (H.A.), Farwaniya Hospital, Ministry of Health, Sabah Al-Nasser, Kuwait
| | - Ahmad Alahmad
- From the College of Medicine (N.T.A., A.H. Alzuabi, R.A.A.), Health Science Center, Kuwait University; Section of Child Neurology (E.A.E.-A., D.M.), Department of Pediatrics, Adan Hospital, Ministry of Health, Hadiya; Kuwait Medical Genetics Centre (A. Alholle, A.H. Aboelanine, S.O., A.A.E., F.J.A., A. Alahmad, H.A., D.M.), Ministry of Health, Sulaibikhat; Department of Pediatrics (R.A., B.A.), Adan Hospital, Ministry of Health, Hadiya; Department of Pediatrics (H.A., D.M.), College of Medicine, Kuwait University, Safat; and Department of Pediatrics (H.A.), Farwaniya Hospital, Ministry of Health, Sabah Al-Nasser, Kuwait
| | - Hind Alsharhan
- From the College of Medicine (N.T.A., A.H. Alzuabi, R.A.A.), Health Science Center, Kuwait University; Section of Child Neurology (E.A.E.-A., D.M.), Department of Pediatrics, Adan Hospital, Ministry of Health, Hadiya; Kuwait Medical Genetics Centre (A. Alholle, A.H. Aboelanine, S.O., A.A.E., F.J.A., A. Alahmad, H.A., D.M.), Ministry of Health, Sulaibikhat; Department of Pediatrics (R.A., B.A.), Adan Hospital, Ministry of Health, Hadiya; Department of Pediatrics (H.A., D.M.), College of Medicine, Kuwait University, Safat; and Department of Pediatrics (H.A.), Farwaniya Hospital, Ministry of Health, Sabah Al-Nasser, Kuwait
| | - Buthaina Albash
- From the College of Medicine (N.T.A., A.H. Alzuabi, R.A.A.), Health Science Center, Kuwait University; Section of Child Neurology (E.A.E.-A., D.M.), Department of Pediatrics, Adan Hospital, Ministry of Health, Hadiya; Kuwait Medical Genetics Centre (A. Alholle, A.H. Aboelanine, S.O., A.A.E., F.J.A., A. Alahmad, H.A., D.M.), Ministry of Health, Sulaibikhat; Department of Pediatrics (R.A., B.A.), Adan Hospital, Ministry of Health, Hadiya; Department of Pediatrics (H.A., D.M.), College of Medicine, Kuwait University, Safat; and Department of Pediatrics (H.A.), Farwaniya Hospital, Ministry of Health, Sabah Al-Nasser, Kuwait
| | - Dana Marafi
- From the College of Medicine (N.T.A., A.H. Alzuabi, R.A.A.), Health Science Center, Kuwait University; Section of Child Neurology (E.A.E.-A., D.M.), Department of Pediatrics, Adan Hospital, Ministry of Health, Hadiya; Kuwait Medical Genetics Centre (A. Alholle, A.H. Aboelanine, S.O., A.A.E., F.J.A., A. Alahmad, H.A., D.M.), Ministry of Health, Sulaibikhat; Department of Pediatrics (R.A., B.A.), Adan Hospital, Ministry of Health, Hadiya; Department of Pediatrics (H.A., D.M.), College of Medicine, Kuwait University, Safat; and Department of Pediatrics (H.A.), Farwaniya Hospital, Ministry of Health, Sabah Al-Nasser, Kuwait
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Shinsato RN, Correa CG, Herai RH. Genetic network analysis indicate that individuals affected by neurodevelopmental conditions have genetic variations associated with ophthalmologic alterations: A critical review of literature. Gene 2024; 908:148246. [PMID: 38325665 DOI: 10.1016/j.gene.2024.148246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 01/19/2024] [Accepted: 02/02/2024] [Indexed: 02/09/2024]
Abstract
Changes in the nervous system are related to a wide range of mental disorders, which include neurodevelopmental disorders (NDD) that are characterized by early onset mental conditions, such as schizophrenia and autism spectrum disorders and correlated conditions (ASD). Previous studies have shown distinct genetic components associated with diverse schizophrenia and ASD phenotypes, with mostly focused on rescuing neural phenotypes and brain activity, but alterations related to vision are overlooked. Thus, as the vision is composed by the eyes that itself represents a part of the brain, with the retina being formed by neurons and cells originating from the glia, genetic variations affecting the brain can also affect the vision. Here, we performed a critical systematic literature review to screen for all genetic variations in individuals presenting NDD with reported alterations in vision. Using these restricting criteria, we found 20 genes with distinct types of genetic variations, inherited or de novo, that includes SNP, SNV, deletion, insertion, duplication or indel. The variations occurring within protein coding regions have different impact on protein formation, such as missense, nonsense or frameshift. Moreover, a molecular analysis of the 20 genes found revealed that 17 shared a common protein-protein or genetic interaction network. Moreover, gene expression analysis in samples from the brain and other tissues indicates that 18 of the genes found are highly expressed in the brain and retina, indicating their potential role in adult vision phenotype. Finally, we only found 3 genes from our study described in standard public databanks of ophthalmogenetics, suggesting that the other 17 genes could be novel target for vision diseases.
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Affiliation(s)
- Rogério N Shinsato
- Unisalesiano, Araçatuba, São Paulo, Brazil; Laboratory of Bioinformatics and Neurogenetics (LaBiN/LEM), Graduate Program in Health Sciences, School of Medicine and Life Sciences, Pontifícia Universidade Católica do Paraná (PUCPR), Curitiba, Paraná, 80215-901, Brazil.
| | - Camila Graczyk Correa
- Laboratory of Bioinformatics and Neurogenetics (LaBiN/LEM), Graduate Program in Health Sciences, School of Medicine and Life Sciences, Pontifícia Universidade Católica do Paraná (PUCPR), Curitiba, Paraná, 80215-901, Brazil
| | - Roberto H Herai
- Laboratory of Bioinformatics and Neurogenetics (LaBiN/LEM), Graduate Program in Health Sciences, School of Medicine and Life Sciences, Pontifícia Universidade Católica do Paraná (PUCPR), Curitiba, Paraná, 80215-901, Brazil; Research Division, Buko Kaesemodel Institute (IBK), Curitiba, Paraná 80240-000, Brazil; Research Division, 9p Brazil Association (A9pB), Santa Maria, Rio Grande do Sul 97060-580, Brazil.
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Sun K, Liu L, Jiang X, Wang H, Wang L, Yang Y, Liu W, Zhang L, Zhao X, Zhu X. The endoplasmic reticulum membrane protein complex subunit Emc6 is essential for rhodopsin localization and photoreceptor cell survival. Genes Dis 2024; 11:1035-1049. [PMID: 37692493 PMCID: PMC10492031 DOI: 10.1016/j.gendis.2023.03.033] [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: 09/21/2022] [Revised: 02/17/2023] [Accepted: 03/29/2023] [Indexed: 09/12/2023] Open
Abstract
The endoplasmic reticulum (ER) membrane protein complex (EMC) is responsible for monitoring the biogenesis and synthetic quality of membrane proteins with tail-anchored or multiple transmembrane domains. The EMC subunit EMC6 is one of the core members of EMC and forms an enclosed hydrophilic vestibule in cooperation with EMC3. Despite studies demonstrating that deletion of EMC3 led to rhodopsin mislocalization in rod photoreceptors of mice, the precise mechanism leading to the failure of rhodopsin trafficking remains unclear. Here, we generated the first rod photoreceptor-specific knockout of Emc6 (RKO) and cone photoreceptor-specific knockout of Emc6 (CKO) mouse models. Deficiency of Emc6 in rod photoreceptors led to progressive shortening of outer segments (OS), impaired visual function, mislocalization and reduced expression of rhodopsin, and increased gliosis in rod photoreceptors. In addition, CKO mice displayed the progressive death of cone photoreceptors and abnormal localization of cone opsin protein. Subsequently, proteomics analysis of the RKO mouse retina illustrated that several cilium-related proteins, particularly anoctamin-2 (ANO2) and transmembrane protein 67 (TMEM67), were significantly down-regulated prior to OS degeneration. Detrimental rod photoreceptor cilia and mislocalized membrane disc proteins were evident in RKO mice. Our data revealed that in addition to monitoring the synthesis of rhodopsin-dominated membrane disc proteins, EMC6 also impacted rod photoreceptors' ciliogenesis by regulating the synthesis of membrane proteins associated with cilia, contributing to the mislocalization of membrane disc proteins.
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Affiliation(s)
- Kuanxiang Sun
- Health Management Center, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
- Key Laboratory of Tibetan Medicine Research, Chinese Academy of Sciences and Qinghai Provincial Key Laboratory of Tibetan Medicine Research, Northwest Institute of Plateau Biology, Xining, Qinghai 810008, China
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
- Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, China
| | - Lu Liu
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
| | - Xiaoyan Jiang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
| | - Heting Wang
- Health Management Center, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
| | - Lin Wang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
| | - Yeming Yang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
| | - Wenjing Liu
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
| | - Lin Zhang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
| | - Xiaohui Zhao
- Key Laboratory of Tibetan Medicine Research, Chinese Academy of Sciences and Qinghai Provincial Key Laboratory of Tibetan Medicine Research, Northwest Institute of Plateau Biology, Xining, Qinghai 810008, China
| | - Xianjun Zhu
- Health Management Center, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
- Key Laboratory of Tibetan Medicine Research, Chinese Academy of Sciences and Qinghai Provincial Key Laboratory of Tibetan Medicine Research, Northwest Institute of Plateau Biology, Xining, Qinghai 810008, China
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
- Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, China
- Department of Ophthalmology, The First People's Hospital of Shangqiu, Shangqiu, Henan 476000, China
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Li S, Yang M, Zhao R, Peng L, Liu W, Jiang X, He Y, Dai E, Zhang L, Yang Y, Shi Y, Zhao P, Yang Z, Zhu X. Defective EMC1 drives abnormal retinal angiogenesis via Wnt/β-catenin signaling and may be associated with the pathogenesis of familial exudative vitreoretinopathy. Genes Dis 2023; 10:2572-2585. [PMID: 37554197 PMCID: PMC10404869 DOI: 10.1016/j.gendis.2022.10.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 09/10/2022] [Accepted: 10/01/2022] [Indexed: 11/06/2022] Open
Abstract
Endoplasmic reticulum (ER) membrane protein complex (EMC) is required for the co-translational insertion of newly synthesized multi-transmembrane proteins. Compromised EMC function in different cell types has been implicated in multiple diseases. Using inducible genetic mouse models, we revealed defects in retinal vascularization upon endothelial cell (EC) specific deletion of Emc1, the largest subunit of EMC. Loss of Emc1 in ECs led to reduced vascular progression and vascular density, diminished tip cell sprouts, and vascular leakage. We then performed an unbiased transcriptomic analysis on human retinal microvascular endothelial cells (HRECs) and revealed a pivotal role of EMC1 in the β-catenin signaling pathway. Further in-vitro and in-vivo experiments proved that loss of EMC1 led to compromised β-catenin signaling activity through reduced expression of Wnt receptor FZD4, which could be restored by lithium chloride (LiCl) treatment. Driven by these findings, we screened genomic DNA samples from familial exudative vitreoretinopathy (FEVR) patients and identified one heterozygous variant in EMC1 that co-segregated with FEVR phenotype in the family. In-vitro expression experiments revealed that this variant allele failed to facilitate the expression of FZD4 on the plasma membrane and activate the β-catenin signaling pathway, which might be a main cause of FEVR. In conclusion, our findings reveal that variants in EMC1 gene cause compromised β-catenin signaling activity, which may be associated with the pathogenesis of FEVR.
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Affiliation(s)
- Shujin Li
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Center for Medical Genetics, Department of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
- Research Unit for Blindness Prevention of the Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, China
| | - Mu Yang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Center for Medical Genetics, Department of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
- Research Unit for Blindness Prevention of the Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, China
| | - Rulian Zhao
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Center for Medical Genetics, Department of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
- Research Unit for Blindness Prevention of the Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, China
| | - Li Peng
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Center for Medical Genetics, Department of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
| | - Wenjing Liu
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Center for Medical Genetics, Department of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
| | - Xiaoyan Jiang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Center for Medical Genetics, Department of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
| | - Yunqi He
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Center for Medical Genetics, Department of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
| | - Erkuan Dai
- Department of Ophthalmology, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Lin Zhang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Center for Medical Genetics, Department of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
| | - Yeming Yang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Center for Medical Genetics, Department of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
| | - Yi Shi
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Center for Medical Genetics, Department of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
| | - Peiquan Zhao
- Department of Ophthalmology, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Zhenglin Yang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Center for Medical Genetics, Department of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
- Research Unit for Blindness Prevention of the Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, China
| | - Xianjun Zhu
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, Center for Medical Genetics, Department of Laboratory Medicine, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, China
- Research Unit for Blindness Prevention of the Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, Sichuan 610072, China
- Key Laboratory of Tibetan Medicine Research, Chinese Academy of Sciences and Qinghai Provincial Key Laboratory of Tibetan Medicine Research, Northwest Institute of Plateau Biology, Xining, Qinghai 810008, China
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6
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Li X, Jiang Z, Su Y, Wang K, Jiang X, Sun K, Yang Y, Zhou Y, Zhu X, Zhang L. Deletion of Emc1 in photoreceptor cells causes retinal degeneration in mice. FEBS J 2023; 290:4356-4370. [PMID: 37098815 DOI: 10.1111/febs.16807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/30/2023] [Accepted: 04/25/2023] [Indexed: 04/27/2023]
Abstract
The endoplasmic reticulum membrane protein complex (EMC) plays a critical role in the synthesis of multipass membrane proteins. Genetic studies indicated that mutations in EMC1 gene were associated with retinal degeneration diseases; however, the role of EMC1 in photoreceptor has not been confirmed. Here, we show that Emc1 ablation in the photoreceptor cells of mice recapitulated the retinitis pigmentosa phenotypes, including an attenuated scotopic electroretinogram response and the progressive degeneration of rod cells and cone cells. Histopathological examination of tissues from rod-specific Emc1 knockout mice revealed mislocalized rhodopsin and irregularly arranged cone cells at the age of 2 months. Further immunoblotting analysis revealed decreased levels of membrane proteins and endoplasmic reticulum chaperones in 1-month-old rod-specific Emc1 knockout mice retinae, and this led us to speculate that the loss of membrane proteins is the main cause of the degeneration of photoreceptors. EMC1 most likely regulated the membrane protein levels at an earlier step in the biosynthetic process before the proteins translocated into the endoplasmic reticulum. The present study demonstrates the essential roles of Emc1 in photoreceptor cells, and reveals the mechanism through which EMC1 mutations are linked to retinitis pigmentosa.
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Affiliation(s)
- Xiao Li
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Zhilin Jiang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Yujing Su
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Kaifang Wang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Xiaoyan Jiang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Kuanxiang Sun
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Yeming Yang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Yu Zhou
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Xianjun Zhu
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
- Key Laboratory of Tibetan Medicine Research, Chinese Academy of Sciences and Qinghai Provincial Key Laboratory of Tibetan Medicine Research, Northwest Institute of Plateau Biology, Xining, China
- Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
| | - Lin Zhang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study and Department of Laboratory Medicine, Center for Medical Genetics, Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
- Key Laboratory of Tibetan Medicine Research, Chinese Academy of Sciences and Qinghai Provincial Key Laboratory of Tibetan Medicine Research, Northwest Institute of Plateau Biology, Xining, China
- Research Unit for Blindness Prevention of Chinese Academy of Medical Sciences (2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
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7
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Bryen SJ, Zhang K, Dziaduch G, Bommireddipalli S, Naseri T, Reupena MS, Viali S, Minster RL, Waddell LB, Charlton A, O’Grady GL, Evesson FJ, Cooper ST. Compound heterozygous splicing variants expand the genotypic spectrum of EMC1-related disorders. Clin Genet 2023; 103:553-559. [PMID: 36799557 PMCID: PMC10101692 DOI: 10.1111/cge.14311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 02/09/2023] [Accepted: 02/13/2023] [Indexed: 02/18/2023]
Abstract
EMC1 encodes subunit 1 of the endoplasmic reticulum (ER) membrane protein complex (EMC), a transmembrane domain insertase involved in membrane protein biosynthesis. Variants in EMC1 are described as a cause of global developmental delay, hypotonia, cortical visual impairment, and commonly, cerebral atrophy on MRI scan. We report an individual with severe global developmental delay and progressive cerebellar atrophy in whom exome sequencing identified a heterozygous essential splice-site variant in intron-3 of EMC1 (NM_015047.3:c.287-1G>A). Whole genome sequencing (WGS) identified a deep intronic variant in intron-20 of EMC1 (NM_015047.3:c.2588-771C>G) that was poorly predicted by in silico programs to disrupt pre-mRNA splicing. Reverse Transcription-PCR (RT-PCR) revealed stochastic activation of a pseudo-exon associated with the c.2588-771C>G variant and mis-splicing arising from the c.287-1G>A variant. This case highlights the utility of WGS and RNA studies to identify and assess likely pathogenicity of deep intronic variants and expands the genotypic and phenotypic spectrum of EMC1-related disorders.
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Affiliation(s)
- Samantha J. Bryen
- Kids Neuroscience Centre, The Children’s Hospital at Westmead, NSW, Australia
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, NSW, Australia
| | - Katharine Zhang
- Kids Neuroscience Centre, The Children’s Hospital at Westmead, NSW, Australia
- Functional Neuromics, Children’s Medical Research Institute, Westmead, NSW, Australia
| | - Gregory Dziaduch
- Kids Neuroscience Centre, The Children’s Hospital at Westmead, NSW, Australia
- Functional Neuromics, Children’s Medical Research Institute, Westmead, NSW, Australia
| | - Shobhana Bommireddipalli
- Kids Neuroscience Centre, The Children’s Hospital at Westmead, NSW, Australia
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, NSW, Australia
| | - Take Naseri
- Ministry of Health, Apia, Samoa
- International Health Institute, School of Public Health, Brown University, Providence, RI, USA
| | | | | | | | - Leigh B. Waddell
- Kids Neuroscience Centre, The Children’s Hospital at Westmead, NSW, Australia
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, NSW, Australia
| | | | - Gina L. O’Grady
- Kids Neuroscience Centre, The Children’s Hospital at Westmead, NSW, Australia
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, NSW, Australia
- Paediatric Neuroservices, Starship Child Health, Auckland, New Zealand
| | - Frances J. Evesson
- Kids Neuroscience Centre, The Children’s Hospital at Westmead, NSW, Australia
- Functional Neuromics, Children’s Medical Research Institute, Westmead, NSW, Australia
| | - Sandra T. Cooper
- Kids Neuroscience Centre, The Children’s Hospital at Westmead, NSW, Australia
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, NSW, Australia
- Functional Neuromics, Children’s Medical Research Institute, Westmead, NSW, Australia
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8
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Wang G, Wang Y, Gao C, Xie W. Novel compound heterozygous variants in EMC1 associated with global developmental delay: a lesson from a non-silent synonymous exonic mutation. Front Mol Neurosci 2023; 16:1153156. [PMID: 37187958 PMCID: PMC10175691 DOI: 10.3389/fnmol.2023.1153156] [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: 01/29/2023] [Accepted: 04/10/2023] [Indexed: 05/17/2023] Open
Abstract
Background The endoplasmic reticulum-membrane protein complex (EMC) as a molecular chaperone is required for the proper synthesis, folding and traffic of several transmembrane proteins. Variants in the subunit 1 of EMC (EMC1) have been implicated in neurodevelopmental disorders. Methods Whole exome sequencing (WES) with Sanger sequencing validation was performed for a Chinese family, including the proband (a 4-year-old girl who displayed global developmental delay, severe hypotonia and visual impairment), her affected younger sister and her non-consanguineous parents. RT-PCR assay and Sanger sequencing were used to detect abnormal RNA splicing. Results Novel compound heterozygous variants in EMC1, including the maternally inherited chr1: 19566812_1956800delinsATTCTACTT[hg19];NM_015047.3:c.765_777delins ATTCTACTT;p.(Leu256fsTer10) and the paternally inherited chr1:19549890G> A[hg19];NM_015047.3:c.2376G>A;p.(Val792=) are identified in the proband and her affected sister. RT-PCR assay followed by Sanger sequencing reveals that the c.2376G>A variant leads to aberrant splicing, with retention of intron 19 (561bp) in the mature mRNA, which is presumed to introduce a premature translational termination codon (p.(Val792fsTer31)). Conclusion Novel compound heterozygous variants in EMC1 have been identified in individuals with global developmental delay. Non-silent synonymous mutations should be kept in mind in genetic analysis.
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Affiliation(s)
- Ge Wang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Yanli Wang
- Department of Rehabilitation Medicine, Children's Hospital Affiliated to Zhengzhou University, Henan Children's Hospital, Zhengzhou, China
| | - Chao Gao
- Department of Rehabilitation Medicine, Children's Hospital Affiliated to Zhengzhou University, Henan Children's Hospital, Zhengzhou, China
- *Correspondence: Chao Gao
| | - Wanqin Xie
- National Health Committee Key Laboratory of Birth Defects for Research and Prevention, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, China
- Wanqin Xie
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9
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Bhardwaj A, Yadav A, Yadav M, Tanwar M. Genetic dissection of non-syndromic retinitis pigmentosa. Indian J Ophthalmol 2022; 70:2355-2385. [PMID: 35791117 PMCID: PMC9426071 DOI: 10.4103/ijo.ijo_46_22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Retinitis pigmentosa (RP) belongs to a group of pigmentary retinopathies. It is the most common form of inherited retinal dystrophy, characterized by progressive degradation of photoreceptors that leads to nyctalopia, and ultimately, complete vision loss. RP is distinguished by the continuous retinal degeneration that progresses from the mid-periphery to the central and peripheral retina. RP was first described and named by Franciscus Cornelius Donders in the year 1857. It is one of the leading causes of bilateral blindness in adults, with an incidence of 1 in 3000 people worldwide. In this review, we are going to focus on the genetic heterogeneity of this disease, which is provided by various inheritance patterns, numerosity of variations and inter-/intra-familial variations based upon penetrance and expressivity. Although over 90 genes have been identified in RP patients, the genetic cause of approximately 50% of RP cases remains unknown. Heterogeneity of RP makes it an extremely complicated ocular impairment. It is so complicated that it is known as “fever of unknown origin”. For prognosis and proper management of the disease, it is necessary to understand its genetic heterogeneity so that each phenotype related to the various genetic variations could be treated.
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Affiliation(s)
- Aarti Bhardwaj
- Department of Genetics, M. D. University, Rohtak, Haryana, India
| | - Anshu Yadav
- Department of Genetics, M. D. University, Rohtak, Haryana, India
| | - Manoj Yadav
- Department of Genetics, M. D. University, Rohtak, Haryana, India
| | - Mukesh Tanwar
- Department of Genetics, M. D. University, Rohtak, Haryana, India
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Kaiyrzhanov R, Rocca C, Suri M, Gulieva S, Zaki MS, Henig NZ, Siquier K, Guliyeva U, Mounir SM, Marom D, Allahverdiyeva A, Megahed H, van Bokhoven H, Cantagrel V, Rad A, Pourkeramti A, Dehghani B, Shao DD, Markus-Bustani K, Sofrin-Drucker E, Orenstein N, Salayev K, Arrigoni F, Houlden H, Maroofian R. Biallelic loss of EMC10 leads to mild to severe intellectual disability. Ann Clin Transl Neurol 2022; 9:1080-1089. [PMID: 35684946 PMCID: PMC9268894 DOI: 10.1002/acn3.51602] [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: 03/14/2022] [Revised: 05/25/2022] [Accepted: 05/25/2022] [Indexed: 11/22/2022] Open
Abstract
The endoplasmic reticulum membrane protein complex subunit 10 (EMC10) is a highly conserved protein responsible for the post‐translational insertion of tail‐anchored membrane proteins into the endoplasmic reticulum in a defined topology. Two biallelic variants in EMC10 have previously been associated with a neurodevelopmental disorder. Utilizing exome sequencing and international data sharing we have identified 10 affected individuals from six independent families with five new biallelic loss‐of‐function and one previously reported recurrent EMC10 variants. This report expands the molecular and clinical spectrum of EMC10 deficiency, provides a comprehensive dysmorphological assessment and highlights an overlap between the clinical features of EMC10‐and EMC1‐related disease.
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Affiliation(s)
- Rauan Kaiyrzhanov
- Department of Neuromuscular Disorders, Queen Square Institute of Neurology, University College London, London, UK
| | - Clarissa Rocca
- Department of Neuromuscular Disorders, Queen Square Institute of Neurology, University College London, London, UK
| | - Mohnish Suri
- Clinical Genetics Service, Nottingham University Hospitals NHS Trust, Nottingham, UK
| | - Sughra Gulieva
- MediClub Hospital, 45, Uzeyir Hajibeyli str., Baku, AZ1010, Azerbaijan
| | - Maha S Zaki
- Human Genetics and Genome Research Division, Clinical Genetics Department, National Research Centre, Cairo, Egypt
| | - Noa Z Henig
- Genetics Institute, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Karine Siquier
- Developmental Brain Disorders Laboratory, Imagine Institute, INSERM UMR, Université Paris Cité, Paris, France
| | - Ulviyya Guliyeva
- MediClub Hospital, 45, Uzeyir Hajibeyli str., Baku, AZ1010, Azerbaijan
| | - Samir M Mounir
- Pediatrics Department, Faculty of Medicine, El-Minia University, Minia, Egypt
| | - Daphna Marom
- Genetics Institute, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | | | - Hisham Megahed
- Clinical Genetics Department, National Research Centre, Cairo, Egypt
| | - Hans van Bokhoven
- Deparment of Human Genetics, Donders Center for Brain Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Vincent Cantagrel
- Developmental Brain Disorders Laboratory, Imagine Institute, INSERM UMR, Université Paris Cité, Paris, France
| | - Aboulfazl Rad
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, Eberhard Karls University, Tübingen, 72076, Germany
| | - Alemeh Pourkeramti
- Medical Biotechnology Research Center, Ashkezar University, Ashkezar, Yazd, Iran
| | - Boshra Dehghani
- Medical Biotechnology Research Center, Ashkezar University, Ashkezar, Yazd, Iran
| | - Diane D Shao
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, USA.,Division of Genetics and Genomics, Department of Pediatrics, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Keren Markus-Bustani
- Raphael Recanati Genetic Institute, Rabin Medical Center-Beilinson Hospital, Petach Tikva, Israel
| | - Efrat Sofrin-Drucker
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Department of Pediatric Genetics, Schneider Children Medical Center of Israel, Petah Tikva, Israel
| | - Naama Orenstein
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Department of Pediatric Genetics, Schneider Children Medical Center of Israel, Petah Tikva, Israel
| | - Kamran Salayev
- Department of Neurology, Azerbaijan Medical University, Baku, Azerbaijan
| | - Filippo Arrigoni
- Paediatric Radiology and Neuroradiology Department, V. Buzzi Children's Hospital, Milan, Italy
| | - Henry Houlden
- Department of Neuromuscular Disorders, Queen Square Institute of Neurology, University College London, London, UK
| | - Reza Maroofian
- Department of Neuromuscular Disorders, Queen Square Institute of Neurology, University College London, London, UK
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11
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Chung HL, Rump P, Lu D, Glassford MR, Mok JW, Fatih J, Basal A, Marcogliese PC, Kanca O, Rapp M, Fock JM, Kamsteeg EJ, Lupski JR, Larson A, Haninbal MC, Bellen H, Harel T. De novo variants in EMC1 lead to neurodevelopmental delay and cerebellar degeneration and affect glial function in Drosophila. Hum Mol Genet 2022; 31:3231-3244. [PMID: 35234901 PMCID: PMC9523557 DOI: 10.1093/hmg/ddac053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 02/22/2022] [Accepted: 02/23/2022] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The endoplasmic reticulum (ER)-membrane protein complex (EMC) is a multi-protein transmembrane complex composed of 10 subunits that functions as a membrane-protein chaperone. Variants in EMC1 lead to neurodevelopmental delay and cerebellar degeneration. Multiple families with biallelic variants have been published, yet to date, only a single report of a monoallelic variant has been described, and functional evidence is sparse. METHODS Exome sequencing was used to investigate the genetic cause underlying severe developmental delay in three unrelated children. EMC1 variants were modeled in Drosophila, using loss-of-function (LoF) and overexpression studies. Glial-specific and neuronal-specific assays were used to determine whether the dysfunction was specific to one cell type. RESULTS Exome sequencing identified de novo variants in EMC1 in three individuals affected by global developmental delay, hypotonia, seizures, visual impairment and cerebellar atrophy. All variants were located at Pro582 or Pro584. Drosophila studies indicated that imbalance of EMC1-either overexpression or knockdown-results in pupal lethality and suggest that the tested homologous variants are LoF alleles. In addition, glia-specific gene dosage, overexpression or knockdown, of EMC1 led to lethality, whereas neuron-specific alterations were tolerated. DISCUSSION We establish de novo monoallelic EMC1 variants as causative of a neurological disease trait by providing functional evidence in a Drosophila model. The identified variants failed to rescue the lethality of a null allele. Variations in dosage of the wild-type EMC1, specifically in glia, lead to pupal lethality, which we hypothesize results from the altered stoichiometry of the multi-subunit protein complex EMC.
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Affiliation(s)
- Hyung-Lok Chung
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA,Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - Patrick Rump
- University of Groningen, University Medical Centre Groningen, Department of Genetics, Groningen 9700 RB, The Netherlands
| | - Di Lu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Megan R Glassford
- Division of Pediatric Genetics, Metabolism & Genomic Medicine, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Jung-Wan Mok
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Jawid Fatih
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Adily Basal
- Department of Genetics, Hadassah Medical Organization, Jerusalem 9112001, Israel
| | - Paul C Marcogliese
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Oguz Kanca
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Michele Rapp
- University of Colorado Anschutz Medical Campus, Aurora, CO 60045, USA
| | - Johanna M Fock
- University of Groningen, University Medical Centre Groningen, Department of Neurology, Groningen 9700 RB, The Netherlands
| | - Erik-Jan Kamsteeg
- Department of Human Genetics, Radboud University Medical Centre, Nijmegen 6500 HB, The Netherlands
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA,Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030, USA,Department of Pediatrics, Texas Children's Hospital, Houston, TX 77030, USA
| | - Austin Larson
- University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO 60045, United States
| | - Mark C Haninbal
- Division of Pediatric Genetics, Metabolism & Genomic Medicine, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Hugo Bellen
- To whom correspondence should be addressed at: Department of Genetics, Hadassah-Hebrew University Medical Center, POB 12000, Jerusalem 9112001, Israel. Tel: +(972)-2-6776329; Fax: +(972)-2-6777618; ; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA. Tel: +1 832824-8750; Fax: +1832825-1240;
| | - Tamar Harel
- To whom correspondence should be addressed at: Department of Genetics, Hadassah-Hebrew University Medical Center, POB 12000, Jerusalem 9112001, Israel. Tel: +(972)-2-6776329; Fax: +(972)-2-6777618; ; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA. Tel: +1 832824-8750; Fax: +1832825-1240;
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12
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The ER membrane protein complex subunit Emc3 controls angiogenesis via the FZD4/WNT signaling axis. SCIENCE CHINA-LIFE SCIENCES 2021; 64:1868-1883. [PMID: 34128175 DOI: 10.1007/s11427-021-1941-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 04/29/2021] [Indexed: 02/08/2023]
Abstract
The endoplasmic reticulum (ER) membrane protein complex (EMC) regulates the synthesis and quality control of membrane proteins with multiple transmembrane domains. One of the membrane spanning subunits, EMC3, is a core member of the EMC complex that provides essential hydrophilic vestibule for substrate insertion. Here, we show that the EMC subunit Emc3 plays critical roles in the retinal vascular angiogenesis by regulating Norrin/Wnt signaling. Postnatal endothelial cell (EC)-specific deletion of Emc3 led to retarded retinal vascular development with a hyperpruned vascular network, the appearance of blunt-ended, aneurysm-like tip endothelial cells (ECs) with reduced numbers of filopodia and leakage of erythrocytes at the vascular front. Diminished tube formation and cell proliferation were also observed in EMC3 depleted human retinal endothelial cells (HRECs). We then discovered a critical role for EMC3 in expression of FZD4 receptor of β-catenin signaling using RNA sequencing, real-time quantitative PCR (RT-qPCR) and luciferase reporter assay. Moreover, augmentation of Wnt activity via lithium chloride (LiCl) treatment remarkably enhanced β-catenin signaling and cell proliferation of HRECs. Additionally, LiCl partially reversed the angiogenesis defects in Emc3-cKO mice. Our data reveal that Emc3 plays essential roles in angiogenesis through direct control of FZD4 expression and Norrin/β-catenin signaling.
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