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Shnaider TA, Khabarova AA, Morozova KN, Yunusova AM, Yakovleva SA, Chvileva AS, Wolf ER, Kiseleva EV, Grigor'eva EV, Voinova VY, Lagarkova MA, Pomerantseva EA, Musatova EV, Smirnov AV, Smirnova AV, Stoklitskaya DS, Arefieva TI, Larina DA, Nikitina TV, Pristyazhnyuk IE. Ultrastructural Abnormalities in Induced Pluripotent Stem Cell-Derived Neural Stem Cells and Neurons of Two Cohen Syndrome Patients. Cells 2023; 12:2702. [PMID: 38067130 PMCID: PMC10705360 DOI: 10.3390/cells12232702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 11/12/2023] [Accepted: 11/20/2023] [Indexed: 12/18/2023] Open
Abstract
Cohen syndrome is an autosomal recessive disorder caused by VPS13B (COH1) gene mutations. This syndrome is significantly underdiagnosed and is characterized by intellectual disability, microcephaly, autistic symptoms, hypotension, myopia, retinal dystrophy, neutropenia, and obesity. VPS13B regulates intracellular membrane transport and supports the Golgi apparatus structure, which is critical for neuron formation. We generated induced pluripotent stem cells from two patients with pronounced manifestations of Cohen syndrome and differentiated them into neural stem cells and neurons. Using transmission electron microscopy, we documented multiple new ultrastructural changes associated with Cohen syndrome in the neuronal cells. We discovered considerable disturbances in the structure of some organelles: Golgi apparatus fragmentation and swelling, endoplasmic reticulum structural reorganization, mitochondrial defects, and the accumulation of large autophagosomes with undigested contents. These abnormalities underline the ultrastructural similarity of Cohen syndrome to many neurodegenerative diseases. The cell models that we developed based on patient-specific induced pluripotent stem cells can serve to uncover not only neurodegenerative processes, but the causes of intellectual disability in general.
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Affiliation(s)
- Tatiana A Shnaider
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Anna A Khabarova
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Ksenia N Morozova
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia
| | - Anastasia M Yunusova
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Sophia A Yakovleva
- Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia
| | - Anastasia S Chvileva
- Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia
| | - Ekaterina R Wolf
- Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia
| | - Elena V Kiseleva
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Elena V Grigor'eva
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Viktori Y Voinova
- Clinical Research Institute of Pediatrics Named after Acad. Y.E. Veltischev, Moscow 125412, Russia
- The Mental Health Research Center, Moscow 115522, Russia
| | - Maria A Lagarkova
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow 119435, Russia
| | | | | | - Alexander V Smirnov
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Anna V Smirnova
- Clinical Research Institute of Pediatrics Named after Acad. Y.E. Veltischev, Moscow 125412, Russia
| | | | - Tatiana I Arefieva
- National Medical Research Centre of Cardiology Named after Academician E. I. Chazov., Moscow 121552, Russia
| | - Daria A Larina
- Clinical Research Institute of Pediatrics Named after Acad. Y.E. Veltischev, Moscow 125412, Russia
| | - Tatiana V Nikitina
- Research Institute of Medical Genetics, Tomsk National Research Medical Center, Tomsk 634050, Russia
| | - Inna E Pristyazhnyuk
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
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Montillot C, Skutunova E, Ayushma, Dubied M, Lahmar A, Nguyen S, Peerally B, Prin F, Duffourd Y, Thauvin-Robinet C, Duplomb L, Wang H, Ansar M, Faivre L, Navarro N, Minocha S, Collins SC, Yalcin B. Characterization of Vps13b-mutant mice reveals neuroanatomical and behavioral phenotypes with females less affected. Neurobiol Dis 2023; 185:106259. [PMID: 37573958 DOI: 10.1016/j.nbd.2023.106259] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 07/26/2023] [Accepted: 08/11/2023] [Indexed: 08/15/2023] Open
Abstract
The vacuolar protein sorting-associated protein 13B (VPS13B) is a large and highly conserved protein. Disruption of VPS13B causes the autosomal recessive Cohen syndrome, a rare disorder characterized by microcephaly and intellectual disability among other features, including developmental delay, hypotonia, and friendly-personality. However, the underlying mechanisms by which VPS13B disruption leads to brain dysfunction still remain unexplained. To gain insights into the neuropathogenesis of Cohen syndrome, we systematically characterized brain changes in Vps13b-mutant mice and compared murine findings to 235 previously published and 17 new patients diagnosed with VPS13B-related Cohen syndrome. We showed that Vps13b is differentially expressed across brain regions with the highest expression in the cerebellum, the hippocampus and the cortex with postnatal peak. Half of the Vps13b-/- mice die during the first week of life. The remaining mice have a normal lifespan and display the core phenotypes of the human disease, including microcephaly, growth delay, hypotonia, altered memory, and enhanced sociability. Systematic 2D and 3D brain histo-morphological analyses reveal specific structural changes in the brain starting after birth. The dentate gyrus is the brain region with the most prominent reduction in size, while the motor cortex is specifically thinner in layer VI. The fornix, the fasciculus retroflexus, and the cingulate cortex remain unaffected. Interestingly, these neuroanatomical changes implicate an increase of neuronal death during infantile stages with no progression in adulthood suggesting that VPS13B promotes neuronal survival early in life. Importantly, whilst both sexes were affected, some neuroanatomical and behavioral phenotypes were less pronounced or even absent in females. We evaluate sex differences in Cohen patients and conclude that females are less affected both in mice and patients. Our findings provide new insights about the neurobiology of VPS13B and highlight previously unreported brain phenotypes while defining Cohen syndrome as a likely new entity of non-progressive infantile neurodegeneration.
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Affiliation(s)
- Charlotte Montillot
- Université de Bourgogne, 21000 Dijon, France; Inserm Unit 1231, 21000 Dijon, France
| | - Emilia Skutunova
- Université de Bourgogne, 21000 Dijon, France; Inserm Unit 1231, 21000 Dijon, France
| | - Ayushma
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi (IITD), Hauz Khas, New Delhi 110016, India
| | - Morgane Dubied
- Biogéosciences, UMR 6282 CNRS, EPHE, Université de Bourgogne, 21000 Dijon, France
| | - Adam Lahmar
- Université de Bourgogne, 21000 Dijon, France; Inserm Unit 1231, 21000 Dijon, France
| | - Sylvie Nguyen
- Université de Bourgogne, 21000 Dijon, France; Inserm Unit 1231, 21000 Dijon, France
| | - Benazir Peerally
- Université de Bourgogne, 21000 Dijon, France; Inserm Unit 1231, 21000 Dijon, France
| | - Fabrice Prin
- Crick Advanced Light Microscopy Facility, The Francis Crick Institute, London NW1 1AT, UK
| | - Yannis Duffourd
- Université de Bourgogne, 21000 Dijon, France; Inserm Unit 1231, 21000 Dijon, France; Unité Fonctionnelle Innovation en Diagnostic génomique des maladies rares, FHU-TRANSLAD, Dijon University Hospital, 21000 Dijon, France
| | - Christel Thauvin-Robinet
- Université de Bourgogne, 21000 Dijon, France; Inserm Unit 1231, 21000 Dijon, France; Unité Fonctionnelle Innovation en Diagnostic génomique des maladies rares, FHU-TRANSLAD, Dijon University Hospital, 21000 Dijon, France; Reference Center for Rare Diseases "Déficiences intellectuelles de causes rares", Dijon University Hospital, 21000 Dijon, France
| | - Laurence Duplomb
- Université de Bourgogne, 21000 Dijon, France; Inserm Unit 1231, 21000 Dijon, France
| | - Heng Wang
- DDC Clinic for Special Needs Children, Middlefield, OH 44062, USA
| | - Muhammad Ansar
- Jules Gonin Eye Hospital, University of Lausanne, CH-1015 Lausanne, Switzerland; Advanced Molecular Genetics and Genomics Disease Research and Treatment Centre, Dow University of Health Sciences, Karachi, Pakistan
| | - Laurence Faivre
- Université de Bourgogne, 21000 Dijon, France; Inserm Unit 1231, 21000 Dijon, France; Reference Center for Rare Diseases "Anomalies du Développement et syndromes malformatifs", Dijon University Hospital, 21000 Dijon, France
| | - Nicolas Navarro
- Biogéosciences, UMR 6282 CNRS, EPHE, Université de Bourgogne, 21000 Dijon, France; EPHE, PSL University, Paris 75014, France
| | - Shilpi Minocha
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi (IITD), Hauz Khas, New Delhi 110016, India
| | - Stephan C Collins
- Université de Bourgogne, 21000 Dijon, France; Inserm Unit 1231, 21000 Dijon, France
| | - Binnaz Yalcin
- Université de Bourgogne, 21000 Dijon, France; Inserm Unit 1231, 21000 Dijon, France.
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Kang L, Ma Y, Zhao P. Deletion as novel variants in VPS13B gene in Cohen syndrome: Case series. Transl Neurosci 2023; 14:20220304. [PMID: 37692084 PMCID: PMC10487392 DOI: 10.1515/tnsci-2022-0304] [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: 05/15/2023] [Revised: 07/29/2023] [Accepted: 08/10/2023] [Indexed: 09/12/2023] Open
Abstract
Background Cohen syndrome (OMIM No. # 216550) is a rare autosomal recessive disorder caused by homozygous mutation in the vacuolar protein sorting 13 homolog B (VPS13B) gene on chromosome 8q22.2. Clinical manifestations include hypermobile joints, microcephaly, intellectual disabilities, craniofacial and limb anomalies, and neutropenia. To date, more than 200 mutations of VPS13B have been reported in over 1,000 Cohen syndrome patients. This article reviews the clinical data of two cases of Cohen syndrome diagnosed by whole exome sequencing. Results Both children visited for psychomotor retardation. Gene detection showed a mutation in 8q22.2, NM_017890.4 Intron38 c.6940+1G > T and heterozygotic deletion of exon 3-19 of the VPS13B gene (Case 1), and a mutation in 8q22.2, NM_017890.4 Intron38 c.6940+1G > T and 8q22, NM_017890.4 Exon56 c10334_10335del in the VPS13B gene (Case 2). The variation was predicted to be pathogenic by related software, and they have not been reported. Conclusion Cohen syndrome should be considered in the differential diagnosis of any child with developmental retardation and neutropenia. The present study increases the mutation spectrum of the VPS13B gene and could be helpful in genetic diagnosis and genetic counseling in Cohen syndrome patients.
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Affiliation(s)
- Li Kang
- Department of Rehabilitation Medicine, Tianjin Children’s Hospital, 238 Longyan Road, Rui Jing District, Tianjin, 300134, China
| | - Yixuan Ma
- Division of Sports Science and Physical Education, Tsinghua University, Beijing100081, China
| | - Peng Zhao
- Department of Rehabilitation Medicine, Tianjin Children’s Hospital, 238 Longyan Road, Rui Jing District, Tianjin, 300134, China
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Cai SY, Li P, Hu SX, Cai HQ, Li WJ, Peng GL. Cohen syndrome due to a novel VPS13B mutation in a Chinese family. JOURNAL OF NEURORESTORATOLOGY 2022. [DOI: 10.1016/j.jnrt.2022.100003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Hu X, Huang T, Liu Y, Zhang L, Zhu L, Peng X, Zhang S. Identification of a Novel VPS13B Mutation in a Chinese Patient with Cohen Syndrome by Whole-Exome Sequencing. Pharmgenomics Pers Med 2021; 14:1583-1589. [PMID: 34898996 PMCID: PMC8657012 DOI: 10.2147/pgpm.s327252] [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: 07/02/2021] [Accepted: 11/10/2021] [Indexed: 12/02/2022] Open
Abstract
Objective The present study aims to investigate the clinical features and diagnostic characteristics of children with Cohen syndrome caused by the vacuolar protein sorting 13 homolog B (VPS13B) gene mutation and to review the relevant literature to provide a reference for genetic counseling and the diagnosis of Cohen syndrome. Methods The clinical data and molecular genetic test results of a child with Cohen syndrome were retrospectively analyzed and a review of the relevant literature was conducted. Results A two-year-and-four-month-old boy was referred to the hospital for recurrent fever and shortness of breath. On physical examination, the boy was found to have growth retardation, thick bushy hair, microcephaly, hypertelorism, down-slanting palpebral fissures, and hypotonia. Genetic testing was performed, and the results suggested the presence of exon 20–32 heterozygous deletion and c.8275 delC (p.R2759 fs*18) heterozygous variant on the VPS13B gene from phenotypically normal parents. These two mutation loci have not been reported in the literature, and they were predicted by relevant software to be pathogenic variants. Conclusion We identified two novel variants in the VPS13B gene (exon 20–32 heterozygous deletion and c.8275 delC heterozygous variant) in a boy with Cohen syndrome, thus extending the spectrum of VPS13B gene variants in patients with Cohen syndrome.
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Affiliation(s)
- Xiaoyun Hu
- Department of Pediatrics, The First Affiliated Hospital of Nanchang University, Nanchang, People's Republic of China
| | - Tao Huang
- Department of Pediatrics, The First Affiliated Hospital of Nanchang University, Nanchang, People's Republic of China
| | - Yun Liu
- Department of Pediatrics, The First Affiliated Hospital of Nanchang University, Nanchang, People's Republic of China
| | - Lina Zhang
- Department of Pediatrics, The First Affiliated Hospital of Nanchang University, Nanchang, People's Republic of China
| | - Li Zhu
- Department of Pediatrics, The First Affiliated Hospital of Nanchang University, Nanchang, People's Republic of China
| | - Xiaohong Peng
- Department of Pediatrics, The First Affiliated Hospital of Nanchang University, Nanchang, People's Republic of China
| | - Sufang Zhang
- Department of Pediatrics, The First Affiliated Hospital of Nanchang University, Nanchang, People's Republic of China
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Ghzawi A, Hirbawi H, Negida A, Abu-Farsakh H. A case of a Jordanian male twin with Cohen's syndrome, with genetic analysis and muscle biopsy; case report. Ann Med Surg (Lond) 2021; 71:103014. [PMID: 34840762 PMCID: PMC8606835 DOI: 10.1016/j.amsu.2021.103014] [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: 08/03/2021] [Revised: 10/31/2021] [Accepted: 10/31/2021] [Indexed: 11/24/2022] Open
Abstract
Introduction and importance Cohen's syndrome is a rare autosomal recessive developmental disorder. It usually presents with a wide variety of muscular, neurological and ophthalmological clinical features. In this report, we present a rare case of the first Jordanian male identical twin with Cohen syndrome with the first ever muscle biopsy results reported. Case presentation A 20 months old identical male twins were presented for follow up with history of Salam seaziure, muscle dystocia and signs of development delay since five months old. A muscle biopsy and genetic analysis were done accordingly. Under light microscopy, the H&E and Trichome stains sections showed muscle fibers with minimal variation in muscle fiber size. No muscular degeneration, fat replacement, or fibrosis in the periendomysial area. Increased fibroblasts proliferation was seen in between the muscle fibers. The Dystrophy panel including Dystrophin, Dysferlin, Adhalin (alpha 1 sacroglycan) and Emerin showed a normal staining pattern. The heterozygous mutation pattern seen in the vacuolar protein sorting 13 homolog B (VPS13B) gene is a pathogenic variant of Cohen syndrome. The diagnosis was done accordingly. Conclusion To the best of our knowledge, this is the first case report of Cohen's syndrome from the Jordanian population, and the first muscle biopsy report in a Cohen's syndrome patient ever. This makes a unique educational report and a good guidance for future research in this concern. Cohen's syndrome is a rare autosomal recessive developmental disorder. Cohen's syndrome is a rare genetic disorder that presents with developmental delay, intellectual disability, and eye manifestations. The usual method of testing or screening for Cohen syndrome is VPS13B next-generation sequencing.
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Affiliation(s)
- Ansam Ghzawi
- Faculty of Medicine, Yarmouk University, Irbid, Jordan
| | - Hawazen Hirbawi
- Faculty of Medicine, Jordan University of Science and Technology, Irbid, Jordan
| | - Ahmad Negida
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, UK
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Razavi A, Jafarpour H, Khosravi MR, Abbasi G, Dabbaghzadeh A. A VPS13B mutation in Cohen syndrome presented with petechiae: An unusual presentation. Clin Case Rep 2021; 9:e04492. [PMID: 34322253 PMCID: PMC8301562 DOI: 10.1002/ccr3.4492] [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: 04/08/2021] [Revised: 05/28/2021] [Accepted: 05/31/2021] [Indexed: 11/15/2022] Open
Abstract
Cohen syndrome (CS) is a rare autosomal recessive disorder. CS includes a range of clinical symptoms including retinal dystrophy and myopia. The new VPS13B mutation could cause CS-induced neutropenia and petechiae in patients with CS.
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Affiliation(s)
- Alireza Razavi
- Student Research CommitteeSchool of MedicineMazandaran University of Medical SciencesSariIran
| | - Hamed Jafarpour
- Student Research CommitteeSchool of MedicineMazandaran University of Medical SciencesSariIran
| | - Mohammad reza Khosravi
- Student Research CommitteeSchool of MedicineMazandaran University of Medical SciencesSariIran
| | - Ghazal Abbasi
- Student Research CommitteeSchool of MedicineMazandaran University of Medical SciencesSariIran
| | - Abbas Dabbaghzadeh
- Department of PediatricsSchool of MedicineBu Ali Sina HospitalMazandaran University of Medical SciencesSariIran
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Li L, Bu X, Ji Y, Tan P, Liu S. A Novel Homozygous VPS13B Splice-Site Mutation Causing the Skipping of Exon 38 in a Chinese Family With Cohen Syndrome. Front Pediatr 2021; 9:651621. [PMID: 33959574 PMCID: PMC8093766 DOI: 10.3389/fped.2021.651621] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 03/18/2021] [Indexed: 11/15/2022] Open
Abstract
Background: Cohen syndrome (CS) is a clinically heterogeneous disorder characterized by extensive phenotypic variation with autosomal recessive inheritance. VPS13B was identified to be the disease-causing gene for CS. The objectives of the present study were to screen likely pathogenic mutations of the patient with developmental delay and mental retardation, and to determinate the effect of this splice-site mutation by reverse transcription analysis. Methods: Whole exome sequencing (WES) in combination with Sanger sequencing were performed to identify the causative mutations of this CS family. Subsequently, the impact of the intronic variant on splicing was analyzed by reverse transcription and the construction of expression vector. Results: A novel homozygous splice-site mutation (c.6940+1G>T) in the VPS13B gene was identified in this proband. Sanger sequencing analysis of the cDNA demonstrated that the c.6940+1G>T variant could cause the skipping of entire exon 38, resulting in the loss of 208 nucleotides and further give rise to the generation of a premature in-frame stop codon at code 2,247. Conclusions: The homozygous VPS13B splicing variant c.6940+1G>T was co-segregated with the CS phenotypes in this family and was identified to be the cause of CS after comprehensive consideration of the clinical manifestations, genetic analysis and cDNA sequencing result.
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Affiliation(s)
- Liangshan Li
- Medical Genetic Department, The Affiliated Hospital of Qingdao University, Qingdao, China.,Department of Clinical Laboratory, Medical College of Qingdao University, Qingdao, China
| | - Xiangmao Bu
- Department of Transfusion, Qingdao Women and Children's Hospital, Qingdao, China
| | - Yuhua Ji
- Newborn Disease Screening Centre, Yantai Maternal and Child Health Hospital, Yantai, China
| | - Ping Tan
- Obstetrical Department, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Shiguo Liu
- Medical Genetic Department, The Affiliated Hospital of Qingdao University, Qingdao, China
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Functional Analysis of a Compound Heterozygous Mutation in the VPS13B Gene in a Chinese Pedigree with Cohen Syndrome. J Mol Neurosci 2020; 71:943-952. [PMID: 33025479 DOI: 10.1007/s12031-020-01713-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Accepted: 09/15/2020] [Indexed: 10/23/2022]
Abstract
Cohen syndrome (CS) is an autosomal recessive congenital disorder characterized by mutation in the vacuolar protein sorting 13 homolog B (VPS13B; formerly COH1) gene. In the current study, a Chinese family has two young sibling cases having a developmental delay, physical obesity, high myopia, and a special face, which suspected to be CS. The purpose of the study was to identify variants and further analyze their pathogenicity for CS. Next-generation sequencing (NGS) revealed a compound heterozygous mutation in VPS13B gene in the proband, which comprises a frameshift mutation in NM_017890.4: c.10076_10077delCA (p.T3359fs*29) and a putative splice site mutation in c.6940 + 1G > T. Both Minigene assay in vitro and splicing assay in vivo confirmed that the splicing mutation in c.6940 + 1G > T generates a frameshift transcript with whole exon 38 skipping. Eventually, quantitative real-time PCR demonstrated that either of the two mutations can lead to degradation of the VPS13B gene at the transcriptional level. Functional studies of variants identified in CS patients are essential for their subsequent genetic counseling and prenatal diagnoses and could also be the start point for new therapeutic approaches, currently based only on symptomatic treatment.
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Homozygosity mapping and whole exome sequencing provide exact diagnosis of Cohen syndrome in a Saudi family. Brain Dev 2020; 42:587-593. [PMID: 32402540 DOI: 10.1016/j.braindev.2020.04.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 04/23/2020] [Accepted: 04/24/2020] [Indexed: 11/23/2022]
Abstract
BACKGROUND Cohen syndrome (CS) is a rare multi-system autosomal recessive disorder with a high prevalence in the Finnish population. Clinical features of Finnish-type CS are homogeneous, however, in non-Finnish populations, CS diagnosis is challenging due to broad phenotypic variability. METHODS We studied a consanguineous family having three affected individuals with clinical features of severe intellectual disability and global developmental delay. Clinical diagnosis of the phenotype could not be established based on the features. Therefore, whole genome SNP genotyping and whole exome sequencing (WES) were performed on DNA samples from affected and unaffected family members. RESULTS Homozygosity mapping identified a shared loss of heterozygosity region on chromosome 8q22.1-q22.3 and WES data analysis revealed an insertion-deletion (indel) mutation (c.11519_11521delCAAinsT) in the VPS13B gene. The indel is predicted to cause a frameshift resulting in a premature termination of the VPS13B protein (NP_060360.3:p.Pro3840Leufs*2). CONCLUSION VPS13B encodes a giant transmembrane protein called vacuolar protein sorting 13 homolog B. VPS13B is known to play a role in the glycosylation of Golgi proteins and in endosomal-lysosomal trafficking. Moreover, it is thought to function in vesicle mediated transport and sorting of proteins within the cell. The mechanism by which abnormalities of the VPS13B protein lead to the phenotype of CS is currently unknown. Here, in this study, we successfully established a clinical diagnosis of CS cases from a family using genomic analyses. Clinical re-examination of the patients revealed characteristic ocular abnormalities.
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Kaushik P, Mahajan N, Girimaji SC, Kumar A. Whole Exome Sequencing Identifies a Novel Homozygous Duplication Mutation in the VPS13B Gene in an Indian Family with Cohen Syndrome. J Mol Neurosci 2020; 70:1225-1228. [PMID: 32170714 DOI: 10.1007/s12031-020-01530-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 03/03/2020] [Indexed: 12/18/2022]
Abstract
Cohen syndrome (CS) is an autosomal recessive congenital disorder, characterized by hypotonia, intellectual disability, developmental delay, microcephaly, progressive retinopathy, neutropenia, truncal obesity, joint laxity, characteristic facial, ophthalmic, oral and appendage abnormalities, and an over friendly behavior. It has been linked to mutations in the VPS13B gene. The main purpose of this study was to determine the genetic cause of CS in an Indian family. Whole exome sequencing (WES) was used to identify the genetic cause of CS in the family. The WES analysis identified a homozygous novel duplication mutation c.5272dupG in the VPS13B gene, leading to formation of a truncating protein. The present study will be advantageous in genetic diagnosis and genetic counseling in CS, and increases the mutational spectrum of this gene.
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Affiliation(s)
- Pankhuri Kaushik
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, 560012, India
| | - Naresh Mahajan
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, 560012, India
| | - Satish C Girimaji
- The Department of Child and Adolescent Psychiatry, National Institute of Mental Health and Neuro Sciences, Bangalore, 560029, India
| | - Arun Kumar
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, 560012, India.
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