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Ranjan A, Alam MS, Kumar V, Kumar R, Saifullah KM, Fakih S. Spectrum of Multiple Congenital Anomalies-Hypotonia-Seizures Syndrome 3 (MCAHS3) Due to Phosphatidylinositol Glycan Biosynthesis Class T (PIGT) Gene Mutations: A Narrative Review. Cureus 2024; 16:e60737. [PMID: 38903302 PMCID: PMC11187727 DOI: 10.7759/cureus.60737] [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: 05/21/2024] [Indexed: 06/22/2024] Open
Abstract
Multiple congenital anomalies-hypotonia-seizures syndrome 3 (MCAHS3) results from mutations in the phosphatidylinositol glycan biosynthesis class T (PIGT) gene leading to defects in glycosylphosphatidylinositol transamidase complex (GPI-TA) synthesis. Glycosylphosphatidylinositol serves as an anchor to more than 150 mammalian proteins for attachment on cell surfaces, enabling specific functional properties. Mutations in the PIGT gene result in disruption of this extremely important post-translational protein modification, yielding dysfunctional proteins leading to MCAHS3. An exhaustive literature search was conducted across various electronic databases to reveal only 41 reported cases of MCAHS3 worldwide, emphasizing the rarity of this condition. Multiple congenital anomalies-hypotonia-seizures syndrome 3 has been reported as secondary to 18 different known PIGT variants to date, manifesting as a varying spectrum of craniofacial dysmorphism, developmental delay with epilepsy, cardiac and renal malformations, and unique features in biochemical testing and neuroimaging. This review aims to highlight the constellation of clinical symptoms, diagnostic modalities, and management challenges associated with MCAHS3 cases. It would help determine optimal diagnostic and treatment strategies for newly identified cases and facilitate new research on this rare condition.
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Affiliation(s)
- Ankit Ranjan
- Department of Neonatology, Rani Hospital, Ranchi, IND
| | | | - Vinod Kumar
- Department of Neonatology, Rani Hospital, Ranchi, IND
| | - Rajesh Kumar
- Department of Neonatology, Rani Hospital, Ranchi, IND
| | | | - Sofia Fakih
- Department of Neonatology, Rani Hospital, Ranchi, IND
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2
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Li D. Structure and Function of the Glycosylphosphatidylinositol Transamidase, a Transmembrane Complex Catalyzing GPI Anchoring of Proteins. Subcell Biochem 2024; 104:425-458. [PMID: 38963495 DOI: 10.1007/978-3-031-58843-3_16] [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] [Indexed: 07/05/2024]
Abstract
Glycosylphosphatidylinositol (GPI) anchoring of proteins is a ubiquitous posttranslational modification in eukaryotic cells. GPI-anchored proteins (GPI-APs) play critical roles in enzymatic, signaling, regulatory, and adhesion processes. Over 20 enzymes are involved in GPI synthesis, attachment to client proteins, and remodeling after attachment. The GPI transamidase (GPI-T), a large complex located in the endoplasmic reticulum membrane, catalyzes the attachment step by replacing a C-terminal signal peptide of proproteins with GPI. In the last three decades, extensive research has been conducted on the mechanism of the transamidation reaction, the components of the GPI-T complex, the role of each subunit, and the substrate specificity. Two recent studies have reported the three-dimensional architecture of GPI-T, which represent the first structures of the pathway. The structures provide detailed mechanisms for assembly that rationalizes previous biochemical results and subunit-dependent stability data. While the structural data confirm the catalytic role of PIGK, which likely uses a caspase-like mechanism to cleave the proproteins, they suggest that unlike previously proposed, GPAA1 is not a catalytic subunit. The structures also reveal a shared cavity for GPI binding. Somewhat unexpectedly, PIGT, a single-pass membrane protein, plays a crucial role in GPI recognition. Consistent with the assembly mechanisms and the active site architecture, most of the disease mutations occur near the active site or the subunit interfaces. Finally, the catalytic dyad is located ~22 Å away from the membrane interface of the GPI-binding site, and this architecture may confer substrate specificity through topological matching between the substrates and the elongated active site. The research conducted thus far sheds light on the intricate processes involved in GPI anchoring and paves the way for further mechanistic studies of GPI-T.
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Affiliation(s)
- Dianfan Li
- CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences (CAS), Shanghai, China.
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3
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Ben Ayed I, Jallouli O, Murakami Y, Souissi A, Mallouli S, Bouzid A, Kamoun F, Elloumi I, Frikha F, Tlili A, Weckhuysen S, Kinoshita T, Triki CC, Masmoudi S. Case report: Functional analysis of the p.Arg507Trp variant of the PIGT gene supporting the moderate epilepsy phenotype of mutations in the C-terminal region. Front Neurol 2023; 14:1092887. [PMID: 36970549 PMCID: PMC10034188 DOI: 10.3389/fneur.2023.1092887] [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: 12/20/2022] [Accepted: 02/01/2023] [Indexed: 03/29/2023] Open
Abstract
Pathogenic germline variants in the PIGT gene are associated with the "multiple congenital anomalies-hypotonia-seizures syndrome 3" (MCAHS3) phenotype. So far, fifty patients have been reported, most of whom suffer from intractable epilepsy. Recently, a comprehensive analysis of a cohort of 26 patients with PIGT variants has broadened the phenotypical spectrum and indicated that both p.Asn527Ser and p.Val528Met are associated with a milder epilepsy phenotype and less severe outcomes. Since all reported patients are of Caucasian/Polish origin and most harbor the same variant (p.Val528Met), the ability to draw definitive conclusions regarding the genotype-phenotype correlation remains limited. We report a new case with a homozygous variant p.Arg507Trp in the PIGT gene, detected on clinical exome sequencing. The North African patient in question displays a predominantly neurological phenotype with global developmental delay, hypotonia, brain abnormalities, and well-controlled epileptic seizures. Homozygous and heterozygous variants in codon 507 have been reported to cause PIGT deficiency without biochemical confirmation. In this study, FACS analysis of knockout HEK293 cells that had been transfected with wild-type or mutant cDNA constructs demonstrated that the p.Arg507Trp variant leads to mildly reduced activity. Our result confirm the pathogenicity of this variant and strengthen recently reported evidence on the genotype-phenotype correlation of the PIGT variant.
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Affiliation(s)
- Ikhlas Ben Ayed
- Laboratory of Molecular and Cellular Screening Processes (LPCMC), Center of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
- Medical Genetics Department, University Hedi Chaker Hospital of Sfax, Sfax, Tunisia
| | - Olfa Jallouli
- Child Neurology Department, University Hedi Chaker Hospital of Sfax, Sfax, Tunisia
- Research Laboratory “Neuropédiatrie” LR19ES15, Sfax University, Sfax, Tunisia
| | - Yoshiko Murakami
- Laboratory of Immunoglycobiology, Research Institute for Microbial Diseases, Osaka University, Suita, Japan
| | - Amal Souissi
- Laboratory of Molecular and Cellular Screening Processes (LPCMC), Center of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Salma Mallouli
- Child Neurology Department, University Hedi Chaker Hospital of Sfax, Sfax, Tunisia
- Research Laboratory “Neuropédiatrie” LR19ES15, Sfax University, Sfax, Tunisia
| | - Amal Bouzid
- Laboratory of Molecular and Cellular Screening Processes (LPCMC), Center of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Fatma Kamoun
- Child Neurology Department, University Hedi Chaker Hospital of Sfax, Sfax, Tunisia
- Research Laboratory “Neuropédiatrie” LR19ES15, Sfax University, Sfax, Tunisia
| | - Ines Elloumi
- Laboratory of Molecular and Cellular Screening Processes (LPCMC), Center of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Fakher Frikha
- Laboratory of Molecular and Cellular Screening Processes (LPCMC), Center of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Abdelaziz Tlili
- Department of Applied Biology, College of Sciences, University of Sharjah, Sharjah, United Arab Emirates
- Human Genetics and Stem Cell Laboratory, Research Institute of Sciences and Engineering, University of Sharjah, Sharjah, United Arab Emirates
| | | | - Taroh Kinoshita
- Laboratory of Immunoglycobiology, Research Institute for Microbial Diseases, Osaka University, Suita, Japan
- Center for Infectious Disease Education and Research, Osaka University, Suita, Japan
| | - Chahnez Charfi Triki
- Child Neurology Department, University Hedi Chaker Hospital of Sfax, Sfax, Tunisia
- Research Laboratory “Neuropédiatrie” LR19ES15, Sfax University, Sfax, Tunisia
| | - Saber Masmoudi
- Laboratory of Molecular and Cellular Screening Processes (LPCMC), Center of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
- *Correspondence: Saber Masmoudi
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4
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Ronzoni L, Boito S, Meossi C, Cesaretti C, Rinaldi B, Agolini E, Rizzuti T, Pezzoli L, Silipigni R, Novelli A, Iascone M, Persico N, Natacci F. Prenatal ultrasound findings associated with PIGW variants: One more piece in the FRYNS syndrome puzzle? PIGW-related prenatal findings. Prenat Diagn 2022; 42:1493-1502. [PMID: 35788948 DOI: 10.1002/pd.6204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 06/15/2022] [Accepted: 06/27/2022] [Indexed: 01/27/2023]
Abstract
OBJECTIVE We describe the prenatal ultrasound findings and autopsy of three fetuses with multiple congenital anomalies (MCA) whose diagnostic workup suggested the same genetic etiology. We conducted a literature review to corroborate the molecular results and find evidence that the identified variants are responsible for the phenotype seen. METHODS Trio-based Exome Sequencing (ES) analysis was performed on chorionic villus samples. We reviewed available reports dealing with prenatal manifestations of genes involved in the Glycosylphosphatidylinositols (GPI) biosynthesis defects (GPIBDs). RESULTS Prenatal findings shared by all the three pregnancies included facial dysmorphisms, brain malformations of the posterior fossa, skeletal and genitourinary anomalies. ES analysis identified homozygous variants of uncertain significance in PIGW in the three fetuses. Prenatal findings of the three pregnancies overlapped with those previously described for PIGW variants and with those associated with PIGN, PIGV and PIGA variants. CONCLUSION Based on the phenotypic overlap between the prenatal findings in our three cases and other cases with pathogenic variants in other genes involved in GPIBDs, we speculate that the variants identified in the three fetuses are likely causal of their phenotype and that the PIGWclinical spectrum might extend to MCA, mainly involving brain, skeletal and genitourinary systems. Moreover, we suggest that also PIGW could be involved in Fryns/Fryns-like phenotypes.
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Affiliation(s)
- Luisa Ronzoni
- Clinical Genetics Unit, Fondazione IRCCS Ca' Granda Ospedale Policlinico di Milano, Milan, Italy
| | - Simona Boito
- Fetal Medicine and Surgery Service, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Camilla Meossi
- Clinical Genetics Unit, Fondazione IRCCS Ca' Granda Ospedale Policlinico di Milano, Milan, Italy
| | - Claudia Cesaretti
- Clinical Genetics Unit, Fondazione IRCCS Ca' Granda Ospedale Policlinico di Milano, Milan, Italy
| | - Berardo Rinaldi
- Clinical Genetics Unit, Fondazione IRCCS Ca' Granda Ospedale Policlinico di Milano, Milan, Italy
| | - Emanuele Agolini
- Laboratory of Medical Genetics, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Tommaso Rizzuti
- Division of Pathology, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Laura Pezzoli
- Laboratory of Medical Genetics, ASST Papa Giovanni XXIII, Bergamo, Italy
| | - Rosamaria Silipigni
- Laboratory of Medical Genetics, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Antonio Novelli
- Laboratory of Medical Genetics, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Maria Iascone
- Laboratory of Medical Genetics, ASST Papa Giovanni XXIII, Bergamo, Italy
| | - Nicola Persico
- Fetal Medicine and Surgery Service, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Federica Natacci
- Clinical Genetics Unit, Fondazione IRCCS Ca' Granda Ospedale Policlinico di Milano, Milan, Italy
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5
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Jing W, Pilato JL, Kay C, Feng S, Tuipulotu DE, Mathur A, Shen C, Ngo C, Zhao A, Miosge LA, Ali SA, Gardiner EE, Awad MM, Lyras D, Robertson AAB, Kaakoush NO, Man SM. Clostridium septicum α-toxin activates the NLRP3 inflammasome by engaging GPI-anchored proteins. Sci Immunol 2022; 7:eabm1803. [PMID: 35594341 DOI: 10.1126/sciimmunol.abm1803] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Clostridium species are a group of Gram-positive bacteria that cause diseases in humans, such as food poisoning, botulism, and tetanus. Here, we analyzed 10 different Clostridium species and identified that Clostridium septicum, a pathogen that causes sepsis and gas gangrene, activates the mammalian cytosolic inflammasome complex in mice and humans. Mechanistically, we demonstrate that α-toxin secreted by C. septicum binds to glycosylphosphatidylinositol (GPI)-anchored proteins on the host plasma membrane, oligomerizing and forming a membrane pore that is permissive to efflux of magnesium and potassium ions. Efflux of these cytosolic ions triggers the activation of the innate immune sensor NLRP3, inducing activation of caspase-1 and gasdermin D, secretion of the proinflammatory cytokines interleukin-1β and interleukin-18, pyroptosis, and plasma membrane rupture via ninjurin-1. Furthermore, α-toxin of C. septicum induces rapid inflammasome-mediated lethality in mice and pharmacological inhibition of the NLRP3 inflammasome using MCC950 prevents C. septicum-induced lethality. Overall, our results reveal that cytosolic innate sensing of α-toxin is central to the recognition of C. septicum infection and that therapeutic blockade of the inflammasome pathway may prevent sepsis and death caused by toxin-producing pathogens.
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Affiliation(s)
- Weidong Jing
- Division of Immunity, Inflammation and Infection, The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Jordan Lo Pilato
- Division of Immunity, Inflammation and Infection, The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Callum Kay
- Division of Immunity, Inflammation and Infection, The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Shouya Feng
- Division of Immunity, Inflammation and Infection, The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Daniel Enosi Tuipulotu
- Division of Immunity, Inflammation and Infection, The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Anukriti Mathur
- Division of Immunity, Inflammation and Infection, The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Cheng Shen
- Division of Immunity, Inflammation and Infection, The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Chinh Ngo
- Division of Immunity, Inflammation and Infection, The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Anyang Zhao
- Division of Immunity, Inflammation and Infection, The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Lisa A Miosge
- Division of Immunity, Inflammation and Infection, The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Sidra A Ali
- Division of Genome Science and Cancer, The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Elizabeth E Gardiner
- Division of Genome Science and Cancer, The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
| | - Milena M Awad
- Infection and Immunity Program and Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Dena Lyras
- Infection and Immunity Program and Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Australia
| | - Avril A B Robertson
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | | | - Si Ming Man
- Division of Immunity, Inflammation and Infection, The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
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6
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Xu Y, Jia G, Li T, Zhou Z, Luo Y, Chao Y, Bao J, Su Z, Qu Q, Li D. Molecular insights into biogenesis of glycosylphosphatidylinositol anchor proteins. Nat Commun 2022; 13:2617. [PMID: 35551457 PMCID: PMC9098846 DOI: 10.1038/s41467-022-30250-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 04/22/2022] [Indexed: 02/08/2023] Open
Abstract
Eukaryotic cells are coated with an abundance of glycosylphosphatidylinositol anchor proteins (GPI-APs) that play crucial roles in fertilization, neurogenesis, and immunity. The removal of a hydrophobic signal peptide and covalent attachment of GPI at the new carboxyl terminus are catalyzed by an endoplasmic reticulum membrane GPI transamidase complex (GPI-T) conserved among all eukaryotes. Here, we report the cryo-electron microscopy (cryo-EM) structure of the human GPI-T at a global 2.53-Å resolution, revealing an equimolar heteropentameric assembly. Structure-based mutagenesis suggests a legumain-like mechanism for the recognition and cleavage of proprotein substrates, and an endogenous GPI in the structure defines a composite cavity for the lipid substrate. This elongated active site, stemming from the membrane and spanning an additional ~22-Å space toward the catalytic dyad, is structurally suited for both substrates which feature an amphipathic pattern that matches this geometry. Our work presents an important step towards the mechanistic understanding of GPI-AP biosynthesis. GPI-T catalyzes the committed step in GPI anchor protein biogenesis. Here, Xu et al. report the cryo-EM structure of the human GPI-T, revealing critical elements within an elongated, shared active site which is topologically arranged for substrate specificity.
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Affiliation(s)
- Yidan Xu
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of CAS, Chinese Academy of Sciences (CAS), 320 Yueyang Road, 200030, Shanghai, China
| | - Guowen Jia
- State Key Laboratory of Biotherapy and Cancer Center, Department of Geriatrics and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, 610044, Chengdu, China
| | - Tingting Li
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of CAS, Chinese Academy of Sciences (CAS), 320 Yueyang Road, 200030, Shanghai, China
| | - Zixuan Zhou
- Shanghai Stomatological Hospital, School of Stomatology, Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Department of Systems Biology for Medicine, Fudan University, 200032, Shanghai, China
| | - Yitian Luo
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of CAS, Chinese Academy of Sciences (CAS), 320 Yueyang Road, 200030, Shanghai, China.,School of Life Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, 201210, Shanghai, China
| | - Yulin Chao
- Shanghai Stomatological Hospital, School of Stomatology, Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Department of Systems Biology for Medicine, Fudan University, 200032, Shanghai, China
| | - Juan Bao
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of CAS, Chinese Academy of Sciences (CAS), 320 Yueyang Road, 200030, Shanghai, China
| | - Zhaoming Su
- State Key Laboratory of Biotherapy and Cancer Center, Department of Geriatrics and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, 610044, Chengdu, China.
| | - Qianhui Qu
- Shanghai Stomatological Hospital, School of Stomatology, Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Department of Systems Biology for Medicine, Fudan University, 200032, Shanghai, China.
| | - Dianfan Li
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of CAS, Chinese Academy of Sciences (CAS), 320 Yueyang Road, 200030, Shanghai, China.
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7
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Structure of human glycosylphosphatidylinositol transamidase. Nat Struct Mol Biol 2022; 29:203-209. [DOI: 10.1038/s41594-022-00726-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 01/11/2022] [Indexed: 01/31/2023]
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8
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Paprocka J, Hutny M, Hofman J, Tokarska A, Kłaniewska M, Szczałuba K, Stembalska A, Jezela-Stanek A, Śmigiel R. Spectrum of Neurological Symptoms in Glycosylphosphatidylinositol Biosynthesis Defects: Systematic Review. Front Neurol 2022; 12:758899. [PMID: 35058872 PMCID: PMC8763846 DOI: 10.3389/fneur.2021.758899] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Accepted: 11/15/2021] [Indexed: 11/13/2022] Open
Abstract
Background: Mutations of genes involved in the synthesis of glycosylphosphatidylinositol and glycosylphosphatidylinositol-anchored proteins lead to rare syndromes called glycosylphosphatidylinositol-anchored proteins biosynthesis defects. Alterations of their structure and function in these disorders impair often fundamental processes in cells, resulting in severe clinical image. This study aimed to provide a systematic review of GPIBD cases reports published in English-language literature. Methods: The browsing of open-access databases (PubMed, PubMed Central. and Medline) was conducted, followed by statistical analysis of gathered information concerning neurological symptomatology. The inclusion criteria were: studies on humans, age at onset (<18 y.o.), and report of GPIBD cases with adequate data on the genetic background and symptomatology. Exclusion criteria were: publication type (manuscripts, personal communication, review articles); reports of cases of GPI biosynthesis genes mutations in terms of other disorders; reports of GPIBD cases concentrating on non-neurological symptoms; or articles concentrating solely on the genetic issues of GPI biosynthesis. Risk of bias was assessed using Joanna Brigs Institute Critical Appraisal Checklists. Data synthesis was conducted using STATISTICA 13.3.721.1 (StatSoft Polska Sp. z.o.o.). Used tests were chi-square, Fisher's exact test (for differences in phenotype), and Mann-Whitney U test (for differences in onset of developmental delay). Results: Browsing returned a total of 973 articles which, after ruling out the repetitions and assessing the inclusion and exclusion criteria, led to final inclusion of 77 articles (337 GPIBD cases) in the analysis. The main outcomes were prevalence of neurological symptoms, onset and semiology of seizures and their response to treatment, and onset of developmental delay. Based on this data a synthesis of phenotypical differences between the groups of GPIBD cases and the general GPIBD cases population was made. Discussion: A synthetical analysis of neurological components in clinical image of GPIBD patients was presented. It highlights the main features of these disorders, which might be useful in clinical practice for consideration in differential diagnosis with children presenting with early-onset seizures and developmental delay. The limitation of this review is the scarcity of the specific data in some reports, concerning the semiology and onset of two main features of GPIBD.
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Affiliation(s)
- Justyna Paprocka
- Department of Pediatric Neurology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Katowice, Poland
| | - Michał Hutny
- Students' Scientific Society, Department of Pediatric Neurology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Katowice, Poland
| | - Jagoda Hofman
- Students' Scientific Society, Department of Pediatric Neurology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Katowice, Poland
| | - Agnieszka Tokarska
- Department of Pediatrics and Developmental Age Neurology, Upper Silesian Child Health Centre, Katowice, Poland
| | | | - Krzysztof Szczałuba
- Department of Medical Genetics, Medical University of Warsaw, Warsaw, Poland
| | | | - Aleksandra Jezela-Stanek
- Department of Genetics and Clinical Immunology, National Institute of Tuberculosis and Lung Diseases, Warsaw, Poland
| | - Robert Śmigiel
- Department of Pediatrics, Medical University of Wroclaw, Wroclaw, Poland
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9
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Bayat A, Pendziwiat M, Obersztyn E, Goldenberg P, Zacher P, Döring JH, Syrbe S, Begtrup A, Borovikov A, Sharkov A, Karasińska A, Giżewska M, Mitchell W, Morava E, Møller RS, Rubboli G. Deep-Phenotyping the Less Severe Spectrum of PIGT Deficiency and Linking the Gene to Myoclonic Atonic Seizures. Front Genet 2021; 12:663643. [PMID: 34046058 PMCID: PMC8148046 DOI: 10.3389/fgene.2021.663643] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 03/29/2021] [Indexed: 11/13/2022] Open
Abstract
The two aims of this study were (i) to describe and expand the phenotypic spectrum of PIGT deficiency in affected individuals harboring the c.1582G>A; p.Val528Met or the c.1580A > G; p.Asn527Ser variant in either homozygous or compound heterozygous state, and (ii) to identify potential genotype-phenotype correlations and any differences in disease severity among individuals with and without the PIGT variants. The existing literature was searched to identify individuals with and without the two variants. A detailed phenotypic assessment was performed of 25 individuals (both novel and previously published) with the two PIGT variants. We compared severity of disease between individuals with and without these PIGT variants. Twenty-four individuals carried the PIGT variant Val528Met in either homozygous or compound heterozygous state, and one individual displayed the Asn527Ser variant in a compound heterozygous state. Disease severity in the individual with the Asn527Ser variant was compatible with that in the individuals harboring the Val528Met variant. While individuals without the Asn527Ser or Val528Met variant had focal epilepsy, profound developmental delay (DD), and risk of premature death, those with either of the two variants had moderate to severe DD and later onset of epilepsy with both focal and generalized seizures. Individuals homozygous for the Val528Met variant generally became seizure-free on monotherapy with antiepileptic drugs, compared to other PIGT individuals who were pharmaco-resistant. Two patients were diagnosed with myoclonic-atonic seizures, and a single patient was diagnosed with eyelid myoclonia. Our comprehensive analysis of this large cohort of previously published and novel individuals with PIGT variants broadens the phenotypical spectrum and shows that both Asn527Ser and Val528Met are associated with a milder phenotype and less severe outcome. Our data show that PIGT is a new candidate gene for myoclonic atonic epilepsy. Our genotype-phenotype correlation will be useful for future genetic counseling. Natural history studies of this mild spectrum of PIGT-related disorder may shed light on hitherto unknown aspects of this rare disorder.
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Affiliation(s)
- Allan Bayat
- Institute for Regional Health Services, University of Southern Denmark, Odense, Denmark.,Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Centre, Dianalund, Denmark
| | - Manuela Pendziwiat
- Department of Neuropediatrics, Children's Hospital, University Medical Center Schleswig-Holstein, University of Kiel, Kiel, Germany.,Institute of Clinical Molecular Biology, Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Ewa Obersztyn
- Department of Medical Genetics, Institute of Mother and Child, Warsaw, Poland
| | - Paula Goldenberg
- Division of Medical Genetics, Massachusetts General Hospital, Boston, MA, United States
| | - Pia Zacher
- The Saxon Epilepsy Center Kleinwachau, Radeberg, Germany
| | - Jan Henje Döring
- Department of General Pediatrics, Division of Child Neurology and Inherited Metabolic Diseases, Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Steffen Syrbe
- Department of General Pediatrics, Division of Child Neurology and Inherited Metabolic Diseases, Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | | | | | - Artem Sharkov
- Veltischev Research and Clinical Institute for Pediatrics of the Pirogov Russian National Research Medical University, Moscow, Russia
| | - Aneta Karasińska
- Department of Dermatology, The Nicolas Copernicus State Hospital, Koszalin, Poland
| | - Maria Giżewska
- Department of Pediatrics, Endocrinology, Diabetology, Metabolic Diseases and Cardiology of the Developmental Age, Pomeranian Medical University, Szczecin, Poland
| | - Wendy Mitchell
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Eva Morava
- Department of Clinical Genomics, Laboratory of Medicine and Pathology, Center for Individualized Medicine, Mayo Clinic, Rochester, MN, United States
| | - Rikke S Møller
- Institute for Regional Health Services, University of Southern Denmark, Odense, Denmark.,Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Centre, Dianalund, Denmark
| | - Guido Rubboli
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Centre, Dianalund, Denmark.,Department of Clinical Medicine, Faculty of Medical and Health Sciences, University of Copenhagen, Copenhagen, Denmark
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10
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Sai Chandar D, Krishna Chaithanya B, Prashanthi M. Homozygous Phosphatidylinositol Glycan Class T Mutation in an Indian Girl With Multiple Congenital Anomalies-Hypotonia-Seizures Syndrome 3. Cureus 2021; 13:e14727. [PMID: 34084664 PMCID: PMC8163346 DOI: 10.7759/cureus.14727] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Multiple congenital anomalies-hypotonia-seizures syndrome 3 (MCAHS3) is a rare genetic disorder, characterized by infantile-onset epilepsy, hypotonia, global developmental delay, dysmorphic features, and variable congenital anomalies involving the cardiac, skeletal, and genitourinary systems. It is caused by the homozygous or compound heterozygous mutation in the phosphatidylinositol glycan class T (PIGT) gene. Only fewer cases were reported in the literature till now. We described a PIGT mutation in an Indian girl with global developmental delay, infantile-onset seizures, hypotonia, and facial dysmorphism. This case will help to expand the clinical spectrum of PIGT mutation.
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Affiliation(s)
- Dudipala Sai Chandar
- Pediatric Neurology, Star Women and Children Hospital, Karim Nagar, IND.,Pediatrics, Prathima Institute of Medical Sciences, Karim Nagar, IND
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11
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Chun MJ, Moon YS, Jang WR, Chae JH, Kwon YS. Neonatal-Onset PIGT Encephalopathy: A Rare Korean Case with Hypophosphatasia. ANNALS OF CHILD NEUROLOGY 2021. [DOI: 10.26815/acn.2021.00444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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12
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Johnstone DL, Nguyen TTM, Zambonin J, Kernohan KD, St‐Denis A, Baratang NV, Hartley T, Geraghty MT, Richer J, Majewski J, Bareke E, Guerin A, Pendziwiat M, Pena LDM, Braakman HMH, Gripp KW, Edmondson AC, He M, Spillmann RC, Eklund EA, Bayat A, McMillan HJ, Boycott KM, Campeau PM. Early infantile epileptic encephalopathy due to biallelic pathogenic variants in PIGQ: Report of seven new subjects and review of the literature. J Inherit Metab Dis 2020; 43:1321-1332. [PMID: 32588908 PMCID: PMC7689772 DOI: 10.1002/jimd.12278] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 06/21/2020] [Accepted: 06/23/2020] [Indexed: 01/18/2023]
Abstract
We investigated seven children from six families to expand the phenotypic spectrum associated with an early infantile epileptic encephalopathy caused by biallelic pathogenic variants in the phosphatidylinositol glycan anchor biosynthesis class Q (PIGQ) gene. The affected children were all identified by clinical or research exome sequencing. Clinical data, including EEGs and MRIs, was comprehensively reviewed and flow cytometry and transfection experiments were performed to investigate PIGQ function. Pathogenic biallelic PIGQ variants were associated with increased mortality. Epileptic seizures, axial hypotonia, developmental delay and multiple congenital anomalies were consistently observed. Seizure onset occurred between 2.5 months and 7 months of age and varied from treatable seizures to recurrent episodes of status epilepticus. Gastrointestinal issues were common and severe, two affected individuals had midgut volvulus requiring surgical correction. Cardiac anomalies including arrythmias were observed. Flow cytometry using granulocytes and fibroblasts from affected individuals showed reduced expression of glycosylphosphatidylinositol (GPI)-anchored proteins. Transfection of wildtype PIGQ cDNA into patient fibroblasts rescued this phenotype. We expand the phenotypic spectrum of PIGQ-related disease and provide the first functional evidence in human cells of defective GPI-anchoring due to pathogenic variants in PIGQ.
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Affiliation(s)
- Devon L. Johnstone
- Children's Hospital of Eastern Ontario Research InstituteOttawaOntarioCanada
| | | | - Jessica Zambonin
- Children's Hospital of Eastern Ontario Research InstituteOttawaOntarioCanada
- Department of GeneticsChildren's Hospital of Eastern OntarioOttawaOntarioCanada
| | - Kristin D. Kernohan
- Children's Hospital of Eastern Ontario Research InstituteOttawaOntarioCanada
- Division of Metabolics and Newborn Screening, Department of PediatricsChildren's Hospital of Eastern OntarioOttawaOntarioCanada
| | - Anik St‐Denis
- Research Center, CHU Sainte JustineUniversity of MontrealMontrealQuebecCanada
| | - Nissan V. Baratang
- Research Center, CHU Sainte JustineUniversity of MontrealMontrealQuebecCanada
| | - Taila Hartley
- Children's Hospital of Eastern Ontario Research InstituteOttawaOntarioCanada
| | - Michael T. Geraghty
- Division of Metabolics and Newborn Screening, Department of PediatricsChildren's Hospital of Eastern OntarioOttawaOntarioCanada
| | - Julie Richer
- Department of GeneticsChildren's Hospital of Eastern OntarioOttawaOntarioCanada
| | - Jacek Majewski
- Department of Human GeneticsMcGill UniversityMontrealQuebecCanada
- McGill University and Genome Quebec Innovation CentreMontrealQuebecCanada
| | - Eric Bareke
- Department of Human GeneticsMcGill UniversityMontrealQuebecCanada
- McGill University and Genome Quebec Innovation CentreMontrealQuebecCanada
| | - Andrea Guerin
- Division of Medical Genetics, Department of PediatricsQueen's UniversityKingstonOntarioCanada
| | - Manuela Pendziwiat
- Department of NeuropediatricsChristian‐Albrechts‐University of KielKielGermany
| | - Loren D. M. Pena
- Division of Human GeneticsCincinnati Children's Hospital Medical CenterCincinnatiOhioUSA
- Department of PediatricsUniversity of Cincinnati College of MedicineCincinnatiOhioUSA
| | - Hilde M. H. Braakman
- Department of NeurologyAcademic Center for Epileptology Kempenhaeghe & Maastricht University Medical CenterHeezeThe Netherlands
- Department of Pediatric Neurology, Amalia Children's HospitalRadboud University Medical Center & Donders Institute for Brain, Cognition and Behaviour, Radboud UniversityNijmegenThe Netherlands
| | - Karen W. Gripp
- Division of Medical GeneticsA. I. DuPont Hospital for Children/NemoursWilmingtonDelawareUSA
| | - Andrew C. Edmondson
- Department of Pediatrics, Division of Human GeneticsChildren's Hospital of PhiladelphiaPhiladelphiaPennsylvaniaUSA
| | - Miao He
- Department of Pathology and Laboratory MedicineChildren's Hospital of PhiladelphiaPhiladelphiaPennsylvaniaUSA
| | - Rebecca C. Spillmann
- Division of Medical Genetics, Department of PediatricsDuke University Medical CenterDurhamNorth CarolinaUSA
| | - Erik A. Eklund
- Department of Pediatric Neurology, Region Skåne and Clinical SciencesLund University Skåne University Hospital (SUS)LundSweden
| | - Allan Bayat
- Department of Genetics and Personalized MedicineDanish Epilepsy CentreDianalundDenmark
- Institute for Regional Health Services ResearchUniversity of Southern DenmarkOdenseDenmark
| | - Hugh J. McMillan
- Division of Neurology, Department of PediatricsChildren's Hospital of Eastern OntarioOttawaOntarioCanada
| | - Kym M. Boycott
- Children's Hospital of Eastern Ontario Research InstituteOttawaOntarioCanada
- Department of GeneticsChildren's Hospital of Eastern OntarioOttawaOntarioCanada
| | - Philippe M. Campeau
- Research Center, CHU Sainte JustineUniversity of MontrealMontrealQuebecCanada
- Department of Pediatrics, Sainte‐Justine HospitalUniversity of MontrealMontrealQuebecCanada
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13
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Höchsmann B, Murakami Y, Osato M, Knaus A, Kawamoto M, Inoue N, Hirata T, Murata S, Anliker M, Eggermann T, Jäger M, Floettmann R, Höllein A, Murase S, Ueda Y, Nishimura JI, Kanakura Y, Kohara N, Schrezenmeier H, Krawitz PM, Kinoshita T. Complement and inflammasome overactivation mediates paroxysmal nocturnal hemoglobinuria with autoinflammation. J Clin Invest 2020; 129:5123-5136. [PMID: 31430258 DOI: 10.1172/jci123501] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 08/16/2019] [Indexed: 12/16/2022] Open
Abstract
Patients with paroxysmal nocturnal hemoglobinuria (PNH) have a clonal population of blood cells deficient in glycosylphosphatidylinositol-anchored (GPI-anchored) proteins, resulting from a mutation in the X-linked gene PIGA. Here we report on a set of patients in whom PNH results instead from biallelic mutation of PIGT on chromosome 20. These PIGT-PNH patients have clinically typical PNH, but they have in addition prominent autoinflammatory features, including recurrent attacks of aseptic meningitis. In all these patients we find a germ-line point mutation in one PIGT allele, whereas the other PIGT allele is removed by somatic deletion of a 20q region comprising maternally imprinted genes implicated in myeloproliferative syndromes. Unlike in PIGA-PNH cells, GPI is synthesized in PIGT-PNH cells and, since its attachment to proteins is blocked, free GPI is expressed on the cell surface. From studies of patients' leukocytes and of PIGT-KO THP-1 cells we show that, through increased IL-1β secretion, activation of the lectin pathway of complement and generation of C5b-9 complexes, free GPI is the agent of autoinflammation. Eculizumab treatment abrogates not only intravascular hemolysis, but also autoinflammation. Thus, PIGT-PNH differs from PIGA-PNH both in the mechanism of clonal expansion and in clinical manifestations.
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Affiliation(s)
- Britta Höchsmann
- Institute of Transfusion Medicine, University of Ulm, Ulm, Germany.,Institute of Clinical Transfusion Medicine and Immunogenetics, German Red Cross Blood Transfusion Service and University Hospital Ulm, Ulm, Germany
| | - Yoshiko Murakami
- Research Institute for Microbial Diseases and.,WPI Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Makiko Osato
- Research Institute for Microbial Diseases and.,Department of Hematology and Oncology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Alexej Knaus
- Institute for Genomic Statistics and Bioinformatics, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Michi Kawamoto
- Department of Neurology, Kobe City Medical Center General Hospital, Kobe, Japan
| | - Norimitsu Inoue
- Department of Tumor Immunology, Osaka International Cancer Institute, Osaka, Japan
| | | | - Shogo Murata
- Research Institute for Microbial Diseases and.,Department of Hematology/Oncology, Wakayama Medical University, Wakayama, Japan
| | - Markus Anliker
- Institute of Transfusion Medicine, University of Ulm, Ulm, Germany
| | - Thomas Eggermann
- Institute for Human Genetics,Medical Faculty, RWTH University Aachen, Aachen, Germany
| | - Marten Jäger
- Department of Medical Genetics, Charite Hospital, University of Berlin, Berlin, Germany
| | - Ricarda Floettmann
- Department of Medical Genetics, Charite Hospital, University of Berlin, Berlin, Germany
| | | | - Sho Murase
- Department of Neurology, Kobe City Medical Center General Hospital, Kobe, Japan
| | - Yasutaka Ueda
- Department of Hematology and Oncology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Jun-Ichi Nishimura
- Department of Hematology and Oncology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Yuzuru Kanakura
- Department of Hematology and Oncology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Nobuo Kohara
- Department of Neurology, Kobe City Medical Center General Hospital, Kobe, Japan
| | | | - Peter M Krawitz
- Institute for Genomic Statistics and Bioinformatics, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Taroh Kinoshita
- Research Institute for Microbial Diseases and.,WPI Immunology Frontier Research Center, Osaka University, Osaka, Japan
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14
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Zhang L, Mao X, Long H, Xiao B, Luo Z, Xiao W, Jin X. Compound Heterozygous PIGS Variants Associated With Infantile Spasm, Global Developmental Delay, Hearing Loss, Visual Impairment, and Hypotonia. Front Genet 2020; 11:564. [PMID: 32612635 PMCID: PMC7308501 DOI: 10.3389/fgene.2020.00564] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 05/11/2020] [Indexed: 12/29/2022] Open
Abstract
Glycosylphosphatidylinositol (GPI) is a membrane anchor for cell surface proteins. Inherited GPI deficiencies are a new subclass of congenital disorders of glycosylation. Phosphatidylinositol glycan class S (PIGS) is a subunit of the GPI transamidase which plays important roles in many biological processes. In this study, we present a Chinese boy with infantile spasms (ISs), severe global developmental delay, hearing loss, visual impairment (cortical blindness), hypotonia, and intellectual disability and whose whole-exome sequencing (WES) identified compound heterozygous variants in PIGS (MIM:610271):c.148C > T (p.Gln50∗) and c.1141_1164dupGACATGGTGCGAGTGATGGAGGTG (p.Asp381_Val388dup). Flow cytometry analyses demonstrated that the boy with PIGS variants had a decreased expression of GPI-APs. This study stresses the importance of including the screening of PIGS gene in the case of pediatric neurological syndromes and reviews the clinical features of PIGS-associated disorders.
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Affiliation(s)
- Lily Zhang
- Neurology Department, Xiangya Hospital, Central South University, Changsha, China
| | - Xiao Mao
- Department of Medical Genetics, Maternal and Child Health Hospital of Hunan Province, Changsha, China
| | - Hongyu Long
- Neurology Department, Xiangya Hospital, Central South University, Changsha, China
| | - Bo Xiao
- Neurology Department, Xiangya Hospital, Central South University, Changsha, China
| | - Zhaohui Luo
- Neurology Department, Xiangya Hospital, Central South University, Changsha, China
| | - Wenbiao Xiao
- Neurology Department, Xiangya Hospital, Central South University, Changsha, China
| | - Xingbing Jin
- Neurosurgery Department, Xiangya Hospital, Central South University, Changsha, China
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15
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Wu T, Yin F, Guang S, He F, Yang L, Peng J. The Glycosylphosphatidylinositol biosynthesis pathway in human diseases. Orphanet J Rare Dis 2020; 15:129. [PMID: 32466763 PMCID: PMC7254680 DOI: 10.1186/s13023-020-01401-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 05/06/2020] [Indexed: 01/15/2023] Open
Abstract
Glycosylphosphatidylinositol biosynthesis defects cause rare genetic disorders characterised by developmental delay/intellectual disability, seizures, dysmorphic features, and diverse congenital anomalies associated with a wide range of additional features (hypotonia, hearing loss, elevated alkaline phosphatase, and several other features). Glycosylphosphatidylinositol functions as an anchor to link cell membranes and protein. These proteins function as enzymes, adhesion molecules, complement regulators, or co-receptors in signal transduction pathways. Biallelic variants involved in the glycosylphosphatidylinositol anchored proteins biosynthetic pathway are responsible for a growing number of disorders, including multiple congenital anomalies-hypotonia-seizures syndrome; hyperphosphatasia with mental retardation syndrome/Mabry syndrome; coloboma, congenital heart disease, ichthyosiform dermatosis, mental retardation, and ear anomalies/epilepsy syndrome; and early infantile epileptic encephalopathy-55. This review focuses on the current understanding of Glycosylphosphatidylinositol biosynthesis defects and the associated genes to further understand its wide phenotype spectrum.
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Affiliation(s)
- Tenghui Wu
- Department of Pediatrics, XiangYa Hospital, Central South University, 87 Xiangya Road, Changsha, 410008, Hunan Province, China.,Hunan Children's Mental Disorders Research Center, XiangYa Hospital, Central South University, 87 Xiangya Road, Changsha, 410008, Hunan Province, China
| | - Fei Yin
- Department of Pediatrics, XiangYa Hospital, Central South University, 87 Xiangya Road, Changsha, 410008, Hunan Province, China.,Hunan Children's Mental Disorders Research Center, XiangYa Hospital, Central South University, 87 Xiangya Road, Changsha, 410008, Hunan Province, China
| | - Shiqi Guang
- Department of Pediatrics, XiangYa Hospital, Central South University, 87 Xiangya Road, Changsha, 410008, Hunan Province, China.,Hunan Children's Mental Disorders Research Center, XiangYa Hospital, Central South University, 87 Xiangya Road, Changsha, 410008, Hunan Province, China
| | - Fang He
- Department of Pediatrics, XiangYa Hospital, Central South University, 87 Xiangya Road, Changsha, 410008, Hunan Province, China.,Hunan Children's Mental Disorders Research Center, XiangYa Hospital, Central South University, 87 Xiangya Road, Changsha, 410008, Hunan Province, China
| | - Li Yang
- Department of Pediatrics, XiangYa Hospital, Central South University, 87 Xiangya Road, Changsha, 410008, Hunan Province, China.,Hunan Children's Mental Disorders Research Center, XiangYa Hospital, Central South University, 87 Xiangya Road, Changsha, 410008, Hunan Province, China
| | - Jing Peng
- Department of Pediatrics, XiangYa Hospital, Central South University, 87 Xiangya Road, Changsha, 410008, Hunan Province, China. .,Hunan Children's Mental Disorders Research Center, XiangYa Hospital, Central South University, 87 Xiangya Road, Changsha, 410008, Hunan Province, China.
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16
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Analyzing clinical and genetic characteristics of a cohort with multiple congenital anomalies-hypotonia-seizures syndrome (MCAHS). Orphanet J Rare Dis 2020; 15:78. [PMID: 32220244 PMCID: PMC7099766 DOI: 10.1186/s13023-020-01365-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 03/18/2020] [Indexed: 12/28/2022] Open
Abstract
Objective To summarize and extend the phenotypic characterization of Multiple Congenital Anomalies-Hypotonia-Seizures Syndrome, and to discuss genotype-phenotype correlations. Methods Collecting clinical information of 17 patients with pathogenic variants in PIGN, PIGA, and PIGT. Genetic studies were performed on all patients. Results There were 7 patients with 15 PIGN mutations (one patient carrying 3 mutations), 8 patients with 8 PIGA mutations, and 2 patients with 5 PIGT mutations (one patient carrying 3 mutations). All patients had epilepsy and developmental delay, with 71% of them showed hypotonia. And among these patients’ various seizure types, the focal seizure was the most common one. Eighty-two percent patients showed a significant relationship between seizures and fever. Serum ALP was elevated in one patient with PIGN mutations and in two patients with PIGA mutations. Brain MRI showed enlarged subarachnoid space in 56% of patients. Some other different characteristics had also been found in our patients: First, atypical absence seizures presented in three patients with PIGN mutations; Second, diffuse slow waves mixed with focal or multifocal discharges of interictal EEG in 88% cases with PIGA-deficient; Third, phenotypes of seven out of eight patients with PIGA mutations were difficult to be classified as severe or less severe group; Last, mild neurological symptoms and developmental status rather than severe conditions occurred in one patient with PIGT mutations. Conclusion With epilepsy, developmental delay, and/or hypotonia as common features, the knowledge of MCAHS in terms of phenotype and genotype has been expanded. In cases with PIGN-deficient, we expanded the types of atypical absence seizures, and described one patient with elevated serum ALP. Focal seizures with diffuse slow waves mixed with focal or multifocal discharges on EEG rather than infantile spasms with hypsarrhythmia, which as previously reported were often seen in our patients with PIGA mutations. The classifications of phenotypes caused by PIGA mutations should be more continuous than discrete. The mild phenotype of one patient with PIGT mutations expanded the clinical presentation of MCAHS3.
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17
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Mierzewska H, Jezela-Stanek A. Is leucodystrophy really a feature of PIGT-CDG? Neuropathol Appl Neurobiol 2020; 46:615-616. [PMID: 32058618 DOI: 10.1111/nan.12609] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 01/03/2020] [Indexed: 11/29/2022]
Affiliation(s)
- Hanna Mierzewska
- Department of Child and Adolescent Neurology, Institute of Mother and Child, Warsaw, Poland
| | - Aleksandra Jezela-Stanek
- Department of Genetics and Clinical Immunology, National Institute of Tuberculosis and Lung Diseases, Warsaw, Poland
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18
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Knaus A, Kortüm F, Kleefstra T, Stray-Pedersen A, Đukić D, Murakami Y, Gerstner T, van Bokhoven H, Iqbal Z, Horn D, Kinoshita T, Hempel M, Krawitz PM. Mutations in PIGU Impair the Function of the GPI Transamidase Complex, Causing Severe Intellectual Disability, Epilepsy, and Brain Anomalies. Am J Hum Genet 2019; 105:395-402. [PMID: 31353022 DOI: 10.1016/j.ajhg.2019.06.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 06/07/2019] [Indexed: 12/11/2022] Open
Abstract
The glycosylphosphatidylinositol (GPI) anchor links over 150 proteins to the cell surface and is present on every cell type. Many of these proteins play crucial roles in neuronal development and function. Mutations in 18 of the 29 genes implicated in the biosynthesis of the GPI anchor have been identified as the cause of GPI biosynthesis deficiencies (GPIBDs) in humans. GPIBDs are associated with intellectual disability and seizures as their cardinal features. An essential component of the GPI transamidase complex is PIGU, along with PIGK, PIGS, PIGT, and GPAA1, all of which link GPI-anchored proteins (GPI-APs) onto the GPI anchor in the endoplasmic reticulum (ER). Here, we report two homozygous missense mutations (c.209T>A [p.Ile70Lys] and c.1149C>A [p.Asn383Lys]) in five individuals from three unrelated families. All individuals presented with global developmental delay, severe-to-profound intellectual disability, muscular hypotonia, seizures, brain anomalies, scoliosis, and mild facial dysmorphism. Using multicolor flow cytometry, we determined a characteristic profile for GPI transamidase deficiency. On granulocytes this profile consisted of reduced cell-surface expression of fluorescein-labeled proaerolysin (FLAER), CD16, and CD24, but not of CD55 and CD59; additionally, B cells showed an increased expression of free GPI anchors determined by T5 antibody. Moreover, computer-assisted facial analysis of different GPIBDs revealed a characteristic facial gestalt shared among individuals with mutations in PIGU and GPAA1. Our findings improve our understanding of the role of the GPI transamidase complex in the development of nervous and skeletal systems and expand the clinical spectrum of disorders belonging to the group of inherited GPI-anchor deficiencies.
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19
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Larsen KB, Bayat A, Møller RS, Maroun LL, Lund EL. First report of the neuropathological findings in a patient with leukodystrophy and compound heterozygous variants in the
PIGT
gene. Neuropathol Appl Neurobiol 2019; 45:732-735. [DOI: 10.1111/nan.12557] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 04/23/2019] [Indexed: 11/28/2022]
Affiliation(s)
- K. B. Larsen
- Department of Pathology University Hospital of Copenhagen Rigshospitalet Denmark
- Department of Neuropathology and Ocular Pathology John Radcliffe Hospital Oxford University Hospital Oxford UK
| | - A. Bayat
- Department of Pediatrics University Hospital of Copenhagen Rigshospitalet Denmark
- Danish Epilepsy Centre Dianalund Denmark
| | - R. S. Møller
- Danish Epilepsy Centre Dianalund Denmark
- Department of Regional Health Research University of Southern Denmark Odense Denmark
| | - L. L. Maroun
- Department of Pathology University Hospital of Copenhagen Rigshospitalet Denmark
| | - E. L. Lund
- Department of Pathology University Hospital of Copenhagen Rigshospitalet Denmark
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20
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Bayat A, Knaus A, Juul AW, Dukic D, Gardella E, Charzewska A, Clement E, Hjalgrim H, Hoffman-Zacharska D, Horn D, Horton R, Hurst JA, Josifova D, Larsen LHG, Lascelles K, Obersztyn E, Pagnamenta A, Pal DK, Pendziwiat M, Ryten M, Taylor J, Vogt J, Weber Y, Krawitz PM, Helbig I, Kini U, Møller RS. PIGT-CDG, a disorder of the glycosylphosphatidylinositol anchor: description of 13 novel patients and expansion of the clinical characteristics. Genet Med 2019; 21:2216-2223. [DOI: 10.1038/s41436-019-0512-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 03/25/2019] [Indexed: 12/20/2022] Open
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21
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Mason S, Castilla-Vallmanya L, James C, Andrews PI, Balcells S, Grinberg D, Kirk EP, Urreizti R. Case report of a child bearing a novel deleterious splicing variant in PIGT. Medicine (Baltimore) 2019; 98:e14524. [PMID: 30813157 PMCID: PMC6407924 DOI: 10.1097/md.0000000000014524] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
RATIONALE Trio family-based whole exome sequencing (WES) is a powerful tool in the diagnosis of rare neurodevelopmental diseases, even in patients with the unclear diagnosis. There have been previous reports of variants in the phosphatidylinositol glycan anchor biosynthesis class T (PIGT) gene associated with multiple congenital anomalies, with a total of 14 affected individuals across 8 families. PATIENT CONCERNS An 18-month-old boy of Greek ancestry presented with global developmental delay, generalized tonic-clonic seizures, hypotonia, renal cysts, esotropia, bilateral undescended testes, bilateral vesicoureteric reflux, marked cardiac dextroposition, bilateral talipes equinovarus, and dysmorphic features. DIAGNOSIS WES revealed 2 compound heterozygous variants in the PIGT gene, c.[494-2A>G]; [547A>C]/p.[Asp122Glyfs*35]; [Thr183Pro]. The splicing mutation was demonstrated to lead to the skipping of exon 4. INTERVENTIONS Seizures, infections, and other main symptoms were treated. OUTCOMES The patient died at 2 years of age before the molecular diagnosis was achieved. Genetic counseling has been offered to the family. LESSONS Most of the clinical features of the patient are in agreement with the previously described PIGT cases corroborating the usefulness of WES as a diagnostic tool.
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Affiliation(s)
- Samantha Mason
- Centre for Clinical Genetics, Sydney Children's Hospital Randwick, Sydney, Australia
| | - Laura Castilla-Vallmanya
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, IBUB, Institut de Recerca Sant Joan de Déu (IRSJD), CIBERER, Barcelona, Spain
| | | | | | - Susana Balcells
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, IBUB, Institut de Recerca Sant Joan de Déu (IRSJD), CIBERER, Barcelona, Spain
| | - Daniel Grinberg
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, IBUB, Institut de Recerca Sant Joan de Déu (IRSJD), CIBERER, Barcelona, Spain
| | - Edwin P. Kirk
- Centre for Clinical Genetics, Sydney Children's Hospital Randwick, Sydney, Australia
- NSW Health Pathology East, Genetics Laboratory
- School of Women's and Children's Health, University of New South Wales, Randwick, Sydney, Australia
| | - Roser Urreizti
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, IBUB, Institut de Recerca Sant Joan de Déu (IRSJD), CIBERER, Barcelona, Spain
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