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Sadamitsu K, Yanagi K, Hasegawa Y, Murakami Y, Low SE, Ooshima D, Matsubara Y, Okamoto N, Kaname T, Hirata H. A novel homozygous variant of the PIGK gene caused by paternal disomy in a patient with neurodevelopmental disorder, cerebellar atrophy, and seizures. J Hum Genet 2024:10.1038/s10038-024-01264-3. [PMID: 38902431 DOI: 10.1038/s10038-024-01264-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 05/27/2024] [Accepted: 05/30/2024] [Indexed: 06/22/2024]
Abstract
Glycosylphosphatidylinositol (GPI)-anchored proteins are located at the cell surface by a covalent attachment between protein and GPI embedded in the plasma membrane. This attachment is catalyzed by GPI transamidase comprising five subunits (PIGK, PIGS, PIGT, PIGU, and GPAA1) in the endoplasmic reticulum. Loss of either subunit of GPI transamidase eliminates cell surface localization of GPI-anchored proteins. In humans, pathogenic variants in either subunit of GPI transamidase cause neurodevelopmental disorders. However, how the loss of GPI-anchored proteins triggers neurodevelopmental defects remains largely unclear. Here, we identified a novel homozygous variant of PIGK, NM_005482:c.481A > G,p. (Met161Val), in a Japanese female patient with neurodevelopmental delay, hypotonia, cerebellar atrophy, febrile seizures, hearing loss, growth impairment, dysmorphic facial features, and brachydactyly. The missense variant was found heterozygous in her father, but not in her mother. Zygosity analysis revealed that the homozygous PIGK variant in the patient was caused by paternal isodisomy. Rescue experiments using PIGK-deficient CHO cells revealed that the p.Met161Val variant of PIGK reduced GPI transamidase activity. Rescue experiments using pigk mutant zebrafish confirmed that the p.Met161Val variant compromised PIGK function in tactile-evoked motor response. We also demonstrated that axonal localization of voltage-gated sodium channels and concomitant generation of action potentials were impaired in pigk-deficient neurons in zebrafish, suggesting a link between GPI-anchored proteins and neuronal defects. Taken together, the missense p.Met161Val variant of PIGK is a novel pathogenic variant that causes the neurodevelopmental disorder.
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Affiliation(s)
- Kenichiro Sadamitsu
- Department of Chemistry and Biological Science, College of Science and Engineering, Aoyama Gakuin University, Sagamihara, 252-5258, Japan
| | - Kumiko Yanagi
- Department of Genome Medicine, National Center for Child Health and Development, Tokyo, 157-8535, Japan
| | - Yuiko Hasegawa
- Department of Medical Genetics, Osaka Women's and Children's Hospital, Izumi, 594-1101, Japan
| | - Yoshiko Murakami
- Laboratory of Immunoglycobiology, Research Institute for Microbial Diseases, Osaka University, Suita, 565-0871, Japan
| | - Sean E Low
- Department of Chemistry and Biological Science, College of Science and Engineering, Aoyama Gakuin University, Sagamihara, 252-5258, Japan
| | - Daikun Ooshima
- Department of Chemistry and Biological Science, College of Science and Engineering, Aoyama Gakuin University, Sagamihara, 252-5258, Japan
| | - Yoichi Matsubara
- National Center for Child Health and Development, Tokyo, 157-8535, Japan
| | - Nobuhiko Okamoto
- Department of Medical Genetics, Osaka Women's and Children's Hospital, Izumi, 594-1101, Japan
| | - Tadashi Kaname
- Department of Genome Medicine, National Center for Child Health and Development, Tokyo, 157-8535, Japan.
| | - Hiromi Hirata
- Department of Chemistry and Biological Science, College of Science and Engineering, Aoyama Gakuin University, Sagamihara, 252-5258, Japan.
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2
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Lee HF, Chi CS. Congenital disorders of glycosylation and infantile epilepsy. Epilepsy Behav 2023; 142:109214. [PMID: 37086590 DOI: 10.1016/j.yebeh.2023.109214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 04/01/2023] [Accepted: 04/04/2023] [Indexed: 04/24/2023]
Abstract
Congenital disorders of glycosylation (CDG) are a group of rare inherited metabolic disorders caused by defects in various defects of protein or lipid glycosylation pathways. The symptoms and signs of CDG usually develop in infancy. Epilepsy is commonly observed in CDG individuals and is often a presenting symptom. These epilepsies can present across the lifespan, share features of refractoriness to antiseizure medications, and are often associated with comorbid developmental delay, psychomotor regression, intellectual disability, and behavioral problems. In this review, we discuss CDG and infantile epilepsy, focusing on an overview of clinical manifestations and electroencephalographic features. Finally, we propose a tiered approach that will permit a clinician to systematically investigate and identify CDG earlier, and furthermore, to provide genetic counseling for the family.
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Affiliation(s)
- Hsiu-Fen Lee
- Department of Post-Baccalaureate Medicine, College of Medicine, National Chung Hsing University, 145, Xingda Rd., Taichung 402, Taiwan; Division of Pediatric Neurology, Children's Medical Center, Taichung Veterans General Hospital, 1650, Taiwan Boulevard Sec. 4, Taichung 407, Taiwan.
| | - Ching-Shiang Chi
- Division of Pediatric Neurology, Children's Medical Center, Taichung Veterans General Hospital, 1650, Taiwan Boulevard Sec. 4, Taichung 407, Taiwan.
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Mastrangelo M, Gasparri V, Bernardi K, Foglietta S, Ramantani G, Pisani F. Epilepsy Phenotypes of Vitamin B6-Dependent Diseases: An Updated Systematic Review. CHILDREN 2023; 10:children10030553. [PMID: 36980111 PMCID: PMC10047402 DOI: 10.3390/children10030553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/12/2023] [Accepted: 03/13/2023] [Indexed: 03/17/2023]
Abstract
Background: Vitamin B6-dependent epilepsies include treatable diseases responding to pyridoxine or pyridoxal-5Iphosphate (ALDH7A1 deficiency, PNPO deficiency, PLP binding protein deficiency, hyperprolinemia type II and hypophosphatasia and glycosylphosphatidylinositol anchor synthesis defects). Patients and methods: We conducted a systematic review of published pediatric cases with a confirmed molecular genetic diagnosis of vitamin B6-dependent epilepsy according to PRISMA guidelines. Data on demographic features, seizure semiology, EEG patterns, neuroimaging, treatment, and developmental outcomes were collected. Results: 497 published patients fulfilled the inclusion criteria. Seizure onset manifested at 59.8 ± 291.6 days (67.8% of cases in the first month of life). Clonic, tonic-clonic, and myoclonic seizures accounted for two-thirds of the cases, while epileptic spasms were observed in 7.6%. Burst-suppression/suppression-burst represented the most frequently reported specific EEG pattern (14.4%), mainly in PLPB, ALDH7A1, and PNPO deficiency. Pyridoxine was administered to 312 patients (18.5% intravenously, 76.9% orally, 4.6% not specified), and 180 also received antiseizure medications. Pyridoxine dosage ranged between 1 and 55 mg/kg/die. Complete seizure freedom was achieved in 160 patients, while a significant seizure reduction occurred in 38. PLP, lysine-restricted diet, and arginine supplementation were used in a small proportion of patients with variable efficacy. Global developmental delay was established in 30.5% of a few patients in whom neurocognitive tests were performed. Conclusions: Despite the wide variability, the most frequent hallmarks of the epilepsy phenotype in patients with vitamin B6-dependent seizures include generalized or focal motor seizure semiology and a burst suppression/suppression burst pattern in EEG.
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Affiliation(s)
- Mario Mastrangelo
- Child Neurology and Psychiatry Unit, Department of Human Neurosciences, Sapienza University of Rome, 00185 Rome, Italy
- Department of Neuroscience/Mental Health, Azienda Ospedaliero-Universitaria Policlinico Umberto I, 00161 Rome, Italy
- Correspondence:
| | - Valentina Gasparri
- Child Neurology and Psychiatry Unit, Department of Human Neurosciences, Sapienza University of Rome, 00185 Rome, Italy
| | - Katerina Bernardi
- Child Neurology and Psychiatry Unit, Department of Human Neurosciences, Sapienza University of Rome, 00185 Rome, Italy
| | - Silvia Foglietta
- Child Neurology and Psychiatry Unit, Department of Human Neurosciences, Sapienza University of Rome, 00185 Rome, Italy
| | - Georgia Ramantani
- Department of Neuropediatrics, University Children’s Hospital Zurich and University of Zurich, 8032 Zurich, Switzerland
| | - Francesco Pisani
- Child Neurology and Psychiatry Unit, Department of Human Neurosciences, Sapienza University of Rome, 00185 Rome, Italy
- Department of Neuroscience/Mental Health, Azienda Ospedaliero-Universitaria Policlinico Umberto I, 00161 Rome, Italy
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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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5
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Efthymiou S, Dutra-Clarke M, Maroofian R, Kaiyrzhanov R, Scala M, Reza Alvi J, Sultan T, Christoforou M, Tuyet Mai Nguyen T, Mankad K, Vona B, Rad A, Striano P, Salpietro V, Guillen Sacoto MJ, Zaki MS, Gleeson JG, Campeau PM, Russell BE, Houlden H. Expanding the phenotype of PIGS-associated early onset epileptic developmental encephalopathy. Epilepsia 2021; 62:e35-e41. [PMID: 33410539 PMCID: PMC7898547 DOI: 10.1111/epi.16801] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 12/10/2020] [Accepted: 12/10/2020] [Indexed: 12/13/2022]
Abstract
The phosphatidylinositol glycan anchor biosynthesis class S protein (PIGS) gene has recently been implicated in a novel congenital disorder of glycosylation resulting in autosomal recessive inherited glycosylphosphatidylinositol-anchored protein (GPI-AP) deficiency. Previous studies described seven patients with biallelic variants in the PIGS gene, of whom two presented with fetal akinesia and five with global developmental delay and epileptic developmental encephalopathy. We present the molecular and clinical characteristics of six additional individuals from five families with unreported variants in PIGS. All individuals presented with hypotonia, severe global developmental delay, microcephaly, intractable early infantile epilepsy, and structural brain abnormalities. Additional findings include vision impairment, hearing loss, renal malformation, and hypotonic facial appearances with minor dysmorphic features but without a distinctive facial gestalt. Four individuals died due to neurologic complications. GPI anchoring studies performed on one individual revealed a significant decrease in GPI-APs. We confirm that biallelic variants in PIGS cause vitamin pyridoxine-responsive epilepsy due to inherited GPI deficiency and expand the genotype and phenotype of PIGS-related disorder. Further delineation of the molecular spectrum of PIGS-related disorders would improve management, help develop treatments, and encourage the expansion of diagnostic genetic testing to include this gene as a potential cause of neurodevelopmental disorders and epilepsy.
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Affiliation(s)
- Stephanie Efthymiou
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Marina Dutra-Clarke
- Department of Pediatrics, Division of Genetics, University of California, Los Angeles, Los Angeles, CA, USA
| | - Reza Maroofian
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Rauan Kaiyrzhanov
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Marcello Scala
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Giannina Gaslini Institute, Genoa, Italy.,Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | - Javeria Reza Alvi
- Department of Pediatric Neurology, Institute of Child Health, Children's Hospital Lahore, Lahore, Pakistan
| | - Tipu Sultan
- Department of Pediatric Neurology, Institute of Child Health, Children's Hospital Lahore, Lahore, Pakistan
| | - Marilena Christoforou
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Thi Tuyet Mai Nguyen
- Research Center, Saint Justine University Hospital Center, University of Montreal, Montreal, QC, Canada
| | - Kshitij Mankad
- Department of Neuroradiology, Great Ormond Street Hospital for Children, London, UK
| | - Barbara Vona
- Department of Otolaryngology-Head and Neck Surgery, Tübingen Hearing Research Center, Eberhard Karls University, Tübingen, Germany
| | - Aboulfazl Rad
- Department of Otolaryngology-Head and Neck Surgery, Tübingen Hearing Research Center, Eberhard Karls University, Tübingen, Germany
| | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Giannina Gaslini Institute, Genoa, Italy.,Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | - Vincenzo Salpietro
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Giannina Gaslini Institute, Genoa, Italy.,Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | | | - Maha S Zaki
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Center, Cairo, Egypt
| | - Joseph G Gleeson
- Department of Neuroscience, Rady Children's Institute for Genomic Medicine, Howard Hughes Medical Institute, University of California, San Diego, San Diego, CA, USA
| | - Philippe M Campeau
- Research Center, Saint Justine University Hospital Center, University of Montreal, Montreal, QC, Canada
| | - Bianca E Russell
- Department of Pediatrics, Division of Genetics, University of California, Los Angeles, Los Angeles, CA, USA
| | - Henry Houlden
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, University College London, London, UK
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6
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Hussein NH, Amin NS, El Tayebi HM. GPI-AP: Unraveling a New Class of Malignancy Mediators and Potential Immunotherapy Targets. Front Oncol 2020; 10:537311. [PMID: 33344222 PMCID: PMC7746843 DOI: 10.3389/fonc.2020.537311] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 10/19/2020] [Indexed: 12/22/2022] Open
Abstract
With millions of cases diagnosed annually and high economic burden to cover expensive costs, cancer is one of the most difficult diseases to treat due to late diagnosis and severe adverse effects from conventional therapy. This creates an urgent need to find new targets for early diagnosis and therapy. Progress in research revealed the key steps of carcinogenesis. They are called cancer hallmarks. Zooming in, cancer hallmarks are characterized by ligands binding to their cognate receptor and so triggering signaling cascade within cell to make response for stimulus. Accordingly, understanding membrane topology is vital. In this review, we shall discuss one type of transmembrane proteins: Glycosylphosphatidylinositol-Anchored Proteins (GPI-APs), with specific emphasis on those involved in tumor cells by evading immune surveillance and future applications for diagnosis and immune targeted therapy.
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