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Thompson MD, Knaus A. Rare Genetic Developmental Disabilities: Mabry Syndrome (MIM 239300) Index Cases and Glycophosphatidylinositol (GPI) Disorders. Genes (Basel) 2024; 15:619. [PMID: 38790248 PMCID: PMC11121671 DOI: 10.3390/genes15050619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/08/2024] [Accepted: 04/09/2024] [Indexed: 05/26/2024] Open
Abstract
The case report by Mabry et al. (1970) of a family with four children with elevated tissue non-specific alkaline phosphatase, seizures and profound developmental disability, became the basis for phenotyping children with the features that became known as Mabry syndrome. Aside from improvements in the services available to patients and families, however, the diagnosis and treatment of this, and many other developmental disabilities, did not change significantly until the advent of massively parallel sequencing. As more patients with features of the Mabry syndrome were identified, exome and genome sequencing were used to identify the glycophosphatidylinositol (GPI) biosynthesis disorders (GPIBDs) as a group of congenital disorders of glycosylation (CDG). Biallelic variants of the phosphatidylinositol glycan (PIG) biosynthesis, type V (PIGV) gene identified in Mabry syndrome became evidence of the first in a phenotypic series that is numbered HPMRS1-6 in the order of discovery. HPMRS1 [MIM: 239300] is the phenotype resulting from inheritance of biallelic PIGV variants. Similarly, HPMRS2 (MIM 614749), HPMRS5 (MIM 616025) and HPMRS6 (MIM 616809) result from disruption of the PIGO, PIGW and PIGY genes expressed in the endoplasmic reticulum. By contrast, HPMRS3 (MIM 614207) and HPMRS4 (MIM 615716) result from disruption of post attachment to proteins PGAP2 (HPMRS3) and PGAP3 (HPMRS4). The GPI biosynthesis disorders (GPIBDs) are currently numbered GPIBD1-21. Working with Dr. Mabry, in 2020, we were able to use improved laboratory diagnostics to complete the molecular diagnosis of patients he had originally described in 1970. We identified biallelic variants of the PGAP2 gene in the first reported HPMRS patients. We discuss the longevity of the Mabry syndrome index patients in the context of the utility of pyridoxine treatment of seizures and evidence for putative glycolipid storage in patients with HPMRS3. From the perspective of the laboratory innovations made that enabled the identification of the HPMRS phenotype in Dr. Mabry's patients, the need for treatment innovations that will benefit patients and families affected by developmental disabilities is clear.
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Affiliation(s)
- Miles D. Thompson
- Krembil Brain Institute, Toronto Western Hospital, 399 Bathurst Street, Toronto, ON M5T 2S8, Canada
| | - Alexej Knaus
- Institute for Genomic Statistics and Bioinformatics, University Hospital Bonn, University of Bonn, 53127 Bonn, Germany;
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Saracino A, Totaro M, Politano D, DE Giorgis V, Gana S, Papalia G, Pichiecchio A, Plumari M, Rognone E, Varesio C, Orcesi S. PGAP2-Related Hyperphosphatasia-Mental Retardation Syndrome: Report of a Novel Patient, Toward a Broadening of Phenotypic Spectrum and Therapeutic Perspectives. Neuropediatrics 2024; 55:129-134. [PMID: 38365198 DOI: 10.1055/s-0044-1779613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/18/2024]
Abstract
PGAP2 gene has been known to be the cause of "hyperphosphatasia, mental retardation syndrome-3" (HPMRS3). To date, 14 pathogenic variants in PGAP2 have been identified as the cause of this syndrome in 24 patients described in single-case reports or small clinical series with pan-ethnic distribution. We aim to present a pediatric PGAP2-mutated case, intending to further expand the clinical phenotype of the syndrome and to report our experience on a therapeutic approach to drug-resistant epilepsy.We present the clinical, neuroradiological, and genetic characterization of a Caucasian pediatric subject with biallelic pathogenic variants in the PGAP2 gene revealed by next generation sequencing analysis.We identified a subject who presented with global developmental delay and visual impairment. Brain magnetic resonance imaging showed mild hypoplasia of the inferior cerebellar vermis and corpus callosum and mild white matter reduction. Laboratory investigations detected an increase in alkaline phosphatase. At the age of 13 months, he began to present epileptic focal seizures with impaired awareness, which did not respond to various antiseizure medications. Electroencephalogram (EEG) showed progressive background activity disorganization and multifocal epileptic abnormalities. Treatment with high-dose pyridoxine showed partial benefit, but the persistence of seizures and the lack of EEG amelioration prompted us to introduce ketogenic diet treatment.Our case provides a further phenotypical expansion of HPMRS3 to include developmental and epileptic encephalopathy. Due to the limited number of patients reported so far, the full delineation of the clinical spectrum of HPMRS3 and indications for precision medicine would benefit from the description of new cases and their follow-up evaluations.
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Affiliation(s)
- Annalisa Saracino
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
- Department of Child Neurology and Psychiatry, IRCCS Mondino Foundation, Member of ERN-Epicare, Pavia, Italy
| | - Martina Totaro
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
- Department of Child Neurology and Psychiatry, IRCCS Mondino Foundation, Member of ERN-Epicare, Pavia, Italy
| | - Davide Politano
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
- Department of Child Neurology and Psychiatry, IRCCS Mondino Foundation, Member of ERN-Epicare, Pavia, Italy
| | - Valentina DE Giorgis
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
- Department of Child Neurology and Psychiatry, IRCCS Mondino Foundation, Member of ERN-Epicare, Pavia, Italy
| | - Simone Gana
- Neurogenetics Research Center, IRCCS Mondino Foundation, Pavia, Italy
| | - Grazia Papalia
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
- Department of Child Neurology and Psychiatry, IRCCS Mondino Foundation, Member of ERN-Epicare, Pavia, Italy
| | - Anna Pichiecchio
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
- Neuroradiology Department, Advanced Imaging and Radiomics Center, IRCCS Mondino Foundation, Pavia, Italy
| | - Massimo Plumari
- Neurogenetics Research Center, IRCCS Mondino Foundation, Pavia, Italy
| | - Elisa Rognone
- Neuroradiology Department, Advanced Imaging and Radiomics Center, IRCCS Mondino Foundation, Pavia, Italy
| | - Costanza Varesio
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
- Department of Child Neurology and Psychiatry, IRCCS Mondino Foundation, Member of ERN-Epicare, Pavia, Italy
| | - Simona Orcesi
- Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
- Department of Child Neurology and Psychiatry, IRCCS Mondino Foundation, Member of ERN-Epicare, Pavia, Italy
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Murakami Y, Umeshita S, Imanishi K, Yoshioka Y, Ninomiya A, Sunabori T, Likhite S, Koike M, Meyer KC, Kinoshita T. AAV-based gene therapy ameliorated CNS-specific GPI defect in mouse models. Mol Ther Methods Clin Dev 2024; 32:101176. [PMID: 38225934 PMCID: PMC10788267 DOI: 10.1016/j.omtm.2023.101176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 12/11/2023] [Indexed: 01/17/2024]
Abstract
Thirty genes are involved in the biosynthesis and modification of glycosylphosphatidylinositol (GPI)-anchored proteins, and defects in these genes cause inherited GPI deficiency (IGD). PIGA is X-linked and involved in the first step of GPI biosynthesis, and only males are affected by variations in this gene. The main symptoms of IGD are neurological abnormalities, such as developmental delay and seizures. There is no effective treatment at present. We crossed Nestin-Cre mice with Piga-floxed mice to generate CNS-specific Piga knockout (KO) mice. Hemizygous KO male mice died by P10 with severely defective growth. Heterozygous Piga KO female mice are mosaic for Piga expression and showed severe defects in growth and myelination and died by P25. Using these mouse models, we evaluated the effect of gene replacement therapy with adeno-associated virus (AAV). It expressed efficacy within 6 days, and the survival of male mice was extended to up to 3 weeks, whereas 40% of female mice survived for approximately 1 year and the growth defect was improved. However, liver cancer developed in all three treated female mice at 1 year of age, which was probably caused by the AAV vector bearing a strong CAG promoter.
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Affiliation(s)
- Yoshiko Murakami
- Laboratory of Immunoglycobiology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Saori Umeshita
- Laboratory of Immunoglycobiology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Kae Imanishi
- Laboratory of Immunoglycobiology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Yoshichika Yoshioka
- Graduate School of Frontier Bioscience, Osaka University, Suita, Osaka, Japan
- Center for Information and Neural Networks, National Institute of Information and Communications Technology (NICT), Osaka University, Suita, Osaka, Japan
- Center for Quantum Information and Quantum Biology, Osaka University, Suita, Osaka, Japan
| | - Akinori Ninomiya
- Central Instrumentation Laboratory, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
| | - Takehiko Sunabori
- Department of Cell Biology and Neuroscience, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Shibi Likhite
- Center for Gene Therapy, Abigail Wexner Research Institute, Nationwide Children’s Hospital, Columbus, OH, USA
| | - Masato Koike
- Department of Cell Biology and Neuroscience, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Kathrin C. Meyer
- Center for Gene Therapy, Abigail Wexner Research Institute, Nationwide Children’s Hospital, Columbus, OH, USA
- Department of Pediatrics, The Ohio State University, Columbus, OH, USA
| | - Taroh Kinoshita
- Laboratory of Immunoglycobiology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan
- Center for Infectious Disease Education and Research, Osaka University, Suita, Osaka, Japan
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Altassan R, Allers MM, De Graef D, Shah R, de Vries M, Larson A, Glamuzina E, Morava E. Defining the phenotype of PGAP3-congenital disorder of glycosylation; a review of 65 cases. Mol Genet Metab 2023; 140:107688. [PMID: 37647829 PMCID: PMC10872732 DOI: 10.1016/j.ymgme.2023.107688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 08/22/2023] [Accepted: 08/22/2023] [Indexed: 09/01/2023]
Abstract
Biallelic pathogenic variants in PGAP3 cause a rare glycosylphosphatidyl-inositol biogenesis disorder, PGAP3-CDG. This multisystem condition presents with a predominantly neurological phenotype, including developmental delay, intellectual disability, seizures, and hyperphosphatemia. Here, we summarized the phenotype of sixty-five individuals including six unreported individuals from our CDG natural history study with a confirmed PGAP3-CDG diagnosis. Common additional features found in this disorder included brain malformations, behavioral abnormalities, cleft palate, and characteristic facial features. This report aims to review the genetic and metabolic findings and characterize the disease's phenotype while highlighting the necessary clinical approach to improve the management of this rare CDG.
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Affiliation(s)
- Ruqaiah Altassan
- Department of Medical Genomics, Centre for Genomics Medicine, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia; Department of Clinical Genomics, Mayo Clinic, Rochester, MN, United States; College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Michael M Allers
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, United States
| | - Diederik De Graef
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, United States
| | - Rameen Shah
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, United States; Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Maaike de Vries
- Department of Pediatrics, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Austin Larson
- Department of Pediatrics, Section of Genetics, University of Colorado School of Medicine, Aurora, CO, United States
| | - Emma Glamuzina
- Adult and Paediatric National Metabolic Service, Auckland City Hospital, Auckland, New Zealand
| | - Eva Morava
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, United States; Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States; Department of Medical Genetics, University of Pecs Medical School, Pecs, Hungary.
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