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Torres-Valdetano Á, Vallejo-Ruiz V, Milflores-Flores L, Martínez-Morales P. Role of PIGM and PIGX in glycosylphosphatidylinositol biosynthesis and human health (Review). Biomed Rep 2024; 20:57. [PMID: 38414627 PMCID: PMC10895387 DOI: 10.3892/br.2024.1746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 01/09/2024] [Indexed: 02/29/2024] Open
Abstract
Glycosylphosphatidylinositol-glycan (GPI) is an anchor to specific cell surface proteins known as GPI-anchored proteins (APs) that are localized in lipid rafts and may act as cell co-receptors, enzymes and adhesion molecules. The present review investigated the significance of GPI biosynthesis class phosphatidylinositol-glycan (PIG)M and PIGX in GPI synthesis and their implications in human health conditions. PIGM encodes GPI-mannosyltransferase I (MT-I) enzyme that adds the first mannose to the GPI core structure. PIGX encodes the regulatory subunit of GPI-MT-I. The present review summarizes characteristics of the coding sequences of PIGM and PIGX, and their expression in humans, as well as the relevance of GPI-MT-I and the regulatory subunit in maintaining the presence of GPI-APs on the cell surface and their secretion. In addition, the association of PIGM mutations with paroxysmal nocturnal hemoglobinuria and certain types of GPI-deficiency disease and the altered expression of PIGM and PIGX in cancer were also reviewed. In addition, their interaction with other proteins was described, suggesting a complex role in cell biology. PIGM and PIGX are critical genes for GPI synthesis. Understanding gene and protein regulation may provide valuable insights into the role of GPI-APs in cellular processes.
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Affiliation(s)
- Ángeles Torres-Valdetano
- Faculty of Biological Science, Building BIO 1 University City, Autonomous University of Puebla, Puebla 72570, Mexico
| | - Verónica Vallejo-Ruiz
- Mexican Social Security Institute, East Biomedical Research Center, Puebla 74360, Mexico
| | - Lorena Milflores-Flores
- Faculty of Biological Science, Building BIO 1 University City, Autonomous University of Puebla, Puebla 72570, Mexico
| | - Patricia Martínez-Morales
- National Council of Humanities, Sciences and Technologies, East Biomedical Research Center, Puebla 74360, Mexico
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2
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Hutny M, Lipinski P, Jezela-Stanek A. Characteristics of Neuroimaging and Behavioural Phenotype in Polish Patients with PIGV-CDG-An Observational Study and Literature Review. Genes (Basel) 2023; 14:1208. [PMID: 37372388 DOI: 10.3390/genes14061208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 05/28/2023] [Accepted: 05/29/2023] [Indexed: 06/29/2023] Open
Abstract
Congenital disorders of glycosylation (CDGs) are a wide group of genetic diseases characterised by a severe clinical spectrum, consisting of developmental delays, dysmorphisms, and neurological deficits. Mutations in the PIGV gene lead to a disorder called hyperphosphatasia with impaired intellectual development syndrome 1 (HPMRS1), distinct from other CDGs in terms of hyperphosphatemia related to abnormal ALP activity and brachytelephalangy. This article discusses the phenotype of six Polish patients with HPMRS1 with a special focus on behavioural and imaging features, which were not addressed in 26 previously reported cases. The medical records of six patients aged 6 to 22 years were collected and analysed. In all cases, the same PIGV homozygotic mutation (c.1022C>A; p.Ala341Glu) was found, although the patients presented a diverse spectrum of neurological and developmental disorders, concerning in most cases the muscular tonus and general developmental delay. The most prevalent dysmorphic features included hypertelorism, high palate, and finger anomalies, whereas other characteristics present in all previously described cases, such as a short, broad nose and brachytelephalangy, were less frequently observed. Similarly to previous reports, the magnetic resonance (MR) and computed tomography (CT) head scans returned varied results, including physiological and pathological brain images in equal measure, the latter of which consisted of cortical atrophy, delayed myelination, hydrocephalus, and hypoplastic corpus callosum. Each patient exhibited symptoms characteristic of autism spectrum disorders, especially in terms of attention deficits, as well as controlling and expressing emotions. The most common type of sensory processing disorder was over-responsivity. Despite the low prevalence of HPMRS1, the patients reported in the literature presented a rather uniform phenotype, which does not correspond with the one found in each individual of the studied group. Behavioural disorders and sensory impairment require additional care and awareness considering the global developmental delay often observed in these patients.
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Affiliation(s)
- Michal Hutny
- Students' Scientific Society, Department of Paediatric Neurology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, 40-752 Katowice, Poland
| | - Patryk Lipinski
- Department of Pediatrics, Nutrition and Metabolic Diseases, The Children's Memorial Health Institute, 04-730 Warsaw, Poland
| | - Aleksandra Jezela-Stanek
- Department of Genetics and Clinical Immunology, National Institute of Tuberculosis and Lung Diseases, 01-138 Warsaw, Poland
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3
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Messina M, Manea E, Cullup T, Tuschl K, Batzios S. Hyperphosphatasia with mental retardation syndrome 3: Cerebrospinal fluid abnormalities and correction with pyridoxine and Folinic acid. JIMD Rep 2023; 64:42-52. [PMID: 36636587 PMCID: PMC9830023 DOI: 10.1002/jmd2.12347] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 09/16/2022] [Accepted: 10/25/2022] [Indexed: 11/24/2022] Open
Abstract
Glycosylphosphatidylinositol anchored proteins (GPI-APs) represent a class of molecules attached to the external leaflet of the plasma membrane by the GPI anchor where they play important roles in numerous cellular processes including neurogenesis, cell adhesion, immune response and signalling. Within the group of GPI anchor defects, six present with the clinical phenotype of Hyperphosphatasia with Mental Retardation Syndrome (HPMRS, Mabry Syndrome) characterized by moderate to severe intellectual disability, dysmorphic features, hypotonia, seizures and persistent hyperphosphatasia. We report the case of a 5-year-old female with global developmental delay associated with precocious puberty and persistently raised plasma alkaline phosphatase. Targeted next generation sequencing analysis of the HPMRS genes identified novel compound heterozygous variants in the PGAP2 gene (c.103del p.(Leu35Serfs*90)and c.134A > Gp.(His45Arg)) consistent with the diagnosis of HPMRS type 3. Cerebrospinal fluid (CSF) neurotransmitter analysis showed low levels of pyridoxal phosphate and 5-methyltetrahydrofolate and raised homovanillic acid. Supplementation with pyridoxine and folinic acid led to normalization of biochemical abnormalities. The patient continues to make developmental progress with significant improvement in speech and fine motor skills. Our reported case expands the clinical spectrum of HPMRS3 in which multisystem involvement is being increasingly recognized. Furthermore, it shows that miss-targeting GPI-APs and the effect on normal cellular function could provide a physiopathologic explanation for the CSF biochemical abnormalities with management implications for a group of disorders that currently has no treatment that can lead possibly to improved clinical outcomes.
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Affiliation(s)
- Martina Messina
- Metabolic Medicine DepartmentGreat Ormond Street Hospital for ChildrenLondonUK
| | - Emanuela Manea
- Metabolic Medicine DepartmentGreat Ormond Street Hospital for ChildrenLondonUK
| | - Thomas Cullup
- North Thames Genomic Laboratory HubGreat Ormond Street Hospital for ChildrenLondonUK
| | - Karin Tuschl
- Metabolic Medicine DepartmentGreat Ormond Street Hospital for ChildrenLondonUK
- University College London Great Ormond Street Institute for ChildrenLondonUK
| | - Spyros Batzios
- Metabolic Medicine DepartmentGreat Ormond Street Hospital for ChildrenLondonUK
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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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Winter-Paquette LM, Al Suwaidi HH, Sajjad Y, Bricker L. Congenital diaphragmatic hernia and early lethality in PIGL-related disorder. Eur J Med Genet 2022; 65:104501. [DOI: 10.1016/j.ejmg.2022.104501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 02/15/2022] [Accepted: 03/29/2022] [Indexed: 11/03/2022]
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6
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Lipiński P, Stępień KM, Ciara E, Tylki-Szymańska A, Jezela-Stanek A. Skeletal and Bone Mineral Density Features, Genetic Profile in Congenital Disorders of Glycosylation: Review. Diagnostics (Basel) 2021; 11:diagnostics11081438. [PMID: 34441372 PMCID: PMC8391432 DOI: 10.3390/diagnostics11081438] [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: 07/13/2021] [Revised: 08/04/2021] [Accepted: 08/04/2021] [Indexed: 11/25/2022] Open
Abstract
Congenital disorders of glycosylation (CDGs) are a heterogeneous group of disorders with impaired glycosylation of proteins and lipids. These conditions have multisystemic clinical manifestations, resulting in gradually progressive complications including skeletal involvement and reduced bone mineral density. Contrary to PMM2-CDG, all remaining CDG, including ALG12-CDG, ALG3-CDG, ALG9-CDG, ALG6-CDG, PGM3-CDG, CSGALNACT1-CDG, SLC35D1-CDG and TMEM-165, are characterized by well-defined skeletal dysplasia. In some of them, prenatal-onset severe skeletal dysplasia is observed associated with early death. Osteoporosis or osteopenia are frequently observed in all CDG types and are more pronounced in adults. Hormonal dysfunction, limited mobility and inadequate diet are common risk factors for reduced bone mineral density. Skeletal involvement in CDGs is underestimated and, thus, should always be carefully investigated and managed to prevent fractures and chronic pain. With the advent of new therapeutic developments for CDGs, the severity of skeletal complications may be reduced. This review focuses on possible mechanisms of skeletal manifestations, risk factors for osteoporosis, and bone markers in reported paediatric and adult CDG patients.
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Affiliation(s)
- Patryk Lipiński
- Department of Pediatrics, Nutrition and Metabolic Diseases, The Children’s Memorial Health Institute, 04-730 Warsaw, Poland;
- Correspondence:
| | - Karolina M. Stępień
- Adult Inherited Metabolic Diseases, Salford Royal NHS Foundation Trust, Salford M6 8HD, UK;
| | - Elżbieta Ciara
- Department of Medical Genetics, The Children’s Memorial Health Institute, 04-730 Warsaw, Poland;
| | - Anna Tylki-Szymańska
- Department of Pediatrics, Nutrition and Metabolic Diseases, The Children’s Memorial Health Institute, 04-730 Warsaw, Poland;
| | - Aleksandra Jezela-Stanek
- Department of Genetics and Clinical Immunology, National Institute of Tuberculosis and Lung Diseases, 01-138 Warsaw, Poland;
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7
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A CRISPR-Cas9-engineered mouse model for GPI-anchor deficiency mirrors human phenotypes and exhibits hippocampal synaptic dysfunctions. Proc Natl Acad Sci U S A 2021; 118:2014481118. [PMID: 33402532 PMCID: PMC7812744 DOI: 10.1073/pnas.2014481118] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Inherited GPI-anchor biosynthesis deficiencies (IGDs) explain many cases of syndromic intellectual disability. Although diagnostic methods are improving, the pathophysiology underlying the disease remains unclear. Furthermore, we lack rodent models suitable for characterizing cognitive and social disabilities. To address this issue, we generated a viable mouse model for an IGD that mirrors the condition in human patients with a behavioral phenotype and susceptibility to epilepsy. Using this model, we obtained neurological insights such as deficits in synaptic transmission that will facilitate understanding of the pathophysiology of IGDs. Pathogenic germline mutations in PIGV lead to glycosylphosphatidylinositol biosynthesis deficiency (GPIBD). Individuals with pathogenic biallelic mutations in genes of the glycosylphosphatidylinositol (GPI)-anchor pathway exhibit cognitive impairments, motor delay, and often epilepsy. Thus far, the pathophysiology underlying the disease remains unclear, and suitable rodent models that mirror all symptoms observed in human patients have not been available. Therefore, we used CRISPR-Cas9 to introduce the most prevalent hypomorphic missense mutation in European patients, Pigv:c.1022C > A (p.A341E), at a site that is conserved in mice. Mirroring the human pathology, mutant Pigv341E mice exhibited deficits in motor coordination, cognitive impairments, and alterations in sociability and sleep patterns, as well as increased seizure susceptibility. Furthermore, immunohistochemistry revealed reduced synaptophysin immunoreactivity in Pigv341E mice, and electrophysiology recordings showed decreased hippocampal synaptic transmission that could underlie impaired memory formation. In single-cell RNA sequencing, Pigv341E-hippocampal cells exhibited changes in gene expression, most prominently in a subtype of microglia and subicular neurons. A significant reduction in Abl1 transcript levels in several cell clusters suggested a link to the signaling pathway of GPI-anchored ephrins. We also observed elevated levels of Hdc transcripts, which might affect histamine metabolism with consequences for circadian rhythm. This mouse model will not only open the doors to further investigation into the pathophysiology of GPIBD, but will also deepen our understanding of the role of GPI-anchor–related pathways in brain development.
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8
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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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9
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Lipiński P, Tylki-Szymańska A. Congenital Disorders of Glycosylation: What Clinicians Need to Know? Front Pediatr 2021; 9:715151. [PMID: 34540767 PMCID: PMC8446601 DOI: 10.3389/fped.2021.715151] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 08/10/2021] [Indexed: 12/27/2022] Open
Abstract
Congenital disorders of glycosylation (CDG) are a group of clinically heterogeneous disorders characterized by defects in the synthesis of glycans and their attachment to proteins and lipids. This manuscript aims to provide a classification of the clinical presentation, diagnostic methods, and treatment of CDG based on the literature review and our own experience (referral center in Poland). A diagnostic algorithm for CDG was also proposed. Isoelectric focusing (IEF) of serum transferrin (Tf) is still the method of choice for diagnosing N-glycosylation disorders associated with sialic acid deficiency. Nowadays, high-performance liquid chromatography, capillary zone electrophoresis, and mass spectrometry techniques are used, although they are not routinely available. Since next-generation sequencing became more widely available, an improvement in diagnostics has been observed, with more patients and novel CDG subtypes being reported. Early and accurate diagnosis of CDG is crucial for timely implementation of appropriate therapies and improving clinical outcomes. However, causative treatment is available only for few CDG types.
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Affiliation(s)
- Patryk Lipiński
- Department of Pediatrics, Nutrition and Metabolic Diseases, The Children's Memorial Health Institute, Warsaw, Poland
| | - Anna Tylki-Szymańska
- Department of Pediatrics, Nutrition and Metabolic Diseases, The Children's Memorial Health Institute, Warsaw, Poland
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10
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PGAP3 Associated with Hyperphosphatasia with Mental Retardation Plays a Novel Role in Brain Morphogenesis and Neuronal Wiring at Early Development. Cells 2020; 9:cells9081782. [PMID: 32726939 PMCID: PMC7569840 DOI: 10.3390/cells9081782] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/05/2020] [Accepted: 07/11/2020] [Indexed: 12/30/2022] Open
Abstract
Recessive mutations in Post-GPI attachment to proteins 3 (PGAP3) cause the rare neurological disorder hyperphosphatasia with mental retardation syndrome 4 type (HPMRS4). Here, we report a novel homozygous nonsense mutation in PGAP3 (c.265C>T-p.Gln89*), in a 3-year-old boy with unique novel clinical features. These include decreased intrauterine fetal movements, dysgenesis of the corpus callosum, olfactory bulb agenesis, dysmorphic features, cleft palate, left ear constriction, global developmental delay, and hypotonia. The zebrafish functional modeling of PGAP3 loss resulted in HPMRS4-like features, including structural brain abnormalities, dysmorphic cranial and facial features, hypotonia, and seizure-like behavior. Remarkably, morphants displayed defective neural tube formation during the early stages of nervous system development, affecting brain morphogenesis. The significant aberrant midbrain and hindbrain formation demonstrated by separation of the left and right tectal ventricles, defects in the cerebellar corpus, and caudal hindbrain formation disrupted oligodendrocytes expression leading to shorter motor neurons axons. Assessment of zebrafish neuromuscular responses revealed epileptic-like movements at early development, followed by seizure-like behavior, loss of touch response, and hypotonia, mimicking the clinical phenotype human patients. Altogether, we report a novel pathogenic PGAP3 variant associated with unique phenotypic hallmarks, which may be related to the gene's novel role in brain morphogenesis and neuronal wiring.
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11
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Reynolds K, Zhang S, Sun B, Garland MA, Ji Y, Zhou CJ. Genetics and signaling mechanisms of orofacial clefts. Birth Defects Res 2020; 112:1588-1634. [PMID: 32666711 DOI: 10.1002/bdr2.1754] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 06/11/2020] [Accepted: 06/15/2020] [Indexed: 12/31/2022]
Abstract
Craniofacial development involves several complex tissue movements including several fusion processes to form the frontonasal and maxillary structures, including the upper lip and palate. Each of these movements are controlled by many different factors that are tightly regulated by several integral morphogenetic signaling pathways. Subject to both genetic and environmental influences, interruption at nearly any stage can disrupt lip, nasal, or palate fusion and result in a cleft. Here, we discuss many of the genetic risk factors that may contribute to the presentation of orofacial clefts in patients, and several of the key signaling pathways and underlying cellular mechanisms that control lip and palate formation, as identified primarily through investigating equivalent processes in animal models, are examined.
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Affiliation(s)
- Kurt Reynolds
- Department of Biochemistry and Molecular Medicine, University of California Davis, School of Medicine, Sacramento, California, USA.,Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children-Northern California; University of California Davis, School of Medicine, Sacramento, California, USA.,Biochemistry, Molecular, Cellular, and Developmental Biology (BMCDB) Graduate Group, University of California, Davis, California, USA
| | - Shuwen Zhang
- Department of Biochemistry and Molecular Medicine, University of California Davis, School of Medicine, Sacramento, California, USA.,Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children-Northern California; University of California Davis, School of Medicine, Sacramento, California, USA
| | - Bo Sun
- Department of Biochemistry and Molecular Medicine, University of California Davis, School of Medicine, Sacramento, California, USA.,Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children-Northern California; University of California Davis, School of Medicine, Sacramento, California, USA
| | - Michael A Garland
- Department of Biochemistry and Molecular Medicine, University of California Davis, School of Medicine, Sacramento, California, USA.,Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children-Northern California; University of California Davis, School of Medicine, Sacramento, California, USA
| | - Yu Ji
- Department of Biochemistry and Molecular Medicine, University of California Davis, School of Medicine, Sacramento, California, USA.,Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children-Northern California; University of California Davis, School of Medicine, Sacramento, California, USA.,Biochemistry, Molecular, Cellular, and Developmental Biology (BMCDB) Graduate Group, University of California, Davis, California, USA
| | - Chengji J Zhou
- Department of Biochemistry and Molecular Medicine, University of California Davis, School of Medicine, Sacramento, California, USA.,Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children-Northern California; University of California Davis, School of Medicine, Sacramento, California, USA.,Biochemistry, Molecular, Cellular, and Developmental Biology (BMCDB) Graduate Group, University of California, Davis, California, USA
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12
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Hassel B, Rogne AG, Hope S. Intellectual Disability Associated With Pyridoxine-Responsive Epilepsies: The Need to Protect Cognitive Development. Front Psychiatry 2019; 10:116. [PMID: 30930802 PMCID: PMC6423912 DOI: 10.3389/fpsyt.2019.00116] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 02/15/2019] [Indexed: 01/03/2023] Open
Abstract
Pyridoxine (vitamin B6)-responsive epilepsies are severe forms of epilepsy that manifest as seizures immediately after birth, sometimes in utero, sometimes months, or years after birth. Seizures may be treated efficiently by life-long supplementation with pyridoxine or its biologically active form, pyridoxal phosphate, but even so patients may become intellectually disabled, for which there currently is no effective treatment. The condition may be caused by mutations in several genes (TNSALP, PIGV, PIGL, PIGO, PNPO, PROSC, ALDH7A1, MOCS2, or ALDH4A1). Mutations in ALDH7A1, MOCS2, and ALDH4A1 entail build-up of reactive aldehydes (α-aminoadipic semialdehyde, γ-glutamic semialdehyde) that may react non-enzymatically with macromolecules of brain cells. Such reactions may alter the function of macromolecules, and they may produce "advanced glycation end products" (AGEs). AGEs trigger inflammation in the brain. This understanding points to aldehyde-quenching, anti-AGE, or anti-inflammatory therapies as possible strategies to protect cognitive development and prevent intellectual disability in affected children. Studies on how aldehydes traverse cell membranes and how they affect brain function could further the development of therapies for patients with pyridoxine-responsive epilepsies.
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Affiliation(s)
- Bjørnar Hassel
- Department for Neurohabilitation, Oslo University Hospital and University of Oslo, Oslo, Norway.,Norwegian Defence Research Establishment (FFI), Kjeller, Norway
| | - Ane Gretesdatter Rogne
- Department for Neurohabilitation, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Sigrun Hope
- Department for Neurohabilitation, Oslo University Hospital and University of Oslo, Oslo, Norway
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13
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Balobaid A, Ben-Omran T, Ramzan K, Altassan R, Almureikhi M, Musa S, Al-Hashmi N, Al-Owain M, Al-Zaidan H, Al-Hassnan Z, Imtiaz F, Al-Sayed M. Delineating the phenotypic spectrum of hyperphosphatasia with mental retardation syndrome 4 in 14 patients of Middle-Eastern origin. Am J Med Genet A 2018; 176:2850-2857. [PMID: 30345601 DOI: 10.1002/ajmg.a.40627] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Revised: 08/13/2018] [Accepted: 08/13/2018] [Indexed: 12/31/2022]
Abstract
Hyperphosphatasia with mental retardation syndrome 4 (HPMRS4) is a rare autosomal recessive condition caused by an impairment of glycosylphophatidylinositol biosynthesis. The cardinal features of HPMRS4 include; characteristic facial features, severe intellectual disability and various neurologic abnormalities. We report here detailed clinical, biochemical, and molecular findings of 14 patients clinically suspected to have HPMRS4, from three Middle-Eastern Countries; Saudi Arabia, Qatar, and Oman. All patients in our series presented with the cardinal features pointing to HPMRS4 and with an elevated alkaline phosphatase level. Five patients had megalocornea, which have been reported recently in an Arab patient. Additionally, fracture, bilateral coxa valga, camptodactyly, truncal obesity, and hyperpigmented macules of the upper thigh, each was seen once and was not described before with HPMRS4. Additional clinical and radiological findings are described, supporting the novel clinical and radiological findings recently described in Egyptian patients. The utilization of homozygosity mapping coupled with PGAP3 sequencing and whole exome sequencing facilitated the mutation detection in these patients. These missense mutations include c.320C > T (p.S107 L), c.850C > T (p.H284Y), and c.851A > G (p.H284R) in the PGAP3 gene. We believe that the recurrent mutations identified in our cohort may represent founder mutations in big tribes from a certain geographical region of Saudi Arabia, Qatar, and Oman. Therefore, in case of a clinical suspicion of HPMRS4 in these populations, targeted genetic testing for the identified mutations should be performed first to expedite the genetic diagnosis.
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Affiliation(s)
- Ameera Balobaid
- Department of Medical Genetics, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia.,College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Tawfeg Ben-Omran
- Clinical and Metabolic Genetics, Department of Pediatrics, Hamad Medical Corporation, Qatar
| | - Khushnooda Ramzan
- Department of Genetics, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
| | - Ruqaiah Altassan
- Department of Medical Genetics, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
| | - Mariam Almureikhi
- Clinical and Metabolic Genetics, Department of Pediatrics, Hamad Medical Corporation, Qatar
| | - Sara Musa
- Clinical and Metabolic Genetics, Department of Pediatrics, Hamad Medical Corporation, Qatar
| | | | - Mohammed Al-Owain
- Department of Medical Genetics, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia.,College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Hamad Al-Zaidan
- Department of Medical Genetics, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia.,College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Zuhair Al-Hassnan
- Department of Medical Genetics, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia.,College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Faiqa Imtiaz
- Department of Genetics, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
| | - Moeenaldeen Al-Sayed
- Department of Medical Genetics, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia.,College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
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14
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Nguyen TTM, Murakami Y, Wigby KM, Baratang NV, Rousseau J, St-Denis A, Rosenfeld JA, Laniewski SC, Jones J, Iglesias AD, Jones MC, Masser-Frye D, Scheuerle AE, Perry DL, Taft RJ, Le Deist F, Thompson M, Kinoshita T, Campeau PM. Mutations in PIGS, Encoding a GPI Transamidase, Cause a Neurological Syndrome Ranging from Fetal Akinesia to Epileptic Encephalopathy. Am J Hum Genet 2018; 103:602-611. [PMID: 30269814 DOI: 10.1016/j.ajhg.2018.08.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 08/23/2018] [Indexed: 11/17/2022] Open
Abstract
Inherited GPI deficiencies (IGDs) are a subset of congenital disorders of glycosylation that are increasingly recognized as a result of advances in whole-exome sequencing (WES) and whole-genome sequencing (WGS). IGDs cause a series of overlapping phenotypes consisting of seizures, dysmorphic features, multiple congenital malformations, and severe intellectual disability. We present a study of six individuals from three unrelated families in which WES or WGS identified bi-allelic phosphatidylinositol glycan class S (PIGS) biosynthesis mutations. Phenotypes included severe global developmental delay, seizures (partly responding to pyridoxine), hypotonia, weakness, ataxia, and dysmorphic facial features. Two of them had compound-heterozygous variants c.108G>A (p.Trp36∗) and c.101T>C (p.Leu34Pro), and two siblings of another family were homozygous for a deletion and insertion leading to p.Thr439_Lys451delinsArgLeuLeu. The third family had two fetuses with multiple joint contractures consistent with fetal akinesia. They were compound heterozygous for c.923A>G (p.Glu308Gly) and c.468+1G>C, a splicing mutation. Flow-cytometry analyses demonstrated that the individuals with PIGS mutations show a GPI-AP deficiency profile. Expression of the p.Trp36∗ variant in PIGS-deficient HEK293 cells revealed only partial restoration of cell-surface GPI-APs. In terms of both biochemistry and phenotype, loss of function of PIGS shares features with PIGT deficiency and other IGDs. This study contributes to the understanding of the GPI-AP biosynthesis pathway by describing the consequences of PIGS disruption in humans and extending the family of IGDs.
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Affiliation(s)
- Thi Tuyet Mai Nguyen
- Centre Hospitalier Universitaire Sainte Justine Research Center, University of Montreal, Montreal, QC H3T1C5, Canada
| | - Yoshiko Murakami
- Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Kristen M Wigby
- Department of Pediatrics, University of California, San Diego, San Diego, CA 92093, USA
| | - Nissan V Baratang
- Centre Hospitalier Universitaire Sainte Justine Research Center, University of Montreal, Montreal, QC H3T1C5, Canada
| | - Justine Rousseau
- Centre Hospitalier Universitaire Sainte Justine Research Center, University of Montreal, Montreal, QC H3T1C5, Canada
| | - Anik St-Denis
- Centre Hospitalier Universitaire Sainte Justine Research Center, University of Montreal, Montreal, QC H3T1C5, Canada
| | - Jill A Rosenfeld
- Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | | | - Julie Jones
- Greenwood Genetic Center, Greenwood, SC 29646, USA
| | - Alejandro D Iglesias
- NewYork-Presbyterian Morgan Stanley Children's Hospital, New York, NY 10032, USA
| | - Marilyn C Jones
- Department of Pediatrics, University of California, San Diego, San Diego, CA 92093, USA
| | | | | | | | | | - Françoise Le Deist
- Centre Hospitalier Universitaire Sainte Justine Research Center, University of Montreal, Montreal, QC H3T1C5, Canada
| | - Miles Thompson
- Department of Pediatrics, University of California, San Diego, San Diego, CA 92093, USA
| | - Taroh Kinoshita
- Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Philippe M Campeau
- Centre Hospitalier Universitaire Sainte Justine Research Center, University of Montreal, Montreal, QC H3T1C5, Canada.
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15
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Hyperphosphatasia with mental retardation syndrome type 4 In two siblings-expanding the phenotypic and mutational spectrum. Eur J Med Genet 2018; 62:103535. [PMID: 30217754 DOI: 10.1016/j.ejmg.2018.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 08/31/2018] [Accepted: 09/09/2018] [Indexed: 11/20/2022]
Abstract
Hyperphosphatasia with mental retardation syndrome (HPMRS) (OMIM # 239300), is an autosomal recessive disease with phenotypic variability, ranging from mild nonsyndromic intellectual disability to syndromic form with severe intellectual disability, seizures, elevated alkaline phosphatase, brachytelephalangy and facial dysmorphism, Six subgroups of HPMRS were defined in which pathogenic mutations affect genes involved in either synthesis or remodeling of the anchor proteins. Among these, PGAP3 mutations are associated with HPMRS type 4. We report two siblings with a novel homozygous variant in PGAP3 expanding both the phenotypic findings and the mutational spectrum of HPMRS type 4. Developmental delay, hypotonia, facial dysmorphism were the consistent findings with HPMRS in our patients. Large anterior fontanel size, gum hypertrophy, pes equinovarus, concentric ventricle hypertrophy, frontoparietal atrophy and dysphagia were the findings of our patients that have been reported for the first time in this syndrome. Although there is an extensive list of differential diagnoses in patients with developmental delay and hypotonia, the recognizable pattern of facial features, parental consanguinity and mild to moderate serum ALP elevation should be sufficiently suggestive of HPMRS type 4.
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16
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Altassan R, Fox S, Poulin C, Buhas D. Hyperphosphatasia with mental retardation syndrome, expanded phenotype of PIGL related disorders. Mol Genet Metab Rep 2018; 15:46-49. [PMID: 30023290 PMCID: PMC6047459 DOI: 10.1016/j.ymgmr.2018.01.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 01/26/2018] [Accepted: 01/26/2018] [Indexed: 12/20/2022] Open
Abstract
Hypomorphic mutations in six different genes involved in the glycosylphosphatidylinositol (GPI) biogenesis pathway are linked to Mabry syndrome (hyperphosphatasia with mental retardation syndrome, HPMRS). This report on the third affected family with a HPMRS phenotype caused by mutations in PIGL, confirming the seventh GPI biogenesis gene linked to HPMRS. Two siblings presented with the main features of HPMRS; developmental delay, cognitive impairment, seizure disorder, skeletal deformities, and high alkaline phosphatase. We identified two heterozygous mutations in the PIGL gene (P.Trp20Ter and p.Arg88Cys). PIGL mutations have been linked to another distinctive neuroectodermal disorder: CHIME syndrome. The clinical picture of our patients expands the spectrum of PIGL-related phenotypes.
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Key Words
- ALP, alkaline phosphatase
- CHIME syndrome
- CHIME, ocular colobomas, heart defect, ichthyosis, mental retardation, and abnormal ears or epilepsy
- CSS, Coffin-Siris syndrome
- GPI biogenesis
- GPI, glycosylphosphatidylinositol
- HPMRS, hyperphosphatasia with mental retardation syndrome
- Hyperphosphatasia mental retardation syndrome (HPMRS)
- Mabry syndrome
- PIGL gene
- PIGL, phosphatidylinositol glycan anchor biosynthesis class L
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Affiliation(s)
- Ruqaiah Altassan
- Department of Medical Genetics, Montreal Children's Hospital, McGill University Health Center, Montreal, Quebec, Canada
| | - Stephanie Fox
- Department of Medical Genetics, Montreal Children's Hospital, McGill University Health Center, Montreal, Quebec, Canada
| | - Chantal Poulin
- Department of Pediatric, Division of Neurology, Montreal Children's Hospital, McGill University Health Center, Montreal, Quebec, Canada
| | - Daniela Buhas
- Department of Medical Genetics, Montreal Children's Hospital, McGill University Health Center, Montreal, Quebec, Canada.,Department of Human Genetics, McGill University, Montreal, Quebec, Canada
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17
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Knaus A, Pantel JT, Pendziwiat M, Hajjir N, Zhao M, Hsieh TC, Schubach M, Gurovich Y, Fleischer N, Jäger M, Köhler S, Muhle H, Korff C, Møller RS, Bayat A, Calvas P, Chassaing N, Warren H, Skinner S, Louie R, Evers C, Bohn M, Christen HJ, van den Born M, Obersztyn E, Charzewska A, Endziniene M, Kortüm F, Brown N, Robinson PN, Schelhaas HJ, Weber Y, Helbig I, Mundlos S, Horn D, Krawitz PM. Characterization of glycosylphosphatidylinositol biosynthesis defects by clinical features, flow cytometry, and automated image analysis. Genome Med 2018; 10:3. [PMID: 29310717 PMCID: PMC5759841 DOI: 10.1186/s13073-017-0510-5] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 12/11/2017] [Indexed: 12/17/2022] Open
Abstract
Background Glycosylphosphatidylinositol biosynthesis defects (GPIBDs) cause a group of phenotypically overlapping recessive syndromes with intellectual disability, for which pathogenic mutations have been described in 16 genes of the corresponding molecular pathway. An elevated serum activity of alkaline phosphatase (AP), a GPI-linked enzyme, has been used to assign GPIBDs to the phenotypic series of hyperphosphatasia with mental retardation syndrome (HPMRS) and to distinguish them from another subset of GPIBDs, termed multiple congenital anomalies hypotonia seizures syndrome (MCAHS). However, the increasing number of individuals with a GPIBD shows that hyperphosphatasia is a variable feature that is not ideal for a clinical classification. Methods We studied the discriminatory power of multiple GPI-linked substrates that were assessed by flow cytometry in blood cells and fibroblasts of 39 and 14 individuals with a GPIBD, respectively. On the phenotypic level, we evaluated the frequency of occurrence of clinical symptoms and analyzed the performance of computer-assisted image analysis of the facial gestalt in 91 individuals. Results We found that certain malformations such as Morbus Hirschsprung and diaphragmatic defects are more likely to be associated with particular gene defects (PIGV, PGAP3, PIGN). However, especially at the severe end of the clinical spectrum of HPMRS, there is a high phenotypic overlap with MCAHS. Elevation of AP has also been documented in some of the individuals with MCAHS, namely those with PIGA mutations. Although the impairment of GPI-linked substrates is supposed to play the key role in the pathophysiology of GPIBDs, we could not observe gene-specific profiles for flow cytometric markers or a correlation between their cell surface levels and the severity of the phenotype. In contrast, it was facial recognition software that achieved the highest accuracy in predicting the disease-causing gene in a GPIBD. Conclusions Due to the overlapping clinical spectrum of both HPMRS and MCAHS in the majority of affected individuals, the elevation of AP and the reduced surface levels of GPI-linked markers in both groups, a common classification as GPIBDs is recommended. The effectiveness of computer-assisted gestalt analysis for the correct gene inference in a GPIBD and probably beyond is remarkable and illustrates how the information contained in human faces is pivotal in the delineation of genetic entities. Electronic supplementary material The online version of this article (doi:10.1186/s13073-017-0510-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alexej Knaus
- Institut für Medizinische Genetik und Humangenetik, Charité Universitätsmedizin Berlin, 13353, Berlin, Germany.,Max Planck Institute for Molecular Genetics, 14195, Berlin, Germany.,Berlin-Brandenburg School for Regenerative Therapies, Charité Universitätsmedizin Berlin, 13353, Berlin, Germany.,Institute for Genomic Statistics and Bioinformatics, University Hospital Bonn, Rheinische Friedrich-Wilhelms-Universität Bonn, 53127, Bonn, Germany
| | - Jean Tori Pantel
- Institut für Medizinische Genetik und Humangenetik, Charité Universitätsmedizin Berlin, 13353, Berlin, Germany
| | - Manuela Pendziwiat
- Department of Neuropediatrics, University Medical Center Schleswig Holstein, 24105, Kiel, Germany
| | - Nurulhuda Hajjir
- Institut für Medizinische Genetik und Humangenetik, Charité Universitätsmedizin Berlin, 13353, Berlin, Germany
| | - Max Zhao
- Institut für Medizinische Genetik und Humangenetik, Charité Universitätsmedizin Berlin, 13353, Berlin, Germany
| | - Tzung-Chien Hsieh
- Institut für Medizinische Genetik und Humangenetik, Charité Universitätsmedizin Berlin, 13353, Berlin, Germany.,Institute for Genomic Statistics and Bioinformatics, University Hospital Bonn, Rheinische Friedrich-Wilhelms-Universität Bonn, 53127, Bonn, Germany
| | - Max Schubach
- Institut für Medizinische Genetik und Humangenetik, Charité Universitätsmedizin Berlin, 13353, Berlin, Germany.,Berlin Institute of Health (BIH), 10178, Berlin, Germany
| | | | | | - Marten Jäger
- Institut für Medizinische Genetik und Humangenetik, Charité Universitätsmedizin Berlin, 13353, Berlin, Germany.,Berlin Institute of Health (BIH), 10178, Berlin, Germany
| | - Sebastian Köhler
- Institut für Medizinische Genetik und Humangenetik, Charité Universitätsmedizin Berlin, 13353, Berlin, Germany
| | - Hiltrud Muhle
- Department of Neuropediatrics, University Medical Center Schleswig Holstein, 24105, Kiel, Germany
| | - Christian Korff
- Unité de Neuropédiatrie, Université de Genève, CH-1211, Genève, Switzerland
| | - Rikke S Møller
- Danish Epilepsy Centre, DK-4293, Dianalund, Denmark.,Institute for Regional Health Services Research, University of Southern Denmark, DK-5000, Odense, Denmark
| | - Allan Bayat
- Department of Pediatrics, University Hospital of Hvidovre, 2650, Hvicovre, Denmark
| | - Patrick Calvas
- Service de Génétique Médicale, Hôpital Purpan, CHU, 31059, Toulouse, France
| | - Nicolas Chassaing
- Service de Génétique Médicale, Hôpital Purpan, CHU, 31059, Toulouse, France
| | | | | | | | - Christina Evers
- Genetische Poliklinik, Universitätsklinik Heidelberg, 69120, Heidelberg, Germany
| | - Marc Bohn
- St. Bernward Krankenhaus, 31134, Hildesheim, Germany
| | - Hans-Jürgen Christen
- Kinderkrankenhaus auf der Bult, Hannoversche Kinderheilanstalt, 30173, Hannover, Germany
| | | | - Ewa Obersztyn
- Institute of Mother and Child Department of Molecular Genetics, 01-211, Warsaw, Poland
| | - Agnieszka Charzewska
- Institute of Mother and Child Department of Molecular Genetics, 01-211, Warsaw, Poland
| | - Milda Endziniene
- Neurology Department, Lithuanian University of Health Sciences, 50009, Kaunas, Lithuania
| | - Fanny Kortüm
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Natasha Brown
- Victorian Clinical Genetics Services, Royal Children's Hospital, MCRI, Parkville, Australia.,Department of Clinical Genetics, Austin Health, Heidelberg, Australia
| | - Peter N Robinson
- The Jackson Laboratory for Genomic Medicine, 06032, Farmington, USA
| | - Helenius J Schelhaas
- Departement of Neurology, Academic Center for Epileptology, 5590, Heeze, The Netherlands
| | - Yvonne Weber
- Department of Neurology and Epileptology and Hertie Institute for Clinical Brain Research, University Tübingen, 72076, Tübingen, Germany
| | - Ingo Helbig
- Institute for Genomic Statistics and Bioinformatics, University Hospital Bonn, Rheinische Friedrich-Wilhelms-Universität Bonn, 53127, Bonn, Germany.,Pediatric Neurology, Children's Hospital of Philadelphia, 3401, Philadelphia, USA
| | - Stefan Mundlos
- Institut für Medizinische Genetik und Humangenetik, Charité Universitätsmedizin Berlin, 13353, Berlin, Germany.,Max Planck Institute for Molecular Genetics, 14195, Berlin, Germany
| | - Denise Horn
- Institut für Medizinische Genetik und Humangenetik, Charité Universitätsmedizin Berlin, 13353, Berlin, Germany.
| | - Peter M Krawitz
- Institut für Medizinische Genetik und Humangenetik, Charité Universitätsmedizin Berlin, 13353, Berlin, Germany. .,Max Planck Institute for Molecular Genetics, 14195, Berlin, Germany. .,Institute for Genomic Statistics and Bioinformatics, University Hospital Bonn, Rheinische Friedrich-Wilhelms-Universität Bonn, 53127, Bonn, Germany.
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18
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Liu YS, Guo XY, Hirata T, Rong Y, Motooka D, Kitajima T, Murakami Y, Gao XD, Nakamura S, Kinoshita T, Fujita M. N-Glycan-dependent protein folding and endoplasmic reticulum retention regulate GPI-anchor processing. J Cell Biol 2017; 217:585-599. [PMID: 29255114 PMCID: PMC5800811 DOI: 10.1083/jcb.201706135] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 10/23/2017] [Accepted: 11/16/2017] [Indexed: 12/14/2022] Open
Abstract
N-Glycosylation and GPI anchoring of proteins occur in the endoplasmic reticulum (ER). Liu et al. revealed N-glycans participate in quality control and temporal ER retention of GPI-anchored proteins (GPI-APs), ensuring their correct folding and GPI processing before exiting from the ER. Chronic ER stress induced exposure of unprocessed GPI-APs on the cell surface. Glycosylphosphatidylinositol (GPI) anchoring of proteins is a conserved posttranslational modification in the endoplasmic reticulum (ER). Soon after GPI is attached, an acyl chain on the GPI inositol is removed by post-GPI attachment to proteins 1 (PGAP1), a GPI-inositol deacylase. This is crucial for switching GPI-anchored proteins (GPI-APs) from protein folding to transport states. We performed haploid genetic screens to identify factors regulating GPI-inositol deacylation, identifying seven genes. In particular, calnexin cycle impairment caused inefficient GPI-inositol deacylation. Calnexin was specifically associated with GPI-APs, dependent on N-glycan and GPI moieties, and assisted efficient GPI-inositol deacylation by PGAP1. Under chronic ER stress caused by misfolded GPI-APs, inositol-acylated GPI-APs were exposed on the cell surface. These results indicated that N-glycans participate in quality control and temporal ER retention of GPI-APs, ensuring their correct folding and GPI processing before exiting from the ER. Once the system is disrupted by ER stress, unprocessed GPI-APs become exposed on the cell surface.
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Affiliation(s)
- Yi-Shi Liu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Jiangsu, China
| | - Xin-Yu Guo
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Jiangsu, China
| | - Tetsuya Hirata
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.,World Premier International Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Yao Rong
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Jiangsu, China
| | - Daisuke Motooka
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Toshihiko Kitajima
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Jiangsu, China
| | - Yoshiko Murakami
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.,World Premier International Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Jiangsu, China
| | - Shota Nakamura
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Taroh Kinoshita
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan .,World Premier International Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Morihisa Fujita
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Jiangsu, China
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19
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Zehavi Y, von Renesse A, Daniel-Spiegel E, Sapir Y, Zalman L, Chervinsky I, Schuelke M, Straussberg R, Spiegel R. A homozygous PIGO mutation associated with severe infantile epileptic encephalopathy and corpus callosum hypoplasia, but normal alkaline phosphatase levels. Metab Brain Dis 2017; 32:2131-2137. [PMID: 28900819 DOI: 10.1007/s11011-017-0109-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Accepted: 09/06/2017] [Indexed: 01/20/2023]
Abstract
We describe two sisters from a consanguineous Arab family with global developmental delay, dystrophy, axial hypotonia, epileptic encephalopathy dominated by intractable complex partial seizures that were resistant to various anti-epileptic treatments. Dysmorphic features comprised low set ears, hypertelorism, upslanting palpebral fissures, a broad nasal bridge, and blue sclera with elongated eyelashes. Brain MRI in both children showed a corpus callosum hypoplasia that was evident already in utero and evolving cortical atrophy. Autozygosity mapping in combination with Whole Exome Sequencing revealed a homozygous missense mutation in the PIGO gene [c.765G > A, NM_032634.3] that affected a highly conserved methionine in the alkaline phosphatase-like core domain of the protein [p.(Met255Ile), NP_116023.2]. PIGO encodes the GPI-ethanolamine phosphate transferase 3, which is crucial for the final synthetic step of the glycosylphosphatidylinositol-anchor that attaches many enzymes to their cell surfaces, such as the alkaline phosphatase and granulocyte surface markers. Interestingly, measurement of serum alkaline phosphatase activities in both children was normal or only slightly elevated. Quantification of granulocyte surface antigens CD16/24/59 yielded reduced levels only for CD59. Phenotype analysis of our and other published patients with PIGO mutations reveals a more severe affectation and predominantly neurological presentation in individuals carrying a mutation in the alkaline phosphatase-like core domain thereby hinting towards a genotype-phenotype relation for PIGO gene mutations.
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Affiliation(s)
- Yoav Zehavi
- Pediatric Department B, Emek Medical Center, 1834111, Afula, Israel
| | - Anja von Renesse
- NeuroCure Clinical Research Center and Department of Neuropediatrics, Charité Universitätsmedizin, Berlin, Germany
| | - Etty Daniel-Spiegel
- Department of Obstetrics and Gynecology, Ultrasound Unit, Emek Medical Center, Afula, Israel
- Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Yonatan Sapir
- Department of Radiology, Emek Medical Center, Afula, Israel
| | - Luci Zalman
- Hematology-Oncology Service, Emek Medical Center, Afula, Israel
| | | | - Markus Schuelke
- NeuroCure Clinical Research Center and Department of Neuropediatrics, Charité Universitätsmedizin, Berlin, Germany
| | - Rachel Straussberg
- Pediatric Neurology Unit, Schneider Children's Medical Center, Petach Tikva, Israel
| | - Ronen Spiegel
- Pediatric Department B, Emek Medical Center, 1834111, Afula, Israel.
- Rappaport Faculty of Medicine, Technion, Haifa, Israel.
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20
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Mutations in GPAA1, Encoding a GPI Transamidase Complex Protein, Cause Developmental Delay, Epilepsy, Cerebellar Atrophy, and Osteopenia. Am J Hum Genet 2017; 101:856-865. [PMID: 29100095 DOI: 10.1016/j.ajhg.2017.09.020] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 09/21/2017] [Indexed: 11/21/2022] Open
Abstract
Approximately one in every 200 mammalian proteins is anchored to the cell membrane through a glycosylphosphatidylinositol (GPI) anchor. These proteins play important roles notably in neurological development and function. To date, more than 20 genes have been implicated in the biogenesis of GPI-anchored proteins. GPAA1 (glycosylphosphatidylinositol anchor attachment 1) is an essential component of the transamidase complex along with PIGK, PIGS, PIGT, and PIGU (phosphatidylinositol-glycan biosynthesis classes K, S, T, and U, respectively). This complex orchestrates the attachment of the GPI anchor to the C terminus of precursor proteins in the endoplasmic reticulum. Here, we report bi-allelic mutations in GPAA1 in ten individuals from five families. Using whole-exome sequencing, we identified two frameshift mutations (c.981_993del [p.Gln327Hisfs∗102] and c.920delG [p.Gly307Alafs∗11]), one intronic splicing mutation (c.1164+5C>T), and six missense mutations (c.152C>T [p.Ser51Leu], c.160_161delinsAA [p.Ala54Asn], c.527G>C [p.Trp176Ser], c.869T>C [p.Leu290Pro], c.872T>C [p.Leu291Pro], and c.1165G>C [p.Ala389Pro]). Most individuals presented with global developmental delay, hypotonia, early-onset seizures, cerebellar atrophy, and osteopenia. The splicing mutation was found to decrease GPAA1 mRNA. Moreover, flow-cytometry analysis of five available individual samples showed that several GPI-anchored proteins had decreased cell-surface abundance in leukocytes (FLAER, CD16, and CD59) or fibroblasts (CD73 and CD109). Transduction of fibroblasts with a lentivirus encoding the wild-type protein partially rescued the deficiency of GPI-anchored proteins. These findings highlight the role of the transamidase complex in the development and function of the cerebellum and the skeletal system.
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21
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Reynolds KK, Juusola J, Rice GM, Giampietro PF. Prenatal presentation of Mabry syndrome with congenital diaphragmatic hernia and phenotypic overlap with Fryns syndrome. Am J Med Genet A 2017; 173:2776-2781. [PMID: 28817240 DOI: 10.1002/ajmg.a.38379] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 06/28/2017] [Accepted: 07/01/2017] [Indexed: 12/19/2022]
Abstract
We report on a family in which initial features were compatible with Fryns syndrome. The first sibling was a stillborn female with a left diaphragmatic hernia (DH). Her clinical features overlapped with Fryns syndrome. The second pregnancy, a male fetus, was followed for polyhydramnios, hypoplastic mandible, mild enlargement of the fetal bladder, hydronephrosis, and rocker bottom foot deformities. He had facial features similar to his sibling and a large cleft of the secondary palate, small jaw, and secundum atrial septal defect. He underwent surgical repair of imperforate anus, intestinal malrotation, and placement of mucous fistula for biopsy positive Hirschsprung disease. An elevated alkaline phosphatase level of 1569 U/L was reported. Whole exome sequencing performed on the second child demonstrated compound heterozygosity for the PIGV gene with the p.A341E and p.A418D variants in trans. Hyperphosphatasia with mental retardation syndrome (HPMRS) is caused by mutations in PIGV and includes hyperphosphatasia as a diagnostic hallmark. Our patient exhibited hyperphosphatasia but without any storage material in his skin cells. His features remain similar to his sister's, but includes seizures and lacks diaphragmatic hernia. Until now, HPMRS and Fryns syndrome, despite overlapping features, were considered mutually exclusive as HPMRS involves hyperphosphatasia and Fryns typically exhibits DH. Recent identification of PIGN mutations associated with several cases of Fryns syndrome point to a common pathogenetic etiology involving inborn errors of the glycosylphosphatidylinositiol anchor biosynthetic pathway. A diagnosis of HPMRS should be considered when DH is encountered on prenatal ultrasound.
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Abdel-Hamid M, Issa M, Otaify G, Abdel-Ghafar S, Elbendary H, Zaki M. PGAP3
-related hyperphosphatasia with mental retardation syndrome: Report of 10 new patients and a homozygous founder mutation. Clin Genet 2017; 93:84-91. [DOI: 10.1111/cge.13033] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Revised: 03/30/2017] [Accepted: 04/03/2017] [Indexed: 11/27/2022]
Affiliation(s)
- M.S. Abdel-Hamid
- Medical Molecular Genetics Department, Human Genetics and Genome Research Division; National Research Centre; Cairo Egypt
| | - M.Y. Issa
- Clinical Genetics Department, Human Genetics and Genome Research Division; National Research Centre; Cairo Egypt
| | - G.A. Otaify
- Clinical Genetics Department, Human Genetics and Genome Research Division; National Research Centre; Cairo Egypt
| | - S.F. Abdel-Ghafar
- Medical Molecular Genetics Department, Human Genetics and Genome Research Division; National Research Centre; Cairo Egypt
| | - H.M. Elbendary
- Child Health Department, Medical Research Division; National Research Centre; Cairo Egypt
| | - M.S. Zaki
- Clinical Genetics Department, Human Genetics and Genome Research Division; National Research Centre; Cairo Egypt
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23
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Johnstone DL, Nguyen TTM, Murakami Y, Kernohan KD, Tétreault M, Goldsmith C, Doja A, Wagner JD, Huang L, Hartley T, St-Denis A, le Deist F, Majewski J, Bulman DE, Kinoshita T, Dyment DA, Boycott KM, Campeau PM. Compound heterozygous mutations in the gene PIGP are associated with early infantile epileptic encephalopathy. Hum Mol Genet 2017; 26:1706-1715. [DOI: 10.1093/hmg/ddx077] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 02/27/2017] [Indexed: 12/27/2022] Open
Affiliation(s)
- Devon L. Johnstone
- Children’s Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario K1H8L1, Canada
| | - Thi-Tuyet-Mai Nguyen
- Research Center, CHU Sainte-Justine, University of Montreal, Montreal, Quebec H3T1C5, Canada
| | - Yoshiko Murakami
- WPI Immunology Frontier Research Center and Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Kristin D. Kernohan
- Children’s Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario K1H8L1, Canada
| | - Martine Tétreault
- Department of Human Genetics, McGill University, Montreal, Quebec H3A1B1, Canada
- McGill University and Genome Quebec Innovation Centre, Montreal, Quebec H3A0G1, Canada
| | - Claire Goldsmith
- Department of Genetics, Children’s Hospital of Eastern Ontario, Ottawa, Ontario K1H8L1, Canada
| | - Asif Doja
- Division of Neurology, Department of Pediatrics, Children’s Hospital of Eastern Ontario, Ottawa, Ontario K1H8L1, Canada
| | - Justin D. Wagner
- Children’s Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario K1H8L1, Canada
| | - Lijia Huang
- Children’s Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario K1H8L1, Canada
| | - Taila Hartley
- Children’s Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario K1H8L1, Canada
| | - Anik St-Denis
- Research Center, CHU Sainte-Justine, University of Montreal, Montreal, Quebec H3T1C5, Canada
| | - Françoise le Deist
- Research Center, CHU Sainte-Justine, University of Montreal, Montreal, Quebec H3T1C5, Canada
| | - Jacek Majewski
- Department of Human Genetics, McGill University, Montreal, Quebec H3A1B1, Canada
- McGill University and Genome Quebec Innovation Centre, Montreal, Quebec H3A0G1, Canada
| | - Dennis E. Bulman
- Children’s Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario K1H8L1, Canada
| | - Taroh Kinoshita
- WPI Immunology Frontier Research Center and Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - David A. Dyment
- Children’s Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario K1H8L1, Canada
- Department of Genetics, Children’s Hospital of Eastern Ontario, Ottawa, Ontario K1H8L1, Canada
| | - Kym M. Boycott
- Children’s Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario K1H8L1, Canada
- Department of Genetics, Children’s Hospital of Eastern Ontario, Ottawa, Ontario K1H8L1, Canada
| | - Philippe M. Campeau
- Research Center, CHU Sainte-Justine, University of Montreal, Montreal, Quebec H3T1C5, Canada
- Department of Pediatrics, Sainte-Justine Hospital, University of Montreal, Montreal, Quebec H3T1C5, Canada
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24
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Xue J, Li H, Zhang Y, Yang Z. Clinical and genetic analysis of two Chinese infants with Mabry syndrome. Brain Dev 2016; 38:807-18. [PMID: 27177984 DOI: 10.1016/j.braindev.2016.04.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Revised: 04/05/2016] [Accepted: 04/12/2016] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Hyperphosphatasia mental retardation syndrome (Mabry syndrome) is an autosomal recessive disorder. We aim to analyze two Chinese patients diagnosed as Mabry syndrome. METHODS The clinical manifestations, diagnosis and treatment were observed in two patients. Genetic analysis including PIGV and PIGO was examined. RESULTS Two patients were diagnosed as Mabry syndrome clinically and genetically. Developmental delay, hyperphosphatasia and seizures were presented in both of them. Typical facial dysmorphism and hypoplastic terminal phalanges were only found in one. Some novel presentations including congenital laryngeal cartilage softening, inguinal hernia, broken palmprint, optic atrophy and skeleton dysplasia such as carpal age delay and metaphysis anomalies were observed in two patients. Molecular genetic analysis revealed compound heterozygous mutations of PIGV or PIGO in our patients, including c.615C>G (p.Asn205Lys) and c.854A>G (p.Tyr285Cys) of PIGV in patient 1, and c.458T>C (p.Phe153Ser) and c.1355_1356del (p.Ala452Glyfs*52) of PIGO in patient 2. Additionally, a heterozygous c.2926G>A (Asp976Asn) of PCDH19 was identified in patient with PIGV mutations, the causative gene of Epilepsy and mental retardation limited to females (EFMR). CONCLUSION To our best knowledge, this is the first time to report Chinese patients diagnosed as Mabry syndrome. For the PCDH19 mutation in our patient carrying PIGV mutations, due to lacking characteristics of EFMR and the ambiguity results in pathogenicity analysis, we were not sure how much pathogenic role PCDH19 mutation shared with PIGV mutations in this disease. The novel mutations of PIGV and PIGO, and novel clinical manifestations reported here might expand the genotype and phenotype spectrum of Mabry syndrome.
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Affiliation(s)
- Jiao Xue
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Hui Li
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yuehua Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Zhixian Yang
- Department of Pediatrics, Peking University First Hospital, Beijing, China.
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25
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Knaus A, Awaya T, Helbig I, Afawi Z, Pendziwiat M, Abu-Rachma J, Thompson MD, Cole DE, Skinner S, Annese F, Canham N, Schweiger MR, Robinson PN, Mundlos S, Kinoshita T, Munnich A, Murakami Y, Horn D, Krawitz PM. Rare Noncoding Mutations Extend the Mutational Spectrum in the PGAP3 Subtype of Hyperphosphatasia with Mental Retardation Syndrome. Hum Mutat 2016; 37:737-44. [PMID: 27120253 PMCID: PMC5084765 DOI: 10.1002/humu.23006] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 04/03/2016] [Indexed: 01/27/2023]
Abstract
HPMRS or Mabry syndrome is a heterogeneous glycosylphosphatidylinositol (GPI) anchor deficiency that is caused by an impairment of synthesis or maturation of the GPI‐anchor. The expressivity of the clinical features in HPMRS varies from severe syndromic forms with multiple organ malformations to mild nonsyndromic intellectual disability. In about half of the patients with the clinical diagnosis of HPMRS, pathogenic mutations can be identified in the coding region in one of the six genes, one among them is PGAP3. In this work, we describe a screening approach with sequence specific baits for transcripts of genes of the GPI pathway that allows the detection of functionally relevant mutations also including introns and the 5′ and 3′ UTR. By this means, we also identified pathogenic noncoding mutations, which increases the diagnostic yield for HPMRS on the basis of intellectual disability and elevated serum alkaline phosphatase. In eight affected individuals from different ethnicities, we found seven novel pathogenic mutations in PGAP3. Besides five missense mutations, we identified an intronic mutation, c.558‐10G>A, that causes an aberrant splice product and a mutation in the 3′UTR, c.*559C>T, that is associated with substantially lower mRNA levels. We show that our novel screening approach is a useful rapid detection tool for alterations in genes coding for key components of the GPI pathway.
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Affiliation(s)
- Alexej Knaus
- Institute for Medical and Human Genetics, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, Berlin, 13353, Germany.,Max Planck Institute for Molecular Genetics, Ihnestr. 63-73, Berlin, 14195, Germany.,Berlin-Brandenburg School for Regenerative Therapies (BSRT), Charité Campus Virchow Klinikum, Augustenburger Platz 1, Berlin, 13353, Germany
| | - Tomonari Awaya
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Sakyo, Kyoto, 6068507, Japan
| | - Ingo Helbig
- Division of Child Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, 19104-4399.,Department of Neuropediatrics, University Medical Center Schleswig-Holstein, Kiel 24105, Germany
| | - Zaid Afawi
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Manuela Pendziwiat
- Department of Neuropediatrics, University Medical Center Schleswig-Holstein, Kiel 24105, Germany
| | | | - Miles D Thompson
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - David E Cole
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | | | - Fran Annese
- Greenwood Genetic Center, Greenwood, South Carolina
| | - Natalie Canham
- North West Thames Regional Genetics Service, Northwick Park Hospital, Harrow, HA1 3UJ, UK
| | - Michal R Schweiger
- Epigenomics and Tumor Genetics, CCG, University of Cologne, Cologne, 50931, Germany
| | - Peter N Robinson
- Institute for Medical and Human Genetics, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, Berlin, 13353, Germany.,Max Planck Institute for Molecular Genetics, Ihnestr. 63-73, Berlin, 14195, Germany
| | - Stefan Mundlos
- Institute for Medical and Human Genetics, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, Berlin, 13353, Germany.,Max Planck Institute for Molecular Genetics, Ihnestr. 63-73, Berlin, 14195, Germany
| | - Taroh Kinoshita
- Department of Immunoregulation, Research Institute for Microbial Diseases, Osaka University, Osaka, 565, Japan.,World Premier International Immunology Frontier Research Center, Osaka University, Osaka, 565, Japan
| | - Arnold Munnich
- Hôpital Necker - Enfants Malades, Unité INSERM 781, Laboratoire de génétique moléculaire Tour Lavoisier - 2ème étage, Paris Cedex, 15 75743, France
| | - Yoshiko Murakami
- Department of Immunoregulation, Research Institute for Microbial Diseases, Osaka University, Osaka, 565, Japan.,World Premier International Immunology Frontier Research Center, Osaka University, Osaka, 565, Japan
| | - Denise Horn
- Institute for Medical and Human Genetics, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, Berlin, 13353, Germany
| | - Peter M Krawitz
- Institute for Medical and Human Genetics, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, Berlin, 13353, Germany.,Max Planck Institute for Molecular Genetics, Ihnestr. 63-73, Berlin, 14195, Germany
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26
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Congenital disorder of glycosylphosphatidylinositol (GPI)-anchor biosynthesis--The phenotype of two patients with novel mutations in the PIGN and PGAP2 genes. Eur J Paediatr Neurol 2016; 20:462-73. [PMID: 26879448 DOI: 10.1016/j.ejpn.2016.01.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 01/10/2016] [Accepted: 01/11/2016] [Indexed: 12/21/2022]
Abstract
BACKGROUND Glycosylphosphatidylinositol (GPI)-anchor deficiencies are a new subclass of congenital disorders of glycosylation. About 26 genes are involved in the GPI-anchor biosynthesis and remodeling pathway, of which mutations in thirteen have been reported to date as causative of a diverse spectrum of intellectual disabilities. Since the clinical phenotype of these disorders varies and the number of described individuals is limited, we present new patients with inherited GPI-anchor deficiency (IGD) caused by mutations in the PGAP2 and PIGN genes. PATIENTS AND METHODS The first girl presented with profound psychomotor retardation, low birth parameters, and chest deformities already existing in neonatal period. The disease course was slowly progressive with severe hypotonia, chronic fever, and respiration insufficiency at the age of 6. The second girl showed profound psychomotor retardation, marked hypotonia, and high birth weight (97 centile). Dysmorphy was mild or absent in both girls. Whole exome sequencing revealed novel variants in the genes PGAP2 (c.2T>G and c.221G>A) and PIGN (c.790G>A and c.932T>G). Impaired GPI binding were was subsequently uncovered, although the hyperactivity of alkaline phosphatase (a GPI-anchored protein) occurred only in first case. CONCLUSIONS Based on our results we can conclude that: 1. GPI-anchor biosynthesis disorders may represent a relatively frequent and overlooked metabolic defect; 2. The utility of GPI binding assessment as a screening test for this group of rare diseases requires further studies.
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Abstract
Hypophosphatasia (HPP) is due to deficient activity of the tissue-nonspecific isoenzyme of alkaline phosphatase (TNAP). This enzyme cleaves extracellular substrates inorganic pyrophosphates (PPi), pyridoxal-5'-phosphate (PLP), phosphoethanolamine (PEA) and nucleotides, and probably other substrates not yet identified. During the last 15 years the role of TNAP in mineralization, and to a less degree in brain, has been investigated, providing hypotheses and explanations for both bone and neuronal HPP phenotypes. ALPL, the gene encoding TNAP, is subject to many mutations, mostly missense mutations. A few number of mutations are recurrently found and may be quite frequent in particular populations. This reflects founder effects. The great variety of mutations results in a great number of compound heterozygous genotypes and in highly variable clinical expressivity. A good correlation was observed between the severity of the disease and in vitro enzymatic activity of the mutant protein measured after site-directed mutagenesis. Many missense mutations found in severe hypophosphatasia produced a mutant protein that failed to reach the cell membrane , was accumulated in the cis-Golgi and was subsequently degraded in the proteasome. Missense mutations located in the catalytic site or in the homodimer interface were often shown by site-directed mutagenesis to have a dominant negative effect. Currently molecular diagnosis of HPP is based on the sequencing of the coding sequence of ALPL that allows detection of approximately 95 % of mutations in severe cases. In addition, other genes, especially genes encoding proteins involved in the regulation of extracellular PPi concentration, could modify the phenotype (modifier genes).
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28
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Yang L, Gao Z, Hu L, Wu G, Yang X, Zhang L, Zhu Y, Wong BS, Xin W, Sy MS, Li C. Glycosylphosphatidylinositol Anchor Modification Machinery Deficiency Is Responsible for the Formation of Pro-Prion Protein (PrP) in BxPC-3 Protein and Increases Cancer Cell Motility. J Biol Chem 2015; 291:3905-17. [PMID: 26683373 DOI: 10.1074/jbc.m115.705830] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Indexed: 11/06/2022] Open
Abstract
The normal cellular prion protein (PrP) is a glycosylphosphatidylinositol (GPI)-anchored cell surface glycoprotein. However, in pancreatic ductal adenocarcinoma cell lines, such as BxPC-3, PrP exists as a pro-PrP retaining its glycosylphosphatidylinositol (GPI) peptide signaling sequence. Here, we report the identification of another pancreatic ductal adenocarcinoma cell line, AsPC-1, which expresses a mature GPI-anchored PrP. Comparison of the 24 genes involved in the GPI anchor modification pathway between AsPC-1 and BxPC-3 revealed 15 of the 24 genes, including PGAP1 and PIG-F, were down-regulated in the latter cells. We also identified six missense mutations in DPM2, PIG-C, PIG-N, and PIG-P alongside eight silent mutations. When BxPC-3 cells were fused with Chinese hamster ovary (CHO) cells, which lack endogenous PrP, pro-PrP was successfully converted into mature GPI-anchored PrP. Expression of the individual gene, such as PGAP1, PIG-F, or PIG-C, into BxPC-3 cells does not result in phosphoinositide-specific phospholipase C sensitivity of PrP. However, when PIG-F but not PIG-P is expressed in PGAP1-expressing BxPC-3 cells, PrP on the surface of the cells becomes phosphoinositide-specific phospholipase C-sensitive. Thus, low expression of PIG-F and PGAP1 is the major factor contributing to the accumulation of pro-PrP. More importantly, BxPC-3 cells expressing GPI-anchored PrP migrate much slower than BxPC-3 cells bearing pro-PrP. In addition, GPI-anchored PrP-bearing AsPC-1 cells also migrate slower than pro-PrP bearing BxPC-3 cells, although both cells express filamin A. "Knocking out" PRNP in BxPC-3 cell drastically reduces its migration. Collectively, these results show that multiple gene irregularity in BxPC-3 cells is responsible for the formation of pro-PrP, and binding of pro-PrP to filamin A contributes to enhanced tumor cell motility.
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Affiliation(s)
- Liheng Yang
- From the Wuhan Institute of Virology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 44 Xiao Hong Shan Zhong Qu, Wuhan, 430071, China, the Department of Virology, School of Life Sciences, Wuhan University, State Key Laboratory of Virology, Wuhan, 430071, China
| | - Zhenxing Gao
- From the Wuhan Institute of Virology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 44 Xiao Hong Shan Zhong Qu, Wuhan, 430071, China, the Department of Virology, School of Life Sciences, Wuhan University, State Key Laboratory of Virology, Wuhan, 430071, China
| | - Lipeng Hu
- From the Wuhan Institute of Virology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 44 Xiao Hong Shan Zhong Qu, Wuhan, 430071, China
| | - Guiru Wu
- From the Wuhan Institute of Virology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 44 Xiao Hong Shan Zhong Qu, Wuhan, 430071, China
| | - Xiaowen Yang
- the Department of the First Abdominal Surgery, Jiangxi Tumor Hospital, Nanchang 330029, China
| | - Lihua Zhang
- the Department of Pathology, Zhongda Hospital, Southeast University, Nanjing, 210009, China
| | - Ying Zhu
- the Department of Virology, School of Life Sciences, Wuhan University, State Key Laboratory of Virology, Wuhan, 430071, China
| | - Boon-Seng Wong
- the Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Wei Xin
- the Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44102, and
| | - Man-Sun Sy
- the Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44102, and
| | - Chaoyang Li
- the State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Hubei Collaborative Innovation Center for Industrial Fermentation, 44 Xiao Hong Shan Zhong Qu, Wuhan 430071, China
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Khayat M, Tilghman JM, Chervinsky I, Zalman L, Chakravarti A, Shalev SA. A PIGN mutation responsible for multiple congenital anomalies-hypotonia-seizures syndrome 1 (MCAHS1) in an Israeli-Arab family. Am J Med Genet A 2015; 170A:176-82. [PMID: 26364997 DOI: 10.1002/ajmg.a.37375] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 08/27/2015] [Indexed: 12/13/2022]
Abstract
Mutations in the PIGN gene involved in the glycosylphoshatidylinositol (GPI) anchor biosynthesis pathway cause Multiple Congenital Anomalies-Hypotonia-Seizures syndrome 1 (MCAHS1). The syndrome manifests developmental delay, hypotonia, and epilepsy, combined with multiple congenital anomalies. We report on the identification of a homozygous novel c.755A>T (p.D252V) deleterious mutation in a patient with Israeli-Arab origin with MCAHS1. The mutated PIGN caused a significant decrease of the overall GPI-anchored proteins and CD24 expression. Our results, strongly support previously published data, that partial depletion of GPI-anchored proteins is sufficient to cause severe phenotypic expression.
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Affiliation(s)
- Morad Khayat
- Genetics Institute, Ha'Emek Medical center, Afula, Israel
| | - Joseph Mark Tilghman
- Center for Complex Disease Genomics, McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | | | - Lucia Zalman
- The Hematology Laboratory, Ha'Emek Medical center, Afula, Israel
| | - Aravinda Chakravarti
- Center for Complex Disease Genomics, McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Stavit A Shalev
- Genetics Institute, Ha'Emek Medical center, Afula, Israel.,Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
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30
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Quantitative profiling of brain lipid raft proteome in a mouse model of fragile X syndrome. PLoS One 2015; 10:e0121464. [PMID: 25849048 PMCID: PMC4388542 DOI: 10.1371/journal.pone.0121464] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Accepted: 02/12/2015] [Indexed: 11/19/2022] Open
Abstract
Fragile X Syndrome, a leading cause of inherited intellectual disability and autism, arises from transcriptional silencing of the FMR1 gene encoding an RNA-binding protein, Fragile X Mental Retardation Protein (FMRP). FMRP can regulate the expression of approximately 4% of brain transcripts through its role in regulation of mRNA transport, stability and translation, thus providing a molecular rationale for its potential pleiotropic effects on neuronal and brain circuitry function. Several intracellular signaling pathways are dysregulated in the absence of FMRP suggesting that cellular deficits may be broad and could result in homeostatic changes. Lipid rafts are specialized regions of the plasma membrane, enriched in cholesterol and glycosphingolipids, involved in regulation of intracellular signaling. Among transcripts targeted by FMRP, a subset encodes proteins involved in lipid biosynthesis and homeostasis, dysregulation of which could affect the integrity and function of lipid rafts. Using a quantitative mass spectrometry-based approach we analyzed the lipid raft proteome of Fmr1 knockout mice, an animal model of Fragile X syndrome, and identified candidate proteins that are differentially represented in Fmr1 knockout mice lipid rafts. Furthermore, network analysis of these candidate proteins reveals connectivity between them and predicts functional connectivity with genes encoding components of myelin sheath, axonal processes and growth cones. Our findings provide insight to aid identification of molecular and cellular dysfunctions arising from Fmr1 silencing and for uncovering shared pathologies between Fragile X syndrome and other autism spectrum disorders.
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31
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Fujiwara I, Murakami Y, Niihori T, Kanno J, Hakoda A, Sakamoto O, Okamoto N, Funayama R, Nagashima T, Nakayama K, Kinoshita T, Kure S, Matsubara Y, Aoki Y. Mutations in PIGL in a patient with Mabry syndrome. Am J Med Genet A 2015; 167A:777-85. [PMID: 25706356 DOI: 10.1002/ajmg.a.36987] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 12/08/2014] [Indexed: 12/14/2022]
Abstract
Mabry syndrome, hyperphosphatasia mental retardation syndrome (HPMRS), is an autosomal recessive disease characterized by increased serum levels of alkaline phosphatase (ALP), severe developmental delay, intellectual disability, and seizures. Recent studies have revealed mutations in PIGV, PIGW, PIGO, PGAP2, and PGAP3 (genes that encode molecules of the glycosylphosphatidylinositol (GPI)-anchor biosynthesis pathway) in patients with HPMRS. We performed whole-exome sequencing of a patient with severe intellectual disability, distinctive facial appearance, fragile nails, and persistent increased serum levels of ALP. The result revealed a compound heterozygote with a 13-bp deletion in exon 1 (c.36_48del) and a two-base deletion in exon 2 (c.254_255del) in phosphatidylinositol glycan anchor, class L (PIGL) that caused frameshifts resulting in premature terminations. The 13-bp deletion was inherited from the father, and the two-base deletion was inherited from the mother. Expressing c.36_48del or c.254_255del cDNA with an HA-tag at the C- or N-terminus in PIGL-deficient CHO cells only partially restored the surface expression of GPI-anchored proteins (GPI-APs). Nonsynonymous changes or frameshift mutations in PIGL have been identified in patients with CHIME syndrome, a rare autosomal recessive disorder characterized by colobomas, congenital heart defects, early onset migratory ichthyosiform dermatosis, intellectual disability, and ear abnormalities. Our patient did not have colobomas, congenital heart defects, or early onset migratory ichthyosiform dermatosis and hence was diagnosed with HPMRS, and not CHIME syndrome. These results suggest that frameshift mutations that result in premature termination in PIGL cause a phenotype that is consistent with HPMRS.
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Affiliation(s)
- Ikuma Fujiwara
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
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32
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Marcucci G, Cianferotti L, Beck-Peccoz P, Capezzone M, Cetani F, Colao A, Davì MV, degli Uberti E, Del Prato S, Elisei R, Faggiano A, Ferone D, Foresta C, Fugazzola L, Ghigo E, Giacchetti G, Giorgino F, Lenzi A, Malandrino P, Mannelli M, Marcocci C, Masi L, Pacini F, Opocher G, Radicioni A, Tonacchera M, Vigneri R, Zatelli MC, Brandi ML. Rare diseases in clinical endocrinology: a taxonomic classification system. J Endocrinol Invest 2015; 38:193-259. [PMID: 25376364 DOI: 10.1007/s40618-014-0202-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 10/17/2014] [Indexed: 02/05/2023]
Abstract
PURPOSE Rare endocrine-metabolic diseases (REMD) represent an important area in the field of medicine and pharmacology. The rare diseases of interest to endocrinologists involve all fields of endocrinology, including rare diseases of the pituitary, thyroid and adrenal glands, paraganglia, ovary and testis, disorders of bone and mineral metabolism, energy and lipid metabolism, water metabolism, and syndromes with possible involvement of multiple endocrine glands, and neuroendocrine tumors. Taking advantage of the constitution of a study group on REMD within the Italian Society of Endocrinology, consisting of basic and clinical scientists, a document on the taxonomy of REMD has been produced. METHODS AND RESULTS This document has been designed to include mainly REMD manifesting or persisting into adulthood. The taxonomy of REMD of the adult comprises a total of 166 main disorders, 338 including all variants and subtypes, described into 11 tables. CONCLUSIONS This report provides a complete taxonomy to classify REMD of the adult. In the future, the creation of registries of rare endocrine diseases to collect data on cohorts of patients and the development of common and standardized diagnostic and therapeutic pathways for each rare endocrine disease is advisable. This will help planning and performing intervention studies in larger groups of patients to prove the efficacy, effectiveness, and safety of a specific treatment.
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Affiliation(s)
- G Marcucci
- Head, Bone Metablic Diseases Unit, Department of Surgery and Translational Medicine, University of Florence, Viale Pieraccini 6, 50139, Florence, Italy.
| | - L Cianferotti
- Head, Bone Metablic Diseases Unit, Department of Surgery and Translational Medicine, University of Florence, Viale Pieraccini 6, 50139, Florence, Italy
| | - P Beck-Peccoz
- Department of Clinical Sciences and Community Health, University of Milan and Endocrine Unit, Fondazione IRCCS Ca' Granda, Milan, Italy
| | - M Capezzone
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Endocrinology and Metabolism and Biochemistry, University of Siena, Policlinico Santa Maria alle Scotte, Siena, Italy
| | - F Cetani
- Unit of Endocrinology, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - A Colao
- Dipartimento di Medicina Clinica e Chirurgia, Università Federico II di Napoli, Naples, Italy
| | - M V Davì
- Section D, Department of Medicine, Clinic of Internal Medicine, University of Verona, Verona, Italy
| | - E degli Uberti
- Section of Endocrinology, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - S Del Prato
- Section of Metabolic Diseases and Diabetes, Department of Endocrinology and Metabolism, University of Pisa, Pisa, Italy
| | - R Elisei
- Unit of Endocrinology, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - A Faggiano
- Dipartimento di Medicina Clinica e Chirurgia, Università Federico II di Napoli, Naples, Italy
| | - D Ferone
- Endocrinology, Department of Internal Medicine and Medical Specialties and Center of Excellence for Biomedical Research, IRCCS AOU San Martino-IST, University of Genoa, Genoa, Italy
| | - C Foresta
- Department of Medicine and Centre for Human Reproduction Pathology, University of Padova, Padua, Italy
| | - L Fugazzola
- Department of Clinical Sciences and Community Health, University of Milan and Endocrine Unit, Fondazione IRCCS Ca' Granda, Milan, Italy
| | - E Ghigo
- Division of Endocrinology, Diabetology and Metabolism Department of Medical Sciences, University Hospital Città Salute e Scienza, Turin, Italy
| | - G Giacchetti
- Division of Endocrinology, Azienda Ospedaliero-Universitaria, Ospedali Riuniti Umberto I-GM Lancisi-G Salesi, Università Politecnica delle Marche, Ancona, Italy
| | - F Giorgino
- Section of Internal Medicine, Endocrinology, Andrology and Metabolic Diseases, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
| | - A Lenzi
- Chair of Endocrinology, Section Medical Pathophysiology, Food Science and Endocrinology, Department Exp. Medicine, Sapienza University of Rome, Policlinico Umberto I, Rome, Italy
| | - P Malandrino
- Endocrinology, Department of Clinical and Molecular Biomedicine, Garibaldi-Nesima Medical Center, University of Catania, Catania, Italy
| | - M Mannelli
- Endocrinology Unit, Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - C Marcocci
- Department of Endocrinology and Metabolism, University of Pisa, Pisa, Italy
| | - L Masi
- Department of Orthopedic, Metabolic Bone Diseases Unit AOUC-Careggi Hospital, Largo Palagi, 1, Florence, Italy
| | - F Pacini
- Section of Endocrinology and Metabolism, University of Siena, Siena, Italy
| | - G Opocher
- Familial Cancer Clinic and Oncoendocrinology, Veneto Institute of Oncology, IRCCS, Padua, Italy
- Department of Medicine DIMED, University of Padova, Padova, Italy
| | - A Radicioni
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | - M Tonacchera
- Unit of Endocrinology, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - R Vigneri
- Department of Clinical and Molecular Biomedicine, University of Catania, and Humanitas Catania Center of Oncology, Catania, Italy
| | - M C Zatelli
- Section of Endocrinology, Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - M L Brandi
- Head, Bone Metablic Diseases Unit, Department of Surgery and Translational Medicine, University of Florence, Viale Pieraccini 6, 50139, Florence, Italy.
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Abstract
An autosomal recessive syndrome of hyperphosphatasia (elevated circulating alkaline phosphatase (AP), seizures and neurologic deficits) was first described by Mabry and colleagues in 1970. Over the ensuing four decades, few cases were reported. In 2010, however, new families were identified and the syndromic nature of the disorder confirmed. Shortly thereafter, next generation sequencing was used to characterize causative defects in the glycosyl phosphatidylinositol (GPI) biosynthetic pathway, based partly on our understanding of how AP is anchored by GPI to the plasma membrane. Whether the seizures and cognitive defects seen in Mabry syndrome patients are attributable in part to the constant hyperphosphatasia is not known, as there are more than 250 other proteins dependent on GPI for their anchoring to the plasma membrane. However, Mabry syndrome may provide a new window on AP function in growth and development.
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Affiliation(s)
- David E C Cole
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada,
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34
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Exome sequencing identifies a recessive PIGN splice site mutation as a cause of syndromic congenital diaphragmatic hernia. Eur J Med Genet 2014; 57:487-93. [PMID: 24852103 DOI: 10.1016/j.ejmg.2014.05.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2014] [Accepted: 05/11/2014] [Indexed: 02/07/2023]
Abstract
Using exome sequencing we identify a homozygous splice site mutation in the PIGN gene in a foetus with multiple congenital anomalies including bilateral diaphragmatic hernia, cardiovascular anomalies, segmental renal dysplasia, facial dysmorphism, cleft palate, and oligodactyly. This finding expands the phenotypic spectrum associated with homozygous loss of function mutations in PIGN, and adds further support for defective GPI anchor biosynthesis as a cause of developmental abnormalities. We demonstrate that exome sequencing is a valuable approach for the identification of a genetic cause in sporadic cases of multiple congenital anomalies (MCA) due to inherited mutations.
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35
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Wolfe LA, Krasnewich D. Congenital disorders of glycosylation and intellectual disability. ACTA ACUST UNITED AC 2014; 17:211-25. [PMID: 23798010 DOI: 10.1002/ddrr.1115] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/17/2012] [Indexed: 12/31/2022]
Abstract
The congenital disorders of glycosylation (CDG) are a rapidly growing group of inborn errors of metabolism that result from defects in the synthesis of glycans. Glycosylation is a major post-translational protein modification and an estimated 2% of the human genome encodes proteins for glycosylation. The molecular bases for the current 60 disorders, affecting approximately 800 individuals, have been identified, many in the last 5 years. CDG should be considered in any multi-system syndrome or single tissue disorder not explained by the identification of another disorder. The initial clinical presentation varies significantly among individuals, even between affected siblings. However, two thirds of the known CDGs are associated with intellectual disabilities and most affected individuals need support services throughout their lives. Additional disorders of glycosylation are likely to be characterized over time.
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Affiliation(s)
- Lynne A Wolfe
- Genetic Nurse Practitioner, Undiagnosed Diseases Program, National Human Genome Research Institute, Bethesda, Maryland 20892, USA.
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36
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Swoboda KJ, Margraf RL, Carey JC, Zhou H, Newcomb TM, Coonrod E, Durtschi J, Mallempati K, Kumanovics A, Katz BE, Voelkerding KV, Opitz JM. A novel germline PIGA mutation in Ferro-Cerebro-Cutaneous syndrome: a neurodegenerative X-linked epileptic encephalopathy with systemic iron-overload. Am J Med Genet A 2013; 164A:17-28. [PMID: 24259288 DOI: 10.1002/ajmg.a.36189] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 07/25/2013] [Indexed: 01/22/2023]
Abstract
Three related males presented with a newly recognized x-linked syndrome associated with neurodegeneration, cutaneous abnormalities, and systemic iron overload. Linkage studies demonstrated that they shared a haplotype on Xp21.3-Xp22.2 and exome sequencing was used to identify candidate variants. Of the segregating variants, only a PIGA mutation segregated with disease in the family. The c.328_330delCCT PIGA variant predicts, p.Leu110del (or c.1030_1032delCTT, p.Leu344del depending on the reference sequence). The unaffected great-grandfather shared his X allele with the proband but he did not have the PIGA mutation, indicating that the mutation arose de novo in his daughter. A single family with a germline PIGA mutation has been reported; affected males had a phenotype characterized by multiple congenital anomalies and severe neurologic impairment resulting in infantile lethality. In contrast, affected boys in the family described here were born without anomalies and were neurologically normal prior to onset of seizures after 6 months of age, with two surviving to the second decade. PIGA encodes an enzyme in the GPI anchor biosynthesis pathway. An affected individual in the family studied here was deficient in GPI anchor proteins on granulocytes but not erythrocytes. In conclusion, the PIGA mutation in this family likely causes a reduction in GPI anchor protein cell surface expression in various cell types, resulting in the observed pleiotropic phenotype involving central nervous system, skin, and iron metabolism.
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Affiliation(s)
- Kathryn J Swoboda
- Pediatric Motor Disorders Research Program, Department of Neurology, University of Utah School of Medicine, Salt Lake City, Utah
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37
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Horn D, Wieczorek D, Metcalfe K, Barić I, Paležac L, Cuk M, Petković Ramadža D, Krüger U, Demuth S, Heinritz W, Linden T, Koenig J, Robinson PN, Krawitz P. Delineation of PIGV mutation spectrum and associated phenotypes in hyperphosphatasia with mental retardation syndrome. Eur J Hum Genet 2013; 22:762-7. [PMID: 24129430 DOI: 10.1038/ejhg.2013.241] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 09/13/2013] [Accepted: 09/18/2013] [Indexed: 11/09/2022] Open
Abstract
Three different genes of the glycosylphosphatidylinositol anchor synthesis pathway, PIGV, PIGO, and PGAP2, have recently been implicated in hyperphosphatasia-mental retardation syndrome (HPMRS), also known as Mabry syndrome, a rare autosomal recessive form of intellectual disability. The aim of this study was to delineate the PIGV mutation spectrum as well as the associated phenotypic spectrum in a cohort of 16 individuals diagnosed with HPMRS on the basis of intellectual disability and elevated serum alkaline phosphate as minimal diagnostic criteria. All PIGV exons and intronic boundaries were sequenced in 16 individuals. Biallelic PIGV mutations were identified in 8 of 16 unrelated families with HPMRS. The most frequent mutation detected in about 80% of affected families including the cases reported here is the c.1022C>A PIGV mutation, which was found in both the homozygous as well as the heterozygous state. Four further mutations found in this study (c. 176T>G, c.53G>A, c.905T>C, and c.1405C>T) are novel. Our findings in the largest reported cohort to date significantly extend the range of reported manifestations associated with PIGV mutations and demonstrate that the severe end of the clinical spectrum presents as a multiple congenital malformation syndrome with a high frequency of Hirschsprung disease, vesicoureteral, and renal anomalies as well as anorectal malformations. PIGV mutations are the major cause of HPMRS, which displays a broad clinical variability regarding associated malformations and growth patterns. Severe developmental delays, particular facial anomalies, brachytelephalangy, and hyperphosphatasia are consistently found in PIGV-positive individuals.
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Affiliation(s)
- Denise Horn
- Institut für Medizinische Genetik und Humangenetik, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Dagmar Wieczorek
- Institut für Humangenetik Essen, Universitätsklinikum Essen, Essen, Germany
| | - Kay Metcalfe
- Clinical Genetics, Genetic Medicine, St Mary's Hospital, Manchester, UK
| | - Ivo Barić
- 1] Department of Pediatrics, University Hospital Center Zagreb, Zagreb, Croatia [2] University of Zagreb, School of Medicine, Zagreb, Croatia
| | - Lidija Paležac
- University of Zagreb, School of Medicine, Zagreb, Croatia
| | - Mario Cuk
- 1] Department of Pediatrics, University Hospital Center Zagreb, Zagreb, Croatia [2] University of Zagreb, School of Medicine, Zagreb, Croatia
| | | | - Ulrike Krüger
- Institut für Medizinische Genetik und Humangenetik, Charité Universitätsmedizin Berlin, Berlin, Germany
| | | | | | - Tobias Linden
- Klinik für Kinder- und Jugendmedizin, Universitätsklinikum Münster, Münster, Germany
| | - Jens Koenig
- Klinik für Kinder- und Jugendmedizin, Universitätsklinikum Münster, Münster, Germany
| | - Peter N Robinson
- Institut für Medizinische Genetik und Humangenetik, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Peter Krawitz
- Institut für Medizinische Genetik und Humangenetik, Charité Universitätsmedizin Berlin, Berlin, Germany
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38
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Kvarnung M, Nilsson D, Lindstrand A, Korenke GC, Chiang SCC, Blennow E, Bergmann M, Stödberg T, Mäkitie O, Anderlid BM, Bryceson YT, Nordenskjöld M, Nordgren A. A novel intellectual disability syndrome caused by GPI anchor deficiency due to homozygous mutations inPIGT. J Med Genet 2013; 50:521-8. [DOI: 10.1136/jmedgenet-2013-101654] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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39
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Krawitz P, Murakami Y, Rieß A, Hietala M, Krüger U, Zhu N, Kinoshita T, Mundlos S, Hecht J, Robinson P, Horn D. PGAP2 mutations, affecting the GPI-anchor-synthesis pathway, cause hyperphosphatasia with mental retardation syndrome. Am J Hum Genet 2013; 92:584-9. [PMID: 23561847 DOI: 10.1016/j.ajhg.2013.03.011] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 01/28/2013] [Accepted: 03/15/2013] [Indexed: 01/02/2023] Open
Abstract
Recently, mutations in genes involved in the biosynthesis of the glycosylphosphatidylinositol (GPI) anchor have been identified in a new subclass of congenital disorders of glycosylation (CDGs) with a distinct spectrum of clinical features. To date, mutations have been identified in six genes (PIGA, PIGL, PIGM, PIGN, PIGO, and PIGV) encoding proteins in the GPI-anchor-synthesis pathway in individuals with severe neurological features, including seizures, muscular hypotonia, and intellectual disability. We developed a diagnostic gene panel for targeting all known genes encoding proteins in the GPI-anchor-synthesis pathway to screen individuals matching these features, and we detected three missense mutations in PGAP2, c.46C>T, c.380T>C, and c.479C>T, in two unrelated individuals with hyperphosphatasia with mental retardation syndrome (HPMRS). The mutations cosegregated in the investigated families. PGAP2 is involved in fatty-acid GPI-anchor remodeling, which occurs in the Golgi apparatus and is required for stable association between GPI-anchored proteins and the cell-surface membrane rafts. Transfection of the altered protein constructs, p.Arg16Trp (NP_001243169.1), p.Leu127Ser, and p.Thr160Ile, into PGAP2-null cells showed only partial restoration of GPI-anchored marker proteins, CD55 and CD59, on the cell surface. In this work, we show that an impairment of GPI-anchor remodeling also causes HPMRS and conclude that targeted sequencing of the genes encoding proteins in the GPI-anchor-synthesis pathway is an effective diagnostic approach for this subclass of CDGs.
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40
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Hansen L, Tawamie H, Murakami Y, Mang Y, ur Rehman S, Buchert R, Schaffer S, Muhammad S, Bak M, Nöthen MM, Bennett EP, Maeda Y, Aigner M, Reis A, Kinoshita T, Tommerup N, Baig SM, Abou Jamra R. Hypomorphic mutations in PGAP2, encoding a GPI-anchor-remodeling protein, cause autosomal-recessive intellectual disability. Am J Hum Genet 2013; 92:575-83. [PMID: 23561846 DOI: 10.1016/j.ajhg.2013.03.008] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Revised: 02/11/2013] [Accepted: 03/12/2013] [Indexed: 12/28/2022] Open
Abstract
PGAP2 encodes a protein involved in remodeling the glycosylphosphatidylinositol (GPI) anchor in the Golgi apparatus. After synthesis in the endoplasmic reticulum (ER), GPI anchors are transferred to the proteins and are remodeled while transported through the Golgi to the cell membrane. Germline mutations in six genes (PIGA, PIGL, PIGM, PIGV, PIGN, and PIGO) in the ER-located part of the GPI-anchor-biosynthesis pathway have been reported, and all are associated with phenotypes extending from malformation and lethality to severe intellectual disability, epilepsy, minor dysmorphisms, and elevated alkaline phosphatase (ALP). We performed autozygosity mapping and ultra-deep sequencing followed by stringent filtering and identified two homozygous PGAP2 alterations, p.Tyr99Cys and p.Arg177Pro, in seven offspring with nonspecific autosomal-recessive intellectual disability from two consanguineous families. Rescue experiments with the altered proteins in PGAP2-deficient Chinese hamster ovary cell lines showed less expression of cell-surface GPI-anchored proteins DAF and CD59 than of the wild-type protein, substantiating the pathogenicity of the identified alterations. Furthermore, we observed a full rescue when we used strong promoters before the mutant cDNAs, suggesting a hypomorphic effect of the mutations. We report on alterations in the Golgi-located part of the GPI-anchor-biosynthesis pathway and extend the phenotypic spectrum of the GPI-anchor deficiencies to isolated intellectual disability with elevated ALP. GPI-anchor deficiencies can be interpreted within the concept of a disease family, and we propose that the severity of the phenotype is dependent on the location of the altered protein in the biosynthesis chain.
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Affiliation(s)
- Lars Hansen
- Wilhelm Johannsen Centre for Functional Genome Research, The Panum Institute, University of Copenhagen, Blegdamsvej 3B, DK-2200 Copenhagen N, Denmark.
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41
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Diseases of glycosylation beyond classical congenital disorders of glycosylation. Biochim Biophys Acta Gen Subj 2012; 1820:1306-17. [DOI: 10.1016/j.bbagen.2012.02.001] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 01/31/2012] [Accepted: 02/02/2012] [Indexed: 12/30/2022]
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42
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Zeevaert R, de Zegher F, Sturiale L, Garozzo D, Smet M, Moens M, Matthijs G, Jaeken J. Bone Dysplasia as a Key Feature in Three Patients with a Novel Congenital Disorder of Glycosylation (CDG) Type II Due to a Deep Intronic Splice Mutation in TMEM165. JIMD Rep 2012; 8:145-52. [PMID: 23430531 DOI: 10.1007/8904_2012_172] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Revised: 07/21/2012] [Accepted: 07/25/2012] [Indexed: 01/05/2023] Open
Abstract
Three patients belonging to two families presented with a psychomotor-dysmorphism syndrome including postnatal growth deficiency and major spondylo-, epi-, and metaphyseal skeletal involvement. Other features were muscular hypotrophy, fat excess, partial growth hormone deficiency, and, in two of the three patients, episodes of unexplained fever. Additional investigations showed mild to moderate increases of serum transaminases (particularly of aspartate transaminase (AST)), creatine kinase (CK), and lactate dehydrogenase (LDH), as well as decreased coagulation factors VIII, IX, XI, and protein C. Diagnostic work-up revealed a type 2 serum transferrin isoelectrofocusing (IEF) pattern and a cathodal shift on apolipoprotein C-III IEF pointing to a combined N- and O-glycosylation defect. Known glycosylation disorders with similar N-glycan structures lacking galactose and sialic acid were excluded. Through a combination of homozygosity mapping and expression profiling, a deep intronic homozygous mutation (c.792 + 182G>A) was found in TMEM165 (TPARL) in the three patients. TMEM165 is a gene of unknown function, possibly involved in Golgi proton/calcium transport. Here we present a detailed clinical description of the three patients with this mutation. The TMEM165 deficiency represents a novel type of CDG (TMEM165-CDG). This disorder enlarges the group of CDG caused by deficiencies in proteins that are not specifically involved in glycosylation but that have functions in the organization and homeostasis of the intracellular compartments and the secretory pathway, like COG-CDG and ATP6V0A2-CDG.
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Affiliation(s)
- R Zeevaert
- Center for Metabolic Disease, Department of Pediatrics, Katholieke Universiteit Leuven, Leuven, Belgium
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43
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Mutations in PIGO, a member of the GPI-anchor-synthesis pathway, cause hyperphosphatasia with mental retardation. Am J Hum Genet 2012; 91:146-51. [PMID: 22683086 DOI: 10.1016/j.ajhg.2012.05.004] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 04/19/2012] [Accepted: 05/11/2012] [Indexed: 11/23/2022] Open
Abstract
Hyperphosphatasia with mental retardation syndrome (HPMRS), an autosomal-recessive form of intellectual disability characterized by facial dysmorphism, seizures, brachytelephalangy, and persistent elevated serum alkaline phosphatase (hyperphosphatasia), was recently shown to be caused by mutations in PIGV, a member of the glycosylphosphatidylinositol (GPI)-anchor-synthesis pathway. However, not all individuals with HPMRS harbor mutations in this gene. By exome sequencing, we detected compound-heterozygous mutations in PIGO, a gene coding for a membrane protein of the same molecular pathway, in two siblings with HPMRS, and we then found by Sanger sequencing further mutations in another affected individual; these mutations cosegregated in the investigated families. The mutant transcripts are aberrantly spliced, decrease the membrane stability of the protein, or impair enzyme function such that GPI-anchor synthesis is affected and the level of GPI-anchored substrates localized at the cell surface is reduced. Our data identify PIGO as the second gene associated with HPMRS and suggest that a deficiency in GPI-anchor synthesis is the underlying molecular pathomechanism of HPMRS.
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44
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Thompson MD, Roscioli T, Marcelis C, Nezarati MM, Stolte-Dijkstra I, Sharom FJ, Lu P, Phillips JA, Sweeney E, Robinson PN, Krawitz P, Yntema HG, Andrade DM, Brunner HG, Cole DE. Phenotypic variability in hyperphosphatasia with seizures and neurologic deficit (Mabry syndrome). Am J Med Genet A 2012; 158A:553-8. [DOI: 10.1002/ajmg.a.35202] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 12/01/2011] [Indexed: 11/06/2022]
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