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Ilyas M, Holzwarth D, Ishaq R, Ali Y, Habiba U, Raja AM, Saeed S, Abdullah U, Khan SN, Ullah A, Raja GK, Baig SM, Fazeli W, Kunz WS, Shaiq PA. Whole-Exome sequencing identifies GYS2 biallelic variants in individuals with suspected epilepsy. Seizure 2024; 116:74-80. [PMID: 37574425 DOI: 10.1016/j.seizure.2023.07.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 07/04/2023] [Accepted: 07/25/2023] [Indexed: 08/15/2023] Open
Abstract
BACKGROUND Adequate glucose supply is essential for brain function, therefore hypoglycemic states may lead to seizures. Since blood glucose supply for brain is buffered by liver glycogen, an impairment of liver glycogen synthesis by mutations in the liver glycogen synthase gene (GYS2) might result in a substantial neurological involvement. Here, we describe the phenotypes of affected siblings of two families harboring biallelic mutations in GYS2. METHODS Two suspected families - a multiplex Pakistani family (family A) with three affected siblings and a family of Moroccan origin (family B) with a single affected child who presented with seizures and reduced fasting blood glucose levels were genetically characterized. Whole exome sequencing (WES) was performed on the index patients, followed by Sanger sequencing-based segregation analyses on all available members of both families. RESULTS The variant prioritization of WES and later Sanger sequencing confirmed three mutations in the GYS2 gene (12p12.1) consistent with an autosomal recessive pattern of inheritance. A homozygous splice acceptor site variant (NM_021957.3, c. 1646 -2A>G) segregated in family A. Two novel compound heterozygous variants (NM_021957.3: c.343G>A; p.Val115Met and NM_021957.3: c.875A>T; p.Glu292Val) were detected in family B, suggesting glycogen storage disorder. A special diet designed to avoid hypoglycemia, in addition to change of the anti-seizure medication led to reduction in seizure frequency. CONCLUSIONS This study suggests that the seizures in patients initially diagnosed with epilepsy might be directly caused, or influenced by hypoglycemia due to pathogenic variants in the GYS2 gene.
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Affiliation(s)
- Muhammad Ilyas
- University Institute of Biochemistry and Biotechnology, Pir Mehr Ali Arid Agriculture University Rawalpindi, Pakistan; Department of Medical laboratory technology, Riphah International University, Malakand Campus, Pakistan; Department of Epileptology, University of Bonn, Germany
| | - Dorothea Holzwarth
- Department of Neuropediatrics, Children's Hospital, University of Bonn, Germany
| | - Rafaqat Ishaq
- University Institute of Biochemistry and Biotechnology, Pir Mehr Ali Arid Agriculture University Rawalpindi, Pakistan
| | - Yasir Ali
- Institute of Chemistry, Slovak Academy of Sciences, 845 38 Bratislava, Slovakia
| | - Umme Habiba
- University Institute of Biochemistry and Biotechnology, Pir Mehr Ali Arid Agriculture University Rawalpindi, Pakistan
| | - Asad Mehmood Raja
- University Institute of Biochemistry and Biotechnology, Pir Mehr Ali Arid Agriculture University Rawalpindi, Pakistan
| | - Sadia Saeed
- University Institute of Biochemistry and Biotechnology, Pir Mehr Ali Arid Agriculture University Rawalpindi, Pakistan; Department of Clinical Molecular Biology, EpiGen, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Uzma Abdullah
- University Institute of Biochemistry and Biotechnology, Pir Mehr Ali Arid Agriculture University Rawalpindi, Pakistan
| | - Sadiq Noor Khan
- Department of Medical Laboratory Technology, University of Haripur, Khyber Pakhtunkhwa, Pakistan
| | - Ata Ullah
- Applied Genomics Centre and State Key Laboratory of Molecular Neuroscience, Hongkong University of Science and Technology, Division of Life Sciences, Hong Kong
| | - Ghazala Kaukab Raja
- University Institute of Biochemistry and Biotechnology, Pir Mehr Ali Arid Agriculture University Rawalpindi, Pakistan
| | | | - Walid Fazeli
- Department of Neuropediatrics, Children's Hospital, University of Bonn, Germany
| | | | - Pakeeza Arzoo Shaiq
- University Institute of Biochemistry and Biotechnology, Pir Mehr Ali Arid Agriculture University Rawalpindi, Pakistan.
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Vaudano AE, Olivotto S, Ruggieri A, Gessaroli G, Talami F, Parmeggiani A, De Giorgis V, Veggiotti P, Meletti S. The effect of chronic neuroglycopenia on resting state networks in GLUT1 syndrome across the lifespan. Hum Brain Mapp 2020; 41:453-466. [PMID: 31710770 PMCID: PMC7313681 DOI: 10.1002/hbm.24815] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 09/18/2019] [Accepted: 09/20/2019] [Indexed: 12/20/2022] Open
Abstract
Glucose transporter type I deficiency syndrome (GLUT1DS) is an encephalopathic disorder due to a chronic insufficient transport of glucose into the brain. PET studies in GLUT1DS documented a widespread cortico‐thalamic hypometabolism and a signal increase in the basal ganglia, regardless of age and clinical phenotype. Herein, we captured the pattern of functional connectivity of distinct striatal, cortical, and cerebellar regions in GLUT1DS (10 children, eight adults) and in healthy controls (HC, 19 children, 17 adults) during rest. Additionally, we explored for regional connectivity differences in GLUT1 children versus adults and according to the clinical presentation. Compared to HC, GLUT1DS exhibited increase connectivity within the basal ganglia circuitries and between the striatal regions with the frontal cortex and cerebellum. The excessive connectivity was predominant in patients with movement disorders and in children compared to adults, suggesting a correlation with the clinical phenotype and age at fMRI study. Our findings highlight the primary role of the striatum in the GLUT1DS pathophysiology and confirm the dependency of symptoms to the patients' chronological age. Despite the reduced chronic glucose uptake, GLUT1DS exhibit increased connectivity changes in regions highly sensible to glycopenia. Our results may portrait the effect of neuroprotective brain strategy to overcome the chronic poor energy supply during vulnerable ages.
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Affiliation(s)
- Anna Elisabetta Vaudano
- Neurology Unit, OCSAE Hospital, AOU Modena, Modena, Italy.,Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Sara Olivotto
- Pediatric Neurology Unit, V. Buzzi Hospital, University of Milan, Milan, Italy
| | - Andrea Ruggieri
- Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | | | - Francesca Talami
- Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Antonia Parmeggiani
- Child Neurology and Psychiatry Unit, Policlinico S. Orsola-Malpighi, Bologna, Italy.,Department of Medical and Surgical Sciences, University of Bologna, Italy
| | | | | | - Stefano Meletti
- Neurology Unit, OCSAE Hospital, AOU Modena, Modena, Italy.,Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
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