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Koens LH, Tijssen MAJ, Lange F, Wolffenbuttel BHR, Rufa A, Zee DS, de Koning TJ. Eye movement disorders and neurological symptoms in late-onset inborn errors of metabolism. Mov Disord 2018; 33:1844-1856. [PMID: 30485556 PMCID: PMC6587951 DOI: 10.1002/mds.27484] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 08/03/2018] [Accepted: 08/06/2018] [Indexed: 11/06/2022] Open
Abstract
Inborn errors of metabolism in adults are still largely unexplored. Despite the fact that adult‐onset phenotypes have been known for many years, little attention is given to these disorders in neurological practice. The adult‐onset presentation differs from childhood‐onset phenotypes, often leading to considerable diagnostic delay. The identification of these patients at the earliest stage of disease is important, given that early treatment may prevent or lessen further brain damage. Neurological and psychiatric symptoms occur more frequently in adult forms. Abnormalities of eye movements are also common and can be the presenting sign. Eye movement disorders can be classified as central or peripheral. Central forms are frequently observed in lysosomal storage disorders, whereas peripheral forms are a key feature of mitochondrial disease. Furthermore, oculogyric crisis is an important feature in disorders affecting dopamine syntheses or transport. Ocular motor disorders are often not reported by the patient, and abnormalities can be easily overlooked in a general examination. In adults with unexplained psychiatric and neurological symptoms, a special focus on examination of eye movements can serve as a relatively simple clinical tool to detect a metabolic disorder. Eye movements can be easily quantified and analyzed with video‐oculography, making them a valuable biomarker for following the natural course of disease or the response to therapies. Here, we review, for the first time, eye movement disorders that can occur in inborn errors of metabolism, with a focus on late‐onset forms. We provide a step‐by‐step overview that will help clinicians to examine and interpret eye movement disorders. © 2018 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Lisette H Koens
- University of Groningen, University Medical Center Groningen, Department of Neurology, Groningen, The Netherlands
| | - Marina A J Tijssen
- University of Groningen, University Medical Center Groningen, Department of Neurology, Groningen, The Netherlands
| | - Fiete Lange
- University of Groningen, University Medical Center Groningen, Department of Clinical Neurophysiology, Groningen, The Netherlands
| | - Bruce H R Wolffenbuttel
- Department of Endocrinology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Alessandra Rufa
- Department of Medicine Surgery and Neurosciences, University of Siena, Eye tracking and Visual Application Lab (EVA Lab)-Neurology and Neurometabolic Unit, Siena, Italy
| | - David S Zee
- Department of Neuroscience, Department of Ophthalmology, The Johns Hopkins University, The Johns Hopkins Hospital, Department of Neurology, Department of Otolaryngology-Head and Neck Surgery, Baltimore, Maryland, USA
| | - Tom J de Koning
- University of Groningen, Division of Metabolic Diseases, University Medical Center Groningen, Groningen, The Netherlands.,University of Groningen, Department of Genetics, University Medical Center Groningen, Groningen, The Netherlands
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Yadak R, Sillevis Smitt P, van Gisbergen MW, van Til NP, de Coo IFM. Mitochondrial Neurogastrointestinal Encephalomyopathy Caused by Thymidine Phosphorylase Enzyme Deficiency: From Pathogenesis to Emerging Therapeutic Options. Front Cell Neurosci 2017; 11:31. [PMID: 28261062 PMCID: PMC5309216 DOI: 10.3389/fncel.2017.00031] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 02/01/2017] [Indexed: 01/05/2023] Open
Abstract
Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a progressive metabolic disorder caused by thymidine phosphorylase (TP) enzyme deficiency. The lack of TP results in systemic accumulation of deoxyribonucleosides thymidine (dThd) and deoxyuridine (dUrd). In these patients, clinical features include mental regression, ophthalmoplegia, and fatal gastrointestinal complications. The accumulation of nucleosides also causes imbalances in mitochondrial DNA (mtDNA) deoxyribonucleoside triphosphates (dNTPs), which may play a direct or indirect role in the mtDNA depletion/deletion abnormalities, although the exact underlying mechanism remains unknown. The available therapeutic approaches include dialysis and enzyme replacement therapy, both can only transiently reverse the biochemical imbalance. Allogeneic hematopoietic stem cell transplantation is shown to be able to restore normal enzyme activity and improve clinical manifestations in MNGIE patients. However, transplant related complications and disease progression result in a high mortality rate. New therapeutic approaches, such as adeno-associated viral vector and hematopoietic stem cell gene therapy have been tested in Tymp-/-Upp1-/- mice, a murine model for MNGIE. This review provides background information on disease manifestations of MNGIE with a focus on current management and treatment options. It also outlines the pre-clinical approaches toward future treatment of the disease.
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Affiliation(s)
- Rana Yadak
- Department of Neurology, Erasmus University Medical Center Rotterdam, Netherlands
| | - Peter Sillevis Smitt
- Department of Neurology, Erasmus University Medical Center Rotterdam, Netherlands
| | - Marike W van Gisbergen
- Department of Radiation Oncology (MaastRO-Lab), GROW - School for Oncology and Developmental Biology, Maastricht University Medical Centre Maastricht, Netherlands
| | - Niek P van Til
- Laboratory of Translational Immunology, University Medical Center Utrecht Utrecht, Netherlands
| | - Irenaeus F M de Coo
- Department of Neurology, Erasmus University Medical Center Rotterdam, Netherlands
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Sivadasan A, Muthusamy K, Patil AK, Mathew V, Alexander M. Pearls & Oy-sters: Mitochondrial neurogastrointestinal encephalomyopathy: Diagnosis and response to peritoneal dialysis. Neurology 2016; 86:e147-e150. [PMID: 27044617 DOI: 10.1212/wnl.0000000000002536] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Ajith Sivadasan
- From the Department of Neurological Sciences, Christian Medical College, Vellore, India
| | - Karthik Muthusamy
- From the Department of Neurological Sciences, Christian Medical College, Vellore, India
| | - Anil Kumar Patil
- From the Department of Neurological Sciences, Christian Medical College, Vellore, India
| | - Vivek Mathew
- From the Department of Neurological Sciences, Christian Medical College, Vellore, India
| | - Mathew Alexander
- From the Department of Neurological Sciences, Christian Medical College, Vellore, India.
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