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Muthusamy K, Sivadasan A, Dixon L, Sudhakar S, Thomas M, Danda S, Wszolek ZK, Wierenga K, Dhamija R, Gavrilova R. Adult-onset leukodystrophies: a practical guide, recent treatment updates, and future directions. Front Neurol 2023; 14:1219324. [PMID: 37564735 PMCID: PMC10410460 DOI: 10.3389/fneur.2023.1219324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 06/19/2023] [Indexed: 08/12/2023] Open
Abstract
Adult-onset leukodystrophies though individually rare are not uncommon. This group includes several disorders with isolated adult presentations, as well as several childhood leukodystrophies with attenuated phenotypes that present at a later age. Misdiagnoses often occur due to the clinical and radiological overlap with common acquired disorders such as infectious, immune, inflammatory, vascular, metabolic, and toxic etiologies. Increased prevalence of non-specific white matter changes in adult population poses challenges during diagnostic considerations. Clinico-radiological spectrum and molecular landscape of adult-onset leukodystrophies have not been completely elucidated at this time. Diagnostic approach is less well-standardized when compared to the childhood counterpart. Absence of family history and reduced penetrance in certain disorders frequently create a dilemma. Comprehensive evaluation and molecular confirmation when available helps in prognostication, early initiation of treatment in certain disorders, enrollment in clinical trials, and provides valuable information for the family for reproductive counseling. In this review article, we aimed to formulate an approach to adult-onset leukodystrophies that will be useful in routine practice, discuss common adult-onset leukodystrophies with usual and unusual presentations, neuroimaging findings, recent advances in treatment, acquired mimics, and provide an algorithm for comprehensive clinical, radiological, and genetic evaluation that will facilitate early diagnosis and consider active treatment options when available. A high index of suspicion, awareness of the clinico-radiological presentations, and comprehensive genetic evaluation are paramount because treatment options are available for several disorders when diagnosed early in the disease course.
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Affiliation(s)
- Karthik Muthusamy
- Department of Clinical Genomics, Mayo Clinic, Jacksonville, FL, United States
| | - Ajith Sivadasan
- Department of Neurological Sciences, Christian Medical College, Tamil Nadu, Vellore, India
| | - Luke Dixon
- Department of Radiology, Imperial College, NHS Trust, London, United Kingdom
| | - Sniya Sudhakar
- Department of Radiology, Great Ormond Street Hospital, London, United Kingdom
| | - Maya Thomas
- Department of Neurological Sciences, Christian Medical College, Tamil Nadu, Vellore, India
| | - Sumita Danda
- Department of Medical Genetics, Christian Medical College, Vellore, Tamil Nadu, India
| | | | - Klaas Wierenga
- Department of Clinical Genomics, Mayo Clinic, Jacksonville, FL, United States
| | - Radhika Dhamija
- Department of Clinical Genomics and Neurology, Mayo Clinic, Phoenix, AZ, United States
| | - Ralitza Gavrilova
- Department of Clinical Genomics and Neurology, Mayo Clinic, Rochester, MN, United States
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Dohr KA, Tokic S, Gastager-Ehgartner M, Stojakovic T, Dumic M, Plecko B, Dumic KK. Two Single Nucleotide Deletions in the ABCD1 Gene Causing Distinct Phenotypes of X-Linked Adrenoleukodystrophy. Int J Mol Sci 2023; 24:ijms24065957. [PMID: 36983033 PMCID: PMC10051867 DOI: 10.3390/ijms24065957] [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: 12/31/2022] [Revised: 03/02/2023] [Accepted: 03/06/2023] [Indexed: 03/30/2023] Open
Abstract
X-linked adrenoleukodystrophy (X-ALD) is a rare inborn error of the peroxisomal metabolism caused by pathologic variants in the ATP-binding cassette transporter type D, member 1 (ABCD1) gene located on the X-chromosome. ABCD1 protein, also known as adrenoleukodystrophy protein, is responsible for transport of the very long chain fatty acids (VLCFA) from cytoplasm into the peroxisomes. Therefore, altered function or lack of the ABCD1 protein leads to accumulation of VLCFA in various tissues and blood plasma leading to either rapidly progressive leukodystrophy (cerebral ALD), progressive adrenomyeloneuropathy (AMN), or isolated primary adrenal insufficiency (Addison's disease). We report two distinct single nucleotide deletions in the ABCD1 gene, c.253delC [p.Arg85Glyfs*18] in exon 1, leading to both cerebral ALD and to AMN phenotype in one family, and c.1275delA [p.Phe426Leufs*15] in exon 4, leading to AMN and primary adrenal insufficiency in a second family. For the latter variant, we demonstrate reduced mRNA expression and a complete absence of the ABCD1 protein in PBMC. Distinct mRNA and protein expression in the index patient and heterozygous carriers does not associate with VLCFA concentration in plasma, which is in line with the absence of genotype-phenotype correlation in X-ALD.
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Affiliation(s)
- Katrin A Dohr
- Research Unit of Analytical Mass Spectrometry, Cell Biology and Biochemistry of Inborn Errors of Metabolism, Department of Paediatrics and Adolescent Medicine, Medical University of Graz, 8036 Graz, Austria
| | - Silvija Tokic
- Research Unit of Analytical Mass Spectrometry, Cell Biology and Biochemistry of Inborn Errors of Metabolism, Department of Paediatrics and Adolescent Medicine, Medical University of Graz, 8036 Graz, Austria
| | - Magdalena Gastager-Ehgartner
- Research Unit of Analytical Mass Spectrometry, Cell Biology and Biochemistry of Inborn Errors of Metabolism, Department of Paediatrics and Adolescent Medicine, Medical University of Graz, 8036 Graz, Austria
| | - Tatjana Stojakovic
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, University Hospital Graz, 8036 Graz, Austria
| | - Miroslav Dumic
- Department of Paediatric Endocrinology and Diabetes, Clinical Hospital Centre Zagreb, 10000 Zagreb, Croatia
| | - Barbara Plecko
- Division of General Paediatrics, Department of Paediatrics and Adolescent Medicine, Medical University of Graz, 8036 Graz, Austria
| | - Katja K Dumic
- Department of Paediatric Endocrinology and Diabetes, Clinical Hospital Centre Zagreb, 10000 Zagreb, Croatia
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Progressive Cognitive and Behavioral Changes With Leukodystrophy due to ABCD1 Gene Mutation. Dement Neurocogn Disord 2022; 21:162-164. [DOI: 10.12779/dnd.2022.21.4.162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 10/27/2022] [Accepted: 10/28/2022] [Indexed: 11/09/2022] Open
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