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Peng Q, Cui Y, Wu J, Wu L, Liu J, Han Y, Lu G. A c.726C>G (p.Tyr242Ter) nonsense mutation-associated with splicing alteration (NASA) of WDR45 gene underlies β-propeller protein-associated neurodegeneration (BPAN). Heliyon 2024; 10:e30438. [PMID: 38765101 PMCID: PMC11098806 DOI: 10.1016/j.heliyon.2024.e30438] [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: 01/27/2024] [Revised: 04/24/2024] [Accepted: 04/25/2024] [Indexed: 05/21/2024] Open
Abstract
Neurodegeneration with brain iron accumulation (NBIA) is a clinically and genetically heterogeneous disease characterized by increased iron deposition in the basal ganglia and progressive degeneration of the nervous system in adulthood. However, in early childhood, there were no characteristic features to perform early diagnosis. In our study, a female child exhibited global developmental delay, intellectual disability, and febrile seizure without other distinct clinical phenotypes. Through whole exome sequencing (WES), a de novo nonsense mutation (c.726C > G, p. Tyr242Ter) of WDR45 gene was identified in this child. She was finally diagnosed as β-propeller protein-associated neurodegeneration (BPAN), one of the recently identified subtypes of NBIA. This mutation could act as a premature stop codon (PSC) which rendered the mutated transcripts to be degraded by nonsense-mediated mRNA decay (NMD), leading to decreased levels of PSC-containing mRNAs. Additionally, through mini-gene splicing assays, this mutation could result in an unprecedented novel transcript with the exon 9 of WDR45 excluded by nonsense-associated splicing alteration (NASA). Transcriptome sequencing (RNA-seq) on total RNAs from PBMCs of the trio revealed three types of alternative splicing events in the patient. Further research implied that downregulation of iron transport genes (TFRC, TFR2, SCARA5) might be the underlying mechanism for the iron accumulation in patients with deficient WDR45. This is the first report about NASA happening in WDR45. It implies that nonsense mutations approximal to splicing sites could affect the disease pathogenesis through more than one molecular mechanism and should be taken into consideration when conducting genetic counseling.
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Affiliation(s)
- Qiongling Peng
- Department of Child Healthcare, Shenzhen Bao'an Women's and Children's Hospital, 56 Yulyu Road, Bao'an District, Shenzhen, 518000, China
| | - Ying Cui
- Department of Blood Transfusion, The First Affiliated Hospital of Xi'an Jiaotong University, No. 277 West Yanta Road, Xi'an, 710061, China
| | - Jin Wu
- Laboratory of Translational Medicine Research, Department of Pathology, Affiliated Deyang People's Hospital of Sichuan Traditional Medical University, No. 103 First Section of Taishanbei Road, Jingyang District, Deyang, 618000, China
- Deyang Key Laboratory of Tumor Molecular Research, No. 103 First Section of Taishanbei Road, Jingyang District, Deyang, 618000, China
| | - Lianying Wu
- Laboratory of Translational Medicine Research, Department of Pathology, Affiliated Deyang People's Hospital of Sichuan Traditional Medical University, No. 103 First Section of Taishanbei Road, Jingyang District, Deyang, 618000, China
- Deyang Key Laboratory of Tumor Molecular Research, No. 103 First Section of Taishanbei Road, Jingyang District, Deyang, 618000, China
| | - Jiajia Liu
- Department of Child Healthcare, Shenzhen Bao'an Women's and Children's Hospital, 56 Yulyu Road, Bao'an District, Shenzhen, 518000, China
| | - Yangyun Han
- Sichuan Clinical Medical Research Center for Neurological Diseases, No. 103 First Section of Taishanbei Road, Jingyang District, Deyang, 618000, China
| | - Guanting Lu
- Laboratory of Translational Medicine Research, Department of Pathology, Affiliated Deyang People's Hospital of Sichuan Traditional Medical University, No. 103 First Section of Taishanbei Road, Jingyang District, Deyang, 618000, China
- Deyang Key Laboratory of Tumor Molecular Research, No. 103 First Section of Taishanbei Road, Jingyang District, Deyang, 618000, China
- Sichuan Clinical Medical Research Center for Neurological Diseases, No. 103 First Section of Taishanbei Road, Jingyang District, Deyang, 618000, China
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Wilson JL, Gregory A, Kurian MA, Bushlin I, Mochel F, Emrick L, Adang L, Hogarth P, Hayflick SJ. Consensus clinical management guideline for beta-propeller protein-associated neurodegeneration. Dev Med Child Neurol 2021; 63:1402-1409. [PMID: 34347296 DOI: 10.1111/dmcn.14980] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/31/2021] [Indexed: 12/17/2022]
Abstract
This review provides recommendations for the evaluation and management of individuals with beta-propeller protein-associated neurodegeneration (BPAN). BPAN is one of several neurodegenerative disorders with brain iron accumulation along with pantothenate kinase-associated neurodegeneration, PLA2G6-associated neurodegeneration, mitochondrial membrane protein-associated neurodegeneration, fatty acid hydroxylase-associated neurodegeneration, and COASY protein-associated neurodegeneration. BPAN typically presents with global developmental delay and epilepsy in childhood, which is followed by the onset of dystonia and parkinsonism in mid-adolescence or adulthood. BPAN is an X-linked dominant disorder caused by pathogenic variants in WDR45, resulting in a broad clinical phenotype and imaging spectrum. This review, informed by an evaluation of the literature and expert opinion, discusses the clinical phenotype and progression of the disease, imaging findings, epilepsy features, and genetics, and proposes an approach to the initial evaluation and management of disease manifestations across the life span in individuals with BPAN. What this paper adds The complex epilepsy profile of beta-propeller protein-associated neurodegeneration (BPAN) often resolves in adolescence. The treatment for an individual with BPAN is supportive, with attention to sleep disorders, complex epilepsy, and behavioral problems. Individuals with BPAN have shifting needs throughout their life span requiring multidisciplinary care.
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Affiliation(s)
- Jenny L Wilson
- Division of Pediatric Neurology, Oregon Health & Science University, Portland, OR, USA
| | - Allison Gregory
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR, USA
| | - Manju A Kurian
- Molecular Neurosciences, Developmental Neurosciences Programme, UCL Institute of Child Health, London, UK
| | - Ittai Bushlin
- Division of Pediatric Neurology, Oregon Health & Science University, Portland, OR, USA
| | - Fanny Mochel
- Department of Genetics, Reference Center for Neurometabolic Diseases, Assistance Publique-Hôpitaux de Paris, University Hospital La Pitié Salpêtrière, Paris, France
| | - Lisa Emrick
- Division of Neurology and Developmental Neuroscience, Department of Pediatrics, Department of Human and Molecular Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Laura Adang
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | | | - Penelope Hogarth
- Departments of Molecular and Medical Genetics and Neurology, Oregon Health & Science University, Portland, OR, USA
| | - Susan J Hayflick
- Departments of Molecular and Medical Genetics, Pediatrics, and Neurology, Oregon Health & Science University, Portland, OR, USA
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Lee HE, Jung MK, Noh SG, Choi HB, Chae SH, Lee JH, Mun JY. Iron Accumulation and Changes in Cellular Organelles in WDR45 Mutant Fibroblasts. Int J Mol Sci 2021; 22:ijms222111650. [PMID: 34769084 PMCID: PMC8584078 DOI: 10.3390/ijms222111650] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 10/12/2021] [Accepted: 10/22/2021] [Indexed: 12/16/2022] Open
Abstract
Iron overload in the brain, defined as excess stores of iron, is known to be associated with neurological disorders. In neurodegeneration accompanied by brain iron accumulation, we reported a specific point mutation, c.974-1G>A in WD Repeat Domain 45 (WDR45), showing iron accumulation in the brain, and autophagy defects in the fibroblasts. In this study, we investigated whether fibroblasts with mutated WDR45 accumulated iron, and other effects on cellular organelles. We first identified the main location of iron accumulation in the mutant fibroblasts and then investigated the effects of this accumulation on cellular organelles, including lipid droplets, mitochondria and lysosomes. Ultrastructure analysis using transmission electron microscopy (TEM) and confocal microscopy showed structural changes in the organelles. Increased numbers of lipid droplets, fragmented mitochondria and increased numbers of lysosomal vesicles with functional disorder due to WDR45 deficiency were observed. Based on correlative light and electron microscopy (CLEM) findings, most of the iron accumulation was noted in the lysosomal vesicles. These changes were associated with defects in autophagy and defective protein and organelle turnover. Gene expression profiling analysis also showed remarkable changes in lipid metabolism, mitochondrial function, and autophagy-related genes. These data suggested that functional and structural changes resulted in impaired lipid metabolism, mitochondrial disorder, and unbalanced autophagy fluxes, caused by iron overload.
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Affiliation(s)
- Hye Eun Lee
- Neural Circuit Research Group, Korea Brain Research Institute, Daegu 41068, Korea; (H.E.L.); (M.K.J.); (S.G.N.)
| | - Min Kyo Jung
- Neural Circuit Research Group, Korea Brain Research Institute, Daegu 41068, Korea; (H.E.L.); (M.K.J.); (S.G.N.)
| | - Seul Gi Noh
- Neural Circuit Research Group, Korea Brain Research Institute, Daegu 41068, Korea; (H.E.L.); (M.K.J.); (S.G.N.)
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Korea
| | - Hye Bin Choi
- Neurovascular Unit Research Group, Korea Brain Research Institute, Daegu 41068, Korea;
| | - Se hyun Chae
- Neurovascular Unit Research Group, Korea Brain Research Institute, Daegu 41068, Korea;
- Correspondence: (S.h.C.); (J.Y.M.); Tel.: +82-53-980-8410 (J.Y.M.)
| | - Jae Hyeok Lee
- Department of Neurology, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan 50612, Korea;
- Medical Research Institute, Pusan National University School of Medicine, Yangsan 50612, Korea
| | - Ji Young Mun
- Neural Circuit Research Group, Korea Brain Research Institute, Daegu 41068, Korea; (H.E.L.); (M.K.J.); (S.G.N.)
- Correspondence: (S.h.C.); (J.Y.M.); Tel.: +82-53-980-8410 (J.Y.M.)
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Filosco F, Billone S, Collotta A, Timpanaro T, Tosto M, Falsaperla R, Marino S, Zanghì A, Praticò AD. WDR45 Gene and Its Role in Pediatric Epilepsies. JOURNAL OF PEDIATRIC NEUROLOGY 2021. [DOI: 10.1055/s-0041-1727174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
AbstractWD repeat domain 45 (WDR45) gene has been increasingly found in patients with developmental delay (DD) and epilepsy. Previously, WDR45 de novo mutations were reported in sporadic adult and pediatric patients presenting iron accumulation, while heterozygous mutations were associated with β-propeller protein-associated neurodegeneration (BPAN), a subtype of neurodegeneration with brain iron accumulation disorders, characterized by extrapyramidal movement disorders and abnormal accumulation of iron in the basal ganglia. Overall, people harboring WDR45 mutations have moderate to severe DD and different types of seizures. The phenotype of adult patients is characterized by extrapyramidal movement, dystonia, parkinsonism, language impairment, and involvement of the substantia nigra and in the globus pallidus at brain magnetic resonance imaging. Importantly, there are no findings of brain iron accumulation in brain in BPAN patients in the first decade of life, thus suggesting a progressive course of the disease. Comparatively, the main phenotype of pediatric patients is epilepsy with early onset, most of which present infantile spasms and arrest or regression of psychomotor development. The phenotype of patients with WDR45 mutations is variable, being different if caused by somatic mosaicism or germline mutations, and presenting with a different spectrum of manifestations in males and females. The treatment of affected individuals is symptomatic. Regarding the seizures, specific, gene-based approaches with specific antiepileptic drugs are not currently available. The early diagnosis of BPAN could be useful in some aspects, such as providing families a supportive treatment to their affected children.
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Affiliation(s)
- Federica Filosco
- Pediatrics Postgraduate Residency Program, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
| | - Sebastiano Billone
- Pediatrics Postgraduate Residency Program, University of Palermo, Palermo, Italy
| | - Ausilia Collotta
- Pediatrics Postgraduate Residency Program, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
| | - Tiziana Timpanaro
- Unit of Pediatric Endocrinology, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Monica Tosto
- Pediatrics Postgraduate Residency Program, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
| | - Raffaele Falsaperla
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
- Unit of Neonatal Intensive Care and Neonatology, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| | - Silvia Marino
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| | - Antonio Zanghì
- Department of Medical and Surgical Sciences and Advanced Technology “G.F. Ingrassia,” University of Catania, Catania, Italy
| | - Andrea D. Praticò
- Unit of Rare Diseases of the Nervous System in Childhood, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
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