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Lam T, Rocca C, Ibanez K, Dalmia A, Tallman S, Hadjivassiliou M, Hensiek A, Nemeth A, Facchini S, Wood N, Cortese A, Houlden H, Tucci A. Repeat expansions in NOP56 are a cause of spinocerebellar ataxia Type 36 in the British population. Brain Commun 2023; 5:fcad244. [PMID: 37810464 PMCID: PMC10558097 DOI: 10.1093/braincomms/fcad244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 07/11/2023] [Accepted: 09/12/2023] [Indexed: 10/10/2023] Open
Abstract
Spinocerebellar ataxias form a clinically and genetically heterogeneous group of neurodegenerative disorders characterized by progressive cerebellar ataxia. Their prevalence varies among populations and ethnicities. Spinocerebellar ataxia 36 is caused by a GGCCTG repeat expansion in the first intron of the NOP56 gene and is characterized by late-onset ataxia, sensorineural hearing loss and upper and lower motor neuron signs, including tongue fasciculations. Spinocerebellar ataxia 36 has been described mainly in East Asian and Western European patients and was thought to be absent in the British population. Leveraging novel bioinformatic tools to detect repeat expansions from whole-genome sequencing, we analyse the NOP56 repeat in 1257 British patients with hereditary ataxia and in 7506 unrelated controls. We identify pathogenic repeat expansions in five families (seven patients), representing the first cohort of White British descent patients with spinocerebellar ataxia 36. Employing in silico approaches using whole-genome sequencing data, we found an 87 kb shared haplotype in among the affected individuals from five families around the NOP56 repeat region, although this block was also shared between several controls, suggesting that the repeat arises on a permissive haplotype. Clinically, the patients presented with slowly progressive cerebellar ataxia with a low rate of hearing loss and variable rates of motor neuron impairment. Our findings show that the NOP56 expansion causes ataxia in the British population and that spinocerebellar ataxia 36 can be suspected in patients with a late-onset, slowly progressive ataxia, even without the findings of hearing loss and tongue fasciculation.
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Affiliation(s)
- Tanya Lam
- Department of Clinical Genetics, Great Ormond Street Hospital NHS Trust, London, WC1N 3JH, UK
| | - Clarissa Rocca
- Clinical Pharmacology, William Harvey Research Institute, School of Medicine and Dentistry, Queen Mary University of London, London, EC1M 6BQ, UK
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, WC1N 3BG, UK
| | - Kristina Ibanez
- Clinical Pharmacology, William Harvey Research Institute, School of Medicine and Dentistry, Queen Mary University of London, London, EC1M 6BQ, UK
| | - Anupriya Dalmia
- Clinical Pharmacology, William Harvey Research Institute, School of Medicine and Dentistry, Queen Mary University of London, London, EC1M 6BQ, UK
| | | | - Marios Hadjivassiliou
- Academic Department of Neurosciences and Neuroradiology, Sheffield Teaching Hospitals NHS Trust, Sheffield, S10 2JF, UK
| | - Anke Hensiek
- Department of Clinical Neurosciences, Addenbrookes Hospital, Cambridge, CB2 0QQ, UK
| | - Andrea Nemeth
- Oxford Centre for Genomic Medicine, Oxford University Hospitals National Health Service Foundation Trust, Oxford, OX3 9DU, UK
| | - Stefano Facchini
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, WC1N 3BG, UK
| | - Nicholas Wood
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, WC1N 3BG, UK
| | - Andrea Cortese
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, WC1N 3BG, UK
- Department of Brain and Behavioural Sciences, University of Pavia, Pavia, 27100, Italy
| | - Henry Houlden
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, WC1N 3BG, UK
| | - Arianna Tucci
- Clinical Pharmacology, William Harvey Research Institute, School of Medicine and Dentistry, Queen Mary University of London, London, EC1M 6BQ, UK
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Han F, Su D, Qu C. Spinocerebellar ataxia type 40: A case report and literature review. Transl Neurosci 2021; 12:379-384. [PMID: 34721893 PMCID: PMC8525662 DOI: 10.1515/tnsci-2020-0190] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 09/05/2021] [Accepted: 09/22/2021] [Indexed: 12/22/2022] Open
Abstract
Spinocerebellar ataxias (SCAs) are a group of neurodegenerative diseases with ataxia as the main clinical manifestation. The phenotypes, gene mutations, and involved sites of different subtypes show a high degree of heterogeneity. The incidence of SCA varies greatly among different subtypes and the case of SCA40 is extremely rare. The aim of this study is to report a rare case of SCA40 and systematically review the incidence, gene mutation, and phenotype of SCAs, especially SCA40.
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Affiliation(s)
- Fengyue Han
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250100, China
| | - Dan Su
- Department of Neurology, Jinan Shizhong District People's Hospital, Jinan, Shandong, 250100, China
| | - Chuanqiang Qu
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250100, China
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Tan EC, Lai PS. Molecular diagnosis of neurogenetic disorders involving trinucleotide repeat expansions. Expert Rev Mol Diagn 2014; 5:101-9. [PMID: 15723596 DOI: 10.1586/14737159.5.1.101] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
There are more than 15 known neurogenetic disorders involving trinucleotide repeat expansion. Expanded repeats range from small expansions of 20-100 copies to larger expansions of up to several thousand units. These dynamic expansions result in variability in age of onset, degree of severity and clinical presentation. Individuals carrying alleles in the intermediate range, known as premutation alleles, are often asymptomatic, but can potentially transmit a further expanded allele to his/her offspring. For autosomal dominant adult-onset disorders, carriers are asymptomatic prior to disease onset. With current molecular tools, it is now possible to determine the presence and number of expanded repeats for accurate diagnosis, presymptomatic testing and carrier status screening. This review examines some of the current approaches for molecular diagnosis and discusses the issues unique to triplet repeat diseases.
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Affiliation(s)
- Ene-Choo Tan
- DSO National Laboratories, Population Genetics Programme, Defence Medical and Environmental Research Institute, 27 Medical Drive, 117510 Singapore.
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Abstract
Chorea is one of the major types of involuntary movement disorders originating from dysfunctional neuronal networks interconnecting the basal ganglia and frontal cortical motor areas. The syndrome is characterised by a continuous flow of random, brief, involuntary muscle contractions and can result from a wide variety of causes. Diagnostic work-up can be straightforward in patients with a positive family history of Huntington's disease or acute-onset hemichorea in patients with lacunar stroke, but it can be a challenging and complex task in rare autoimmune or genetic choreas. Principles of management focus on establishing an aetiological classification and, if possible, removal of the cause. Preventive strategies may be possible in Huntington's disease where genetic counselling plays a major part. In this review we summarise the current understanding of the neuroanatomy and pathophysiology of chorea, its major aetiological classes, and principles of diagnostic work-up and management.
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Lim SW, Zhao Y, Chua E, Law HY, Yuen Y, Pavanni R, Wong MC, Ng IS, Yoon CS, Puong KY, Lim SH, Tan EK. Genetic analysis of SCA2, 3 and 17 in idiopathic Parkinson's disease. Neurosci Lett 2006; 403:11-4. [PMID: 16687213 DOI: 10.1016/j.neulet.2006.04.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2006] [Revised: 03/31/2006] [Accepted: 04/14/2006] [Indexed: 10/24/2022]
Abstract
Recent reports of SCA2 and SCA3 patients who presented with levodopa responsive parkinsonism have generated considerable interest as they have implications for genetic testing. It is unclear whether ethnic race alone or founder effects within certain geographical region explain such an association. In this study, we conducted genetic analysis of SCA2, 3, 17 in an ethnic Chinese cohort with early onset and familial Parkinson's disease (PD) and healthy controls. A total of 191 subjects comprising of 91 PD and 100 healthy controls were examined. We identified one positive case of SCA2 in an early-onset sporadic PD patient who had CAG 36 repeats, yielding a prevalence of 2.2% in early-onset sporadic PD patients and less than 1.0% in our study PD population. The size of the repeats was lower than the expanded repeats (38-57) in SCA2 patients with ataxia in our population. All the children of the patient were physically normal even though some of them carried the repeat expansion of similar size. No cases and controls were positive for SCA3 and SCA17. We do not think routine screening of SCA2, SCA3 and SCA17 for all idiopathic PD patients is cost-effective in our ethnic Chinese population. However, SCA2 should be a differential diagnosis in young onset sporadic PD when genetic mutations of other known PD genes have been excluded.
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Affiliation(s)
- S W Lim
- Department of Neurology, Singapore General Hospital, Outram Road, Singapore 169608, Singapore
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Tan EK. Re-defining Neurological Syndromes: The Genotype Meets the Phenotype. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 2006. [DOI: 10.47102/annals-acadmedsg.v35n2p63] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
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