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Ishikawa K. Spinocerebellar ataxia type 31 (SCA31). J Hum Genet 2023; 68:153-156. [PMID: 36319738 PMCID: PMC9968654 DOI: 10.1038/s10038-022-01091-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 09/22/2022] [Accepted: 10/03/2022] [Indexed: 02/28/2023]
Abstract
Spinocerebellar ataxia type 31 (SCA31) is one of the most common forms of autosomal-dominant cerebellar ataxia in Japan. SCA31 has a strong founder effect, which is consistent with the fact that this disease is basically absent in other ethnicities. After searching the entire founder region of a 2-megabase (Mb), we finally identified a 2.5 to 3.8 kb-long complex penta-nucleotide repeat containing (TGGAA)n, (TAGAA)n, (TAAAA)n and (TAAAATAGAA)n as the only genetic change segregating SCA31 individuals from normal people. Furthermore, (TGGAA)n was isolated as the only repeat explaining the pathogenesis because other repeats were encountered in control Japanese. From the genomic point of view, the complex penta-nucleotide repeat lies in an intronic segment shared by two genes, BEAN1 (brain expressed, associated with Nedd4) and TK2 (thymidine kinase 2) transcribed in mutually opposite directions. While TK2 is ubiquitously expressed, BEAN1 is transcribed only in the brain. Thus, the complex repeat is bi-directionally transcribed exclusively in the brain, as two independent non-coding repeats. Furthermore, the complex repeat containing (UGGAA)n was found to form abnormal RNA structures, called RNA foci, in cerebellar Purkinje cell nuclei of SCA31 patients' brains. Subsequent investigation by over-expressing (UGGAA)n in Drosophila revealed that the RNA containing (UGGAA)n exerts toxicity in a length- and expression level-dependent manner, whereas its toxicity could be dampened by (UGGAA)n-binding proteins, TDP-43, FUS and hnRNP A2/B1. It seems rational to formulate a treatment strategy through enhancing the role of RNA-binding proteins against (UGGAA)n-toxicity in SCA31.
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Affiliation(s)
- Kinya Ishikawa
- The Center for Personalized Medicine for Healthy Aging, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan.
- Department of Neurology and Neurological Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan.
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Saucier J, Al-Qadi M, Amor MB, Ishikawa K, Chamard-Witkowski L. Spinocerebellar ataxia type 31: A clinical and radiological literature review. J Neurol Sci 2023; 444:120527. [PMID: 36563608 DOI: 10.1016/j.jns.2022.120527] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 12/06/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022]
Abstract
Spinocerebellar ataxia type 31 (SCA31) is an autosomal dominant disease, classified amongst pure cerebellar ataxias (ADCA type 3). While SCA31 is the third most prevalent autosomal dominant ataxia in Japan, it is extremely rare in other countries. A literature review was conducted on PubMed, where we included all case reports and studies describing the clinical presentation of original SCA31 cases. The clinical and radiological features of 374 patients issued from 25 studies were collected. This review revealed that the average age of onset was 59.1 ± 3.3 years, with symptoms of slowly progressing ataxia and dysarthria. Other common clinical features were oculomotor dysfunction (38.8%), dysphagia (22.1%), hypoacousia (23.3%), vibratory hypoesthesia (24.3%), and dysreflexia (41.6%). Unfrequently, abnormal movements (7.4%), extrapyramidal symptoms (4.5%) and cognitive impairment (6.9%) may be observed. Upon radiological examination, clinicians can expect a high prevalence of cerebellar atrophy (78.7%), occasionally accompanied by brainstem (9.1%) and cortical (9.1%) atrophy. Although SCA31 is described as a slowly progressive pure cerebellar syndrome characterized by cerebellar signs such as ataxia, dysarthria and oculomotor dysfunction, this study evaluated a high prevalence of extracerebellar manifestations. Extracerebellar signs were observed in 52.5% of patients, primarily consisting of dysreflexia, vibratory hypoesthesia and hypoacousia. Nonetheless, we must consider the old age and longstanding disease course of patients as a confounding factor for extracerebellar sign development, as some may not be directly attributable to SCA31. Clinicians should consider SCA31 in patients with a hereditary, pure cerebellar syndrome and in patients with extracerebellar signs.
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Affiliation(s)
- Jacob Saucier
- Centre de formation médicale du Nouveau-Brunswick, Université de Sherbrooke, Moncton, NB, Canada..
| | - Mohammad Al-Qadi
- Centre de formation médicale du Nouveau-Brunswick, Université de Sherbrooke, Moncton, NB, Canada
| | - Mouna Ben Amor
- Centre de formation médicale du Nouveau-Brunswick, Université de Sherbrooke, Moncton, NB, Canada.; Department of Genetic Medicine, Dr. Georges-L.-Dumont University Hospital Centre, Moncton, NB, Canada
| | - Kinya Ishikawa
- The Center for Personalized Medecine for Healthy Aging, Tokyo, Japan; Department of Neurology and Neurological Science, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, 113-8519 Tokyo, Japan
| | - Ludivine Chamard-Witkowski
- Centre de formation médicale du Nouveau-Brunswick, Université de Sherbrooke, Moncton, NB, Canada.; Department of Neurology, Dr. Georges-L.-Dumont University Hospital Centre, Moncton, NB, Canada
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Mechanistic and Therapeutic Insights into Ataxic Disorders with Pentanucleotide Expansions. Cells 2022; 11:cells11091567. [PMID: 35563872 PMCID: PMC9099484 DOI: 10.3390/cells11091567] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 05/02/2022] [Accepted: 05/05/2022] [Indexed: 02/01/2023] Open
Abstract
Pentanucleotide expansion diseases constitute a special class of neurodegeneration. The repeat expansions occur in non-coding regions, have likely arisen from Alu elements, and often result in autosomal dominant or recessive phenotypes with underlying cerebellar neuropathology. When transcribed (potentially bidirectionally), the expanded RNA forms complex secondary and tertiary structures that can give rise to RNA-mediated toxicity, including protein sequestration, pentapeptide synthesis, and mRNA dysregulation. Since several of these diseases have recently been discovered, our understanding of their pathological mechanisms is limited, and their therapeutic interventions underexplored. This review aims to highlight new in vitro and in vivo insights into these incurable diseases.
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Ishiguro T, Nagai Y, Ishikawa K. Insight Into Spinocerebellar Ataxia Type 31 (SCA31) From Drosophila Model. Front Neurosci 2021; 15:648133. [PMID: 34113230 PMCID: PMC8185138 DOI: 10.3389/fnins.2021.648133] [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: 12/31/2020] [Accepted: 03/31/2021] [Indexed: 11/13/2022] Open
Abstract
Spinocerebellar ataxia type 31 (SCA31) is a progressive neurodegenerative disease characterized by degeneration of Purkinje cells in the cerebellum. Its genetic cause is a 2.5- to 3.8-kb-long complex pentanucleotide repeat insertion containing (TGGAA)n, (TAGAA)n, (TAAAA)n, and (TAAAATAGAA)n located in an intron shared by two different genes: brain expressed associated with NEDD4-1 (BEAN1) and thymidine kinase 2 (TK2). Among these repeat sequences, (TGGAA)n repeat was the only sequence segregating with SCA31, which strongly suggests its pathogenicity. In SCA31 patient brains, the mutant BEAN1 transcript containing expanded UGGAA repeats (UGGAAexp) was found to form abnormal RNA structures called RNA foci in cerebellar Purkinje cell nuclei. In addition, the deposition of pentapeptide repeat (PPR) proteins, poly(Trp-Asn-Gly-Met-Glu), translated from UGGAAexp RNA, was detected in the cytoplasm of Purkinje cells. To uncover the pathogenesis of UGGAAexp in SCA31, we generated Drosophila models of SCA31 expressing UGGAAexp RNA. The toxicity of UGGAAexp depended on its length and expression level, which was accompanied by the accumulation of RNA foci and translation of repeat-associated PPR proteins in Drosophila, consistent with the observation in SCA31 patient brains. We also revealed that TDP-43, FUS, and hnRNPA2B1, motor neuron disease–linked RNA-binding proteins bound to UGGAAexp RNA, act as RNA chaperones to regulate the formation of RNA foci and repeat-associated translation. Further research on the role of RNA-binding proteins as RNA chaperones may also provide a novel therapeutic strategy for other microsatellite repeat expansion diseases besides SCA31.
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Affiliation(s)
- Taro Ishiguro
- Department of Neurology and Neurological Science, Tokyo Medical and Dental University, Bunkyo City, Japan
| | - Yoshitaka Nagai
- Department of Neurotherapeutics, Osaka University Graduate School of Medicine, Suita, Japan
| | - Kinya Ishikawa
- Department of Neurology and Neurological Science, Tokyo Medical and Dental University, Bunkyo City, Japan.,Department of Personalized Genomic Medicine for Health, Graduate School, Tokyo Medical and Dental University, Bunkyo City, Japan
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Ishikawa K, Nagai Y. Molecular Mechanisms and Future Therapeutics for Spinocerebellar Ataxia Type 31 (SCA31). Neurotherapeutics 2019; 16:1106-1114. [PMID: 31755042 PMCID: PMC6985187 DOI: 10.1007/s13311-019-00804-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Spinocerebellar ataxia type 31 (SCA31) is one of the autosomal-dominant neurodegenerative disorders that shows progressive cerebellar ataxia as a cardinal symptom. This disease is caused by a 2.5- to 3.8-kb-long complex pentanucleotide repeat containing (TGGAA)n, (TAGAA)n, (TAAAA)n, and (TAAAATAGAA)n in an intron of the gene called BEAN1 (brain expressed, associated with Nedd4). By comparing various pentanucleotide repeats in this particular locus among control Japanese and Caucasian populations, it was found that (TGGAA)n was the only sequence segregating with SCA31, strongly suggesting the pathogenicity of (TGGAA)n. The complex repeat also lies in an intron of another gene, TK2 (thymidine kinase 2), which is transcribed in the opposite direction, indicating that the complex repeat is bi-directionally transcribed as noncoding repeats. In SCA31 human brains, (UGGAA)n, the BEAN1 transcript of SCA31 mutation was found to form abnormal RNA structures called RNA foci in cerebellar Purkinje cell nuclei. Subsequent RNA pulldown analysis disclosed that (UGGAA)n binds to RNA-binding proteins TDP-43, FUS, and hnRNP A2/B1. In fact, TDP-43 was found to co-localize with RNA foci in human SCA31 Purkinje cells. To dissect the pathogenesis of (UGGAA)n in SCA31, we generated transgenic fly models of SCA31 by overexpressing SCA31 complex pentanucleotide repeats in Drosophila. We found that the toxicity of (UGGAA)n is length- and expression level-dependent, and it was dampened by co-expressing TDP-43, FUS, and hnRNP A2/B1. Further investigation revealed that TDP-43 ameliorates (UGGAA)n toxicity by directly fixing the abnormal structure of (UGGAA)n. This led us to propose that TDP-43 acts as an RNA chaperone against toxic (UGGAA)n. Further research on the role of RNA-binding proteins as RNA chaperones may provide a novel therapeutic strategy for SCA31.
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Affiliation(s)
- Kinya Ishikawa
- Department of Neurology and Neurological Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
- The Center for Personalized Medicine for Healthy Aging, Tokyo Medical and Dental University, Tokyo, Japan.
| | - Yoshitaka Nagai
- Department of Neurotherapeutics, Osaka University Graduate School of Medicine, Osaka, Japan
- Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Japan
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Sun YM, Lu C, Wu ZY. Spinocerebellar ataxia: relationship between phenotype and genotype - a review. Clin Genet 2016; 90:305-14. [PMID: 27220866 DOI: 10.1111/cge.12808] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Revised: 05/16/2016] [Accepted: 05/16/2016] [Indexed: 12/12/2022]
Abstract
Spinocerebellar ataxia (SCA) comprises a large group of heterogeneous neurodegenerative disorders inherited in an autosomal dominant fashion. It is characterized by progressive cerebellar ataxia with oculomotor dysfunction, dysarthria, pyramidal signs, extrapyramidal signs, pigmentary retinopathy, peripheral neuropathy, cognitive impairment and other symptoms. It is classified according to the clinical manifestations or genetic nosology. To date, 40 SCAs have been characterized, and include SCA1-40. The pathogenic genes of 28 SCAs were identified. In recent years, with the widespread clinical use of next-generation sequencing, the genes underlying SCAs, and the mutants as well as the affected phenotypes were identified. These advances elucidated the phenotype-genotype relationship in SCAs. We reviewed the recent clinical advances, genetic features and phenotype-genotype correlations involving each SCA and its differentiation. The heterogeneity of the disease and the genetic diagnosis might be attributed to the regional distribution and clinical characteristics. Therefore, recognition of the phenotype-genotype relationship facilitates genetic testing, prognosis and monitoring of symptoms.
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Affiliation(s)
- Y-M Sun
- Department of Neurology and Institute of Neurology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - C Lu
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, the Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou, China
| | - Z-Y Wu
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, the Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, China. .,Joint Institute for Genetics and Genome Medicine between Zhejiang University and University of Toronto, Zhejiang University, Hangzhou, China.
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Pedroso JL, Abrahao A, Ishikawa K, Raskin S, de Souza PVS, de Rezende Pinto WBV, Braga-Neto P, de Albuquerque MVC, Mizusawa H, Barsottini OG. When should we test patients with familial ataxias for SCA31? A misdiagnosed condition outside Japan? J Neurol Sci 2015; 355:206-8. [DOI: 10.1016/j.jns.2015.05.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 04/28/2015] [Accepted: 05/12/2015] [Indexed: 10/23/2022]
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Ikeda Y, Nagai M, Kurata T, Yamashita T, Ohta Y, Nagotani S, Deguchi K, Takehisa Y, Shiro Y, Matsuura T, Abe K. Comparisons of acoustic function in SCA31 and other forms of ataxias. Neurol Res 2012; 33:427-32. [PMID: 21535943 DOI: 10.1179/1743132810y.0000000011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVE To investigate whether acoustic impairment can be one of the characteristic extracerebellar symptoms in sporadic and hereditary ataxias including spinocerebellar ataxia type 31 (SCA31). METHODS We investigated genotypes of dominant ataxia families, and determined a frequency of each form in our cohort of 154 families. Acoustic function in the groups of various forms of ataxia with multiple system atrophy of cerebellar predominance (MSA-C), cortical cerebellar atrophy (CCA), and hereditary ataxias including SCA31 was evaluated by using audiogram and brainstem auditory evoked potentials (BAEPs). RESULTS Genetic analysis of dominant ataxia families revealed that a frequency of SCA31 in our cohort was fewer than that reported from other areas of Japan, indicating that SCA31 is not widely distributed throughout Japan. Results of audiogram showed no significant difference of hearing levels among ataxic groups, and those of BAEPs did not support inner ear dysfunction in SCA31 in which hearing loss had initially been suggested as one of its characteristic symptoms. CONCLUSION This study suggests that acoustic impairment is neither specific to SCA31, MSA-C and CCA nor useful in making a differential diagnosis among them.
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Affiliation(s)
- Yoshio Ikeda
- Department of Neurology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Japan.
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Ouyang Y, He Z, Li L, Qin X, Zhao Y, Yuan L. Spinocerebellar ataxia type 31 exists in northeast China. J Neurol Sci 2012; 316:164-7. [PMID: 22353852 DOI: 10.1016/j.jns.2012.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 01/30/2012] [Accepted: 02/01/2012] [Indexed: 10/28/2022]
Abstract
Spinocerebellar ataxia type 31 (SCA31), is a recently defined subtype of autosomal dominant cerebellar ataxia (ADCA) characterized by late-onset pure cerebellar ataxia. SCA31 is common in Japan but whether or not it exists in other countries is still unclear. In this study, the authors describe a sporadic Chinese patient with SCA31. Although the cardinal clinical features, i.e., late-onset cerebellar ataxia and hearing impairment in our sporadic patient were similar to those described previously in Japan, mild axonal sensorimotor neuropathy was identified in our SCA31 patient, which is somewhat distinct from most prior reports of the disease. This is the first report of SCA31 in China; thus, extending the ethnic association beyond families of Japanese origin. In addition, our study suggests that the clinical features of SCA31 might be broader than previously thought.
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Affiliation(s)
- Yi Ouyang
- Department of Neurology, First Affiliated Hospital, China Medical University, Shenyang 110001, Liaoning Province, China
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Mehta P, Fernando MMA, Pickering MC, Wilson Y, Molloy S, Colaco CB. Lateral medullary syndrome with anti-neuronal antibodies (anti-Ta/Ma2) in primary Sjogren's syndrome. Rheumatology (Oxford) 2009; 48:1174-6. [DOI: 10.1093/rheumatology/kep210] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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