PSP-Phenotype in SCA8: Case Report and Systemic Review
Spinocerebellar ataxia type 8 (SCA8) is a rare autosomal dominant neurodegenerative disease caused by expanded CTA/CTG repeats in the ATXN8OS gene. Many patients had pure cerebellar ataxia, while some had parkinsonism, both without causal explanation. We analyzed the ATXN8OS gene in 150 Japanese patients with ataxia and 76 patients with Parkinson’s disease or related disorders. We systematically reassessed 123 patients with SCA8, both our patients and those reported in other studies. Two patients with progressive supranuclear palsy (PSP) had mutations in the ATXN8OS gene. Systematic analyses revealed that patients with parkinsonism had significantly shorter CTA/CTG repeat expansions and older age at onset than those with predominant ataxia. We show the imaging results of patients with and without parkinsonism. We also found a significant inverse relationship between repeat sizes and age at onset in all patients, which has not been detected previously. Our results may be useful to genetic counseling, improve understanding of the pathomechanism, and extend the clinical phenotype of SCA8.
KeywordsSpinocerebellar ataxia type 8 CTA/CTG repeats Triplet repeat Intermediate expansion Parkinsonism
The authors thank Dr. Abe of the Department of Neurology, Okayama University, for technical assistance in the analysis of the NOP56 gene causative for SCA36.
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
1. Design or conceptualization of the study.
2. Acquisition of the data.
3. Analysis or interpretation of the data.
4. Drafting or revising the manuscript for intellectual content.
Dr. Makoto Samukawa has contributed to 1, 2, and 3.
Dr. Makito Hirano has contributed to 2, 3, and 4.
Dr. Kazumasa Saigoh has contributed to 2, 3, and 4.
Dr. Shigeru Kawai has contributed to 2, 3, and 4.
Dr. Yukihiro Hamada has contributed to 2, 3, and 4.
Dr. Daisuke Takahashi has contributed to 2, 3, and 4.
Dr. Yusaku Nakamura has contributed to 1, 3, and 4.
Dr. Susumu Kusunoki has contributed to 1, 3, and 4.
Compliance with Ethical Standards
Conflict of Interest
None of the authors have any conflict of interest, including financial, personal, or other relationships with other people or organizations within 3 years since beginning the work submitted that could inappropriately influence (bias) our work.
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