{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,22]],"date-time":"2026-10-22T16:52:58Z","timestamp":1792687978306,"version":"4.5.0"},"reference-count":46,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2025,7,22]],"date-time":"2025-07-22T00:00:00Z","timestamp":1753142400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Neurol."],"abstract":"<jats:sec><jats:title>Introduction<\/jats:title><jats:p>The genetic etiology of Parkinson\u2019s disease (PD) is complex; approximately 10% of patients with PD have various gene mutations that lead to familial forms of the disease. Recent analyses of non-coding repeat regions revealed that many neurodegenerative diseases are associated with pathological expansions. We evaluated the genetic background of non-coding repeat expansions in Japanese patients with PD.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>We collected blood samples from 203 Japanese patients with PD and analyzed various non-coding repeat genes, including <jats:italic>ATXN8OS, RFC1, C9ORF72<\/jats:italic>, <jats:italic>NOTCH2NLC, BEAN1\/TK2,<\/jats:italic> and <jats:italic>NOP56<\/jats:italic>, using PCR-Sanger sequencing, repeat-primed PCR assay, and long-read sequencing.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Three patients with PD (1.5%) were found to have heterozygous repeat expansions in <jats:italic>ATXN8OS,<\/jats:italic> the gene causative of spinocerebellar ataxia type 8 and is associated with long non-coding RNA. One (0.5%) patient had compound heterozygous repeat expansions (AAGGG and ACAGG) in <jats:italic>RFC1<\/jats:italic>, the gene causative of cerebellar ataxia, neuropathy, and vestibular areflexia syndrome, which encodes a DNA repair protein. No patient had repeat expansions in <jats:italic>C9ORF72, NOTCH2NLC, BEAN1\/TK2,<\/jats:italic> or <jats:italic>NOP56<\/jats:italic>. All patients with <jats:italic>ATXN8OS<\/jats:italic> repeat expansions exhibited typical parkinsonism with relatively rare subjective dysphagia, which was confirmed by videofluoroscopic results. Functional imaging, such as dopamine-transporter single photon emission computed tomography, showed abnormal findings in patients with non-coding repeat expansions.<\/jats:p><\/jats:sec><jats:sec><jats:title>Discussion<\/jats:title><jats:p>Our findings revealed the importance of non-coding repeat expansions in Japanese patients with PD. This is the first study to show the positive result of non-coding repeat expansions in many patients with PD in Japan.<\/jats:p><\/jats:sec>","DOI":"10.3389\/fneur.2025.1606305","type":"journal-article","created":{"date-parts":[[2025,7,22]],"date-time":"2025-07-22T04:10:31Z","timestamp":1753157431000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":2,"title":["Non-coding repeat analyses in patients with Parkinson\u2019s 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