Pellerin, D;
Heindl, F;
Traschütz, A;
Rujescu, D;
Hartmann, AM;
Brais, B;
Houlden, H;
... Synofzik, M; + view all
(2024)
RFC1 repeat expansions in downbeat nystagmus syndromes: frequency and phenotypic profile.
Journal of Neurology
10.1007/s00415-024-12229-z.
(In press).
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Abstract
Objectives: The cause of downbeat nystagmus (DBN) remains unknown in a substantial number of patients (“idiopathic”), although intronic GAA expansions in FGF14 have recently been shown to account for almost 50% of yet idiopathic cases. Here, we hypothesized that biallelic RFC1 expansions may also represent a recurrent cause of DBN syndrome. Methods: We genotyped the RFC1 repeat and performed in-depth phenotyping in 203 patients with DBN, including 65 patients with idiopathic DBN, 102 patients carrying an FGF14 GAA expansion, and 36 patients with presumed secondary DBN. Results: Biallelic RFC1 AAGGG expansions were identified in 15/65 patients with idiopathic DBN (23%). None of the 102 GAA-FGF14-positive patients, but 2/36 (6%) of patients with presumed secondary DBN carried biallelic RFC1 expansions. The DBN syndrome in RFC1-positive patients was characterized by additional cerebellar impairment in 100% (15/15), bilateral vestibulopathy (BVP) in 100% (15/15), and polyneuropathy in 80% (12/15) of cases. Compared to GAA-FGF14-positive and genetically unexplained patients, RFC1-positive patients had significantly more frequent neuropathic features on examination and BVP. Furthermore, vestibular function, as measured by the video head impulse test, was significantly more impaired in RFC1-positive patients. Discussion: Biallelic RFC1 expansions are a common monogenic cause of DBN syndrome.
| Type: | Article |
|---|---|
| Title: | RFC1 repeat expansions in downbeat nystagmus syndromes: frequency and phenotypic profile |
| Location: | Germany |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1007/s00415-024-12229-z |
| Publisher version: | http://dx.doi.org/10.1007/s00415-024-12229-z |
| Language: | English |
| Additional information: | Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. |
| Keywords: | Bilateral vestibulopathy, CANVAS, Cerebellar ataxia, FGF14, GAA-FGF14 ataxia, SCA27B |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology > Department of Neuromuscular Diseases |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10188924 |
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