Case series: Downbeat nystagmus in SCA27B.
Case report
Downbeat nystagmus
FGF14
SCA27B
Journal
Journal of the neurological sciences
ISSN: 1878-5883
Titre abrégé: J Neurol Sci
Pays: Netherlands
ID NLM: 0375403
Informations de publication
Date de publication:
15 Nov 2023
15 Nov 2023
Historique:
received:
26
08
2023
revised:
16
10
2023
accepted:
22
10
2023
medline:
27
11
2023
pubmed:
1
11
2023
entrez:
31
10
2023
Statut:
ppublish
Résumé
Spinocerebellar ataxia (SCA) 27B, first reported in late 2022, is caused by the abnormal expansion of GAA repeats in the first intron of the FGF14 gene, which encodes the fibroblast growth factor 14. We present two late-onset cases, each manifesting mild cerebellar ataxia accompanied by omnidirectional downbeat nystagmus, which was enhanced in a suspended head position. None of the patients exhibited impaired head impulse or caloric tests. Repeat-primed PCR and targeted long-read nanopore sequence analysis of the FGF14 GAA repeat site identified more than 250 repeats, leading to the diagnosis of SCA27B. Downbeat nystagmus is reported to be associated with disturbances in the suppression of the vestibulo-ocular reflex (VOR). Our patients with SCA27B demonstrated downbeat nystagmus, likely due to a disruption of the VOR at the level of the cerebellar cortex, a potentially characteristic clinical feature of SCA27B. We have included video footages of eye movements recorded using Frenzel goggles for these cases. Omnidirectional downbeat nystagmus may be a distinctive clinical feature of SCA27B.
Sections du résumé
BACKGROUND
BACKGROUND
Spinocerebellar ataxia (SCA) 27B, first reported in late 2022, is caused by the abnormal expansion of GAA repeats in the first intron of the FGF14 gene, which encodes the fibroblast growth factor 14.
CASE PRESENTATION
METHODS
We present two late-onset cases, each manifesting mild cerebellar ataxia accompanied by omnidirectional downbeat nystagmus, which was enhanced in a suspended head position. None of the patients exhibited impaired head impulse or caloric tests. Repeat-primed PCR and targeted long-read nanopore sequence analysis of the FGF14 GAA repeat site identified more than 250 repeats, leading to the diagnosis of SCA27B.
DISCUSSION
CONCLUSIONS
Downbeat nystagmus is reported to be associated with disturbances in the suppression of the vestibulo-ocular reflex (VOR). Our patients with SCA27B demonstrated downbeat nystagmus, likely due to a disruption of the VOR at the level of the cerebellar cortex, a potentially characteristic clinical feature of SCA27B. We have included video footages of eye movements recorded using Frenzel goggles for these cases.
CONCLUSIONS
CONCLUSIONS
Omnidirectional downbeat nystagmus may be a distinctive clinical feature of SCA27B.
Identifiants
pubmed: 37907039
pii: S0022-510X(23)00310-6
doi: 10.1016/j.jns.2023.120849
pii:
doi:
Types de publication
Case Reports
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
120849Informations de copyright
Copyright © 2023. Published by Elsevier B.V.
Déclaration de conflit d'intérêts
Declaration of Competing Interest The authors report no relevant disclosures. Full disclosure from information provided by the authors is available with the full text of this article.