Isolated palatal tremor as unique clinical manifestation of SCA 18 due to a new mutation of IFRD1
Echeveste B (1), Covarrubias E (2), Cabello JP (3), Luquin MR (4)
(1) Neurology Department, Clínica Universidad de Navarra, Pamplona, Spain.
(2) Neurology Department, Clínica Universidad de Navarra, Pamplona, Spain.
(3) Neurology Department, Clínica Universidad de Navarra, Madrid, Spain.
(4) Neurology Department, Clínica Universidad de Navarra, Pamplona, Spain.
A 62-year old man was seen at the Department of Neurology of the University of Navarra Clinic because of speech difficulties, marked by a tremulous voice. He did not report other symptoms such as ear-clicking, ocular myoclonus or gait instability.
He had been treated with different drugs for bipolar disorder, and his speaking impairment was considered a drug-induced side effect. There was no family history of tremor, ataxia or other neurological diseases. At physical examination, a palatal tremor and a trembling voice were noted (Video 1).
The rest of the neurological examination, including gait, was normal. Brain MRI (3 T) was performed and a high intensity signal of the inferior olive and cerebellar atrophy in the T2 FLAIR sequence was observed (Fig. 1). Genetic study for ataxias (199-gene panel) including the more common gene mutations associated with cerebellar disorders was performed.
We found a novel and possibly pathogenic mutation in the IFRD1 gene [c.4C>G(p.Pro2Ala)]. Interestingly, mutations in this gene have been associated with SCA 18.
The patient was treated with botulinum toxin injections in the tensor veli palatine muscle with a marked improvement of palatal tremor and tremulous voice without serious side effects.
CITATION Parkinsonism Relat Disord. 2017 Sep;42:100-101. doi: 10.1016/j.parkreldis.2017.05.026.