Abstract
<strong>Background:</strong> Spinocerebellar ataxia (SCA) is an uncommon form of progressive cerebellar ataxia with multiple genetic causes and marked variability in phenotypic expression even across patients with identical genetic abnormalities. SCA27 is a recently identified SCA caused by mutations in the Fibroblast Growth Factor 14 gene, with a phenotypic expression that is only beginning to be fully appreciated. We report here a case of a 70-year-old male who presented with slowly worsening tremor and gait instability that began in his early adulthood along with additional features of parkinsonism on examination. Work-up revealed a novel pathogenic mutation in the Fibroblast Growth Factor 14 gene, and symptoms improved with amantadine and levodopa. We also provide a review of the literature in order to better characterize the phenotypic expression of this uncommon condition. <strong>Methods:</strong> Case report and review of the literature. <strong>Results:</strong> Review of the literature revealed a total of 32 previously reported clinical cases of SCA27. Including our case, we found that early-onset tremor (12.1 ± 10.5 years) was present in 95.8%, while gait ataxia tended to present later in life (23.7 ± 16.7 years) and was accompanied by limb ataxia, dysarthria, and nystagmus. Other features of SCA27 that may distinguish it from other SCAs include the potential for episodic ataxia, accompanying psychiatric symptoms, and cognitive impairment. <strong>Discussion:</strong> Testing for SCA27 should be considered in individuals with ataxia who report tremor as an initial or early symptom, as well as those with additional findings of episodic ataxia, neuropsychiatric symptoms, or parkinsonism.
Highlights
Spinocerebellar ataxia (SCA) is a growing collection of autosomal dominant cerebellar ataxias for which the underlying genetic etiologies are being increasingly identified
SCA27 is a slowly progressive, autosomal dominant cerebellar ataxia caused by a mutation in the Fibroblast GrowthFactor 14 (FGF14) gene
With the increased clinical information from the descriptions of 33 patients with SCA27 reported to date, we are better able to characterize the frequency of symptoms associated with this SCA and potentially improve our understanding of these symptoms
Summary
Spinocerebellar ataxia (SCA) is a growing collection of autosomal dominant cerebellar ataxias for which the underlying genetic etiologies are being increasingly identified. The patient was started on amantadine, which improved his head tremor and led to marked improvement in falls with reduced gait instability Three months later, he was started on one tablet of carbidopa/ levodopa 25/100 mg three times a day, which further improved his hand tremor (rest more than postural and action) and gait instability. At followup 18 months from initial presentation, the patient has remained on the same doses of medication and continues to report improvement in his head tremor and balance He does note that the tremor (rest, action, and postural) has worsened over time, but he denies any motor fluctuations related to the medications or dyskinesias and examination did not show any progression of other signs of parkinsonism
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