Objective: To give a concise description of clinical and imaging features of spinocerebellar ataxia type 14 (SCA14).

Background: Since its genetic definition in 2003, the very rare SCA14 is increasingly recognized among patients with hitherto undefined spinocerebellar ataxia in Germany.

Methods: Patients were enrolled in a coordinated study at two German university ataxia clinics and underwent structured medical history, clinical examination (SARA, INAS, SCAFI) and comprehensive neuropsychological testing. Nerve conduction was studied in a subset. MRI were rated by one experienced neuroradiologist.

Results: We studied 19 individuals (12 F, age 53±13y, no family history in 3) of 14 families, all with different mutations in exons 1 to 5 of the PRKCG gene. Onset of permanent gait ataxia – presenting symptom in all but three – varied between 4 and 50 years (mean±SD 38±15y). Five subjects reported minor or episodic motor difficulty of gait or speech already present in childhood. SARA scores of 10.5±3.8 at a disease duration of 21.3±12.6y indicated slow progression. INAS median of 2 (range 0-6) indicated mild extra-cerebellar involvement. This included sensorimotor involvement (9), urinary symptoms (7), dystonia (3), myoclonus (3) or cognitive symptoms (2), all of mild expression. On neuropsychological testing, attention and visuoconstruction was compromised compared to matched healthy subjects. Electrophysiology was normal in 7 while signs of mild axonal or mixed neuropathy were seen in 7. Mild to moderate atrophy confined to the cerebellar anterior lobe and vermis with additional mildly hyperintense cerebellar white matter was seen in all patients. None featured hyperintensity of the middle cerebellar peduncle or atrophy of pons or cerebral cortex, while additional atrophy of the superior cerebellar peduncle was seen in two.

Conclusions: We here present data of a coordinated study in the largest reported sample of SCA14. Clinical and imaging data confirm previous descriptions of SCA14 as a rather slowly progressive and purely cerebellar disorder. Mild sensorimotor or urinary symptoms, dystonia and myoclonus were noted as additional symptoms. Remarkably, some subjects reported symptoms of childhood onset that turned into a progressive course later on. No genotype-related differences in phenotype became apparent. In one subject with action-induced myoclonus, marked improvement was seen with valproate.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/clinical-and-imaging-characteristics-of-spinocerebellar-ataxia-type-14-defined-in-a-german-multi-center-sample/