[SCA6 presenting parkinsonism without ataxia--A case report]

Area of Science:

• Neurogenetics
• Neurology
• Molecular Medicine

Background:

• Parkinson disease (PD) is characterized by bradykinesia and typically responds to levodopa.
• Dopaminergic deficits in the nigrostriatal pathway are a hallmark of PD.

Observation:

• A 57-year-old man with bradykinesia showed poor levodopa response, atypical for PD.
• Brain imaging revealed cerebellar and cerebral atrophy, and reduced parietal lobe perfusion.
• Cardiac MIBG scintigraphy indicated reduced sympathetic innervation, and DAT imaging showed nigrostriatal damage.

Findings:

• Genetic testing identified spinocerebellar ataxia type 6 (SCA6) in the patient, his mother, and an uncle.
• The patient's presentation of parkinsonism without ataxia, linked to SCA6, is exceptionally rare.

Implications:

• This case highlights the phenotypic variability of SCA6, challenging typical diagnostic criteria.
• Understanding SCA6 with parkinsonism offers new insights into the pathogenesis of both ataxia and parkinsonian syndromes.
• Further research into SCA6 mechanisms may reveal novel therapeutic targets for neurodegenerative disorders.