Spinocerebellar ataxia with mixed tremor and hippocampal atrophy: case report and literature review

Objective This study aimed to investigate the clinical features of spinocerebellar ataxia 12 (SCA12). Methods Sanger sequencing-based genetic testing was performed on a patient initially diagnosed with essential tremor. Results The patient exhibited an abnormal expansion of 69 cytosine-adenine-guanine (CAG) repeats, confirming the diagnosis of SCA12. Conclusion SCA12 may present with mixed tremor, predominantly postural/kinetic tremor with a superimposed resting component and hippocampal atrophy. However, the direct association between hippocampal atrophy and SCA12 pathology remains unclear and may reflect concomitant age-related or vascular changes. Furthermore, PPP2R2B gene abnormalities may also affect the synergistic function of the basal ganglia-thalamocortical and cerebello-thalamocortical circuits.