Diagnosis:
Clinical features plus imaging
Clinical features:
2-10 years, Progressive ataxia & dementia
Truncal ataxia, dysesthesia and hyporeflexia of the lower legs, and mild dysarthria
Supranuclear gaze palsy
Pyramidal signs
Pathology:
Amyloid plaques: PrP positive
Minimal spongiform (vacuolar) change
PRNP gene (GSS102) chr. 20p mutation usually Pro102Leu, octapeptide repeats also occur.
Findings on Investigations:
EEG: slowing
MRI:
- Normal or cerebellar atrophy
- T2 hypointensity in basal ganglia (iron)
SPECT: abnormal cerebral SPECT findings.