Gerstmann-Str ä ussler-Scheinker syndrome (GSSS) is a genetic variant of prion disease due to a missense mutation in the PRNP gene. 1-2 It presents with progressive cerebellar ataxia, dysarthria, athetosis, and late-onset dementia. 1 Median age of onset is by the fifth decade, however phenotypic variability exists among different families due to polymorphisms in codon-129. 1-2 MRI shows multifocal symmetric hyperintensities in th e basal ganglia, thalamus, and cortex. EEG reveals continuous slowing with