Atypical variants—PSP-parkinsonism (PSP-P), PSP-CBS, PSP-progressive nonfluent aphasia (PSP-PNFA), PSP-behavioral variant frontotemporal dementia (PSP-bvFTD), and PSP-cerebellar ataxia (PSP-C)—exhibit diverse symptom profiles, reflecting variable tau distribution [3]. This evidence concerns the gene MAPT and cerebellar ataxia.