MSA, besides putaminal and cerebellar atrophy, demonstrates nigrostriatal and olivocerebellar hypometabolism related to αSyn cytoplasmic inclusion (GCI) burden; PSP typically shows midbrain atrophy on structural imaging, whereas PET depicts frontal lobe hypometabolism and confirms underlying tauopathy; CBD displays asymmetric atrophy of the superior parietal lobule and corpus callosum, whereas FDG- and tau-PET demonstrate asymmetric hypometabolism and subcortical involvement contralateral to the side of clinical deficits [158]. The gene discussed is MAPT; the disease is tauopathy.