MAPT and Primary lateral sclerosis: Some patients with pathologically confirmed PSP have presented with CBS,[8] progressive apraxia of speech,[11] frontal type dementia,[15] spastic paraparesis resembling primary lateral sclerosis,[16] and parkinsonian features including Lewy body dementia and response to dopamine replacement therapy.[4,17] This clinical variability of PSP is probably caused by the distribution of tau-pathology and its density in the different brain structures.[9,10,12]