They reported an increased tau pathology in the mid-frontal and inferior-parietal cortices in PSP-CBS compared with PSP-RS and concluded that the CBS presentation of PSP was either caused by a concurrent cortical pathology from a secondary process such as Alzheimer's disease or primary PSP tau pathology involving the cortical regions 12. The gene discussed is MAPT; the disease is early-onset autosomal dominant Alzheimer disease.