Atypical forms of AD were previously considered separate conditions to AD; however, cerebrospinal fluid (CSF) and PET biomarkers of AD pathologies, such as CSF Aβ1-42 and PET tau, have shown a significant pathology overlap between AD and atypical forms [7,8], with 67–100% estimated to be logopenic aphasia cases, 76–100% primary cortical atrophy, 7–20% behavioural variant FTD, and 15–50% corticobasal syndrome. This evidence concerns the gene MAPT and Alzheimer disease.