To this end, we conducted a multicentre study combining tau-PET (n = 320 cross-sectional, n = 78 longitudinal) and post-mortem (n = 93) data across 14 sites from various atypical AD variants (i.e. PCA-AD, lvPPA-AD, bvAD and CBS-AD). The gene discussed is MAPT; the disease is Alzheimer disease.