Individuals with AD pathology were also separated into autosomal-dominant presenilin-1 mutation carriers, early-onset (before 65 years) and late-onset groups to investigate patterns of atrophy reported in relation to these often quite distinct disease phenotypes.17 18 Individuals with FTLD-tau were stratified based on the predominant tau isoform found at post-mortem. This evidence concerns the gene PSEN1 and Alzheimer disease.