In this study, all of our cases were symptomatic (CDR ≥ 1), although we note that behavioral and cognitive changes can emerge in the presymptomatic and prodromal stages of bvFTD, many years before dementia and diagnosis29, 30; and synaptic loss has been identified in the presymptomatic stage of those with highly penetrant mutations such as C9orf72 expansions.16 This evidence concerns the gene C9orf72 and behavioral variant of frontotemporal dementia.