These dysfunctions correlated with reduced cortical thickness and surface area of the right insula in presymptomatic GRN carriers, suggesting that glutamatergic impairment in the presymptomatic phases of GRN-related FTD could reflect the beginning of insular dysfunction, even in absence of cognitive or behavioral abnormalities (Gazzina et al., 2018). Here, GRN is linked to frontotemporal dementia.