GRN and frontotemporal dementia: Progranulin‐insufficient mouse models develop FTD‐related pathology and behavioral deficits, implicating progranulin haploinsufficiency as the mechanism by which GRN mutations cause FTD (Ahmed et al. 2010; Filiano et al. 2013; Ghoshal et al. 2012; Lui et al. 2016; Nguyen et al. 2018; Smith et al. 2024; Zhang et al. 2020).