Although genetic data and functional analyses in animal models provide some evidence for an involvement of PGRN in AD, no changes in CSF PGRN in AD compared to healthy controls have been reported so far (Nicholson et al, 2014; Körtvélyessy et al, 2015; Morenas‐Rodríguez et al, 2015; Wilke et al, 2017). This evidence concerns the gene GRN and Alzheimer disease.