Specific missense mutations lack the ability to promote outgrowth and branching in primary hippocampal neurons. (A) Schematic representation of the GRN gene and location of missense mutations investigated (p.S120Y, p.C139R, p.P248L, p.R432C). (B) Bar graph quantification of neurite outgrowth of Grn−/− hippocampal neurons treated with 125 nM (10 ug/mL) of wild-type rPGRN-His or missense rPGRN-His. Data is presented as the mean ± SEM. **p < 0.01; ***p < 0.001.