Grn − / −, but not Grn + / − mice, develop progressive
gliosis, inflammation, and lipofuscinosis in several brain regions that first becomes detectable around 6 — 7 months of age and is more strongly elevated
by 12 months (Ahmed et al., 2010; Yin et al., 2010; Wils et al., 2012; Filiano et al., 2013; Götzl et al., 2014).