GRN and Cognitive impairment: In this regard, it is very intriguing that this study shows that Grn+/– heterozygous mice develop several behavioral and neurodegenerative phenotypes, including cognitive impairments and altered anxiety, as well as lipofuscin accumulation, microgliosis, and retinal neurodegeneration, in the Nlk+/– heterozygous background, all of which are similarly observed in human patients with GRN haploinsufficiency (56, 65, 66).