GRN and amyotrophic lateral sclerosis: Remarkably, trehalose, an mTOR-independent activator of autophagy which exerts beneficial effects in both ALS and SBMA models [10,101,102,103], enhances PGRN expression in both iPSC-derived human neurons carrying a PGRN mutation and in the brains of PGRN haploinsufficient mice [104].