NPC1 and mucosulfatidosis: We then evaluated the impact of lysosomal impairment on presynaptic integrity in two other neurodegenerative LSDs, the multiple sulfatase deficiency (MSD; caused by the deficiency of sulfatase modifying factor‐1) and the Niemann–Pick type C‐1 (NPC1; caused by the deficiency of the lysosomal membrane protein NPC1) (Settembre et al, 2008; Sarkar et al, 2013).