GBA1 and amyotrophic lateral sclerosis: Apart from the initial stages of cell entry, glucosylceramide synthase and glucosylceramidases play multiple roles in enveloped virus replication [44,45,46,47,48] and are therefore critical hubs for both viral infection and neurodegenerative diseases (Figure 1 and Figure 2), controlling the synthesis and breakdown of GSLs and their interaction with lipid rafts, which have been directly linked to neurodegeneration in ALS [49].