Consistent with previous observations in sialidosis-NPCs carrying NEU1D176G or NEU1P316S [21], loss of NEU1 enzyme activity in NEU1G227R- and NEU1V275A/R347Q-iNPCs is coupled with increased expression of LAMP1, which is potentially suggestive of impaired lysosomal exocytosis in NEU1G227R- and NEU1V275A/R347Q-iNPCs, but the detailed molecular machinery and regulatory mechanisms require further investigation. This evidence concerns the gene NEU1 and sialidosis.