NEU1 and sialidosis: Immunofluorescence analysis of the sialidosis-iNPCs with an anti-NEU1 antibody showed a similar punctate endo-/lysosomal staining pattern as seen in the normal-iNPCs, while the expression of NEU1 in the sialidosis-iNPCs (G227R-iNPCs and V275A/R347Q-iNPCs) had a more perinuclear distribution compared with that of the normal-iNPCs (Figure 3A).