APOE and Alzheimer disease: Among LSDs, NPC1 has considerable phenotypic overlap with AD (for example, paired-helical filaments, cholinergic neurodegeneration, endosome anomalies, disease acceleration by ApoE4, intracellular Aβ/βCTF elevation and modest amyloid deposition36–38); tauopathy has been reported in mouse MPS-III models and intracellular synuclein, and Aβ accumulations are detected in MPS-III brain39.