NPC1 and Alzheimer disease: Indeed, hippocampus and frontal cortex of patients with AD and AD-Tg mice have been shown to exhibit increased expression of the lysosomal cholesterol transporter NPC1 [3], while increased steroidogenic acute regulatory protein (STARD1) expression, which regulates the mitochondrial cholesterol trafficking [4], has been reported in pyramidal hippocampal neurons of patients with AD [5].