In agreement with findings of early ACAT1 activation in mouse brains of experimental scrapie (Hwang et al., 2009), and in brains of AD (Pani et al., 2011), we also found increased ACAT1 expression in both skin fibroblasts and PBMCs from AD patients (Pani et al., 2009a,b) and in skin fibroblasts from scrapie-affected and scrapie-susceptible sheep (Pani et al., 2007a). Here, ACAT1 is linked to Alzheimer disease.