CERS5 and Alzheimer disease: In reactive astrocytes of patients with late-onset AD, frontotemporal lobar dementia, and capillary cerebral amyloid angiopathy, high ceramide levels and an increased expression of ceramide synthase 5, the enzyme responsible for Cer(d18:1/16:0) production, were observed (van Doorn et al., 2012; de Wit et al., 2016, 2019).