FCER1G and Alzheimer disease: The lysosomal cysteine proteinase Ctss and the high affinity IgE receptor gamma subunit Fcer1g, which were both downregulated in the current study, are associated with Alzheimer's disease (AD), and in particular, Fcer1g is considered as a risk factor for AD (Taguchi et al., 2005; Castillo et al., 2017).