For example, the PSD-, β-actin-, and Shank3-associated scaffolding protein Homer 1 is decreased in AD but not in SZ brains [unpublished observations; (35)], and the relatively abundant PSD-95-associated DLGAP scaffold protein subtype DLGAP4 is significantly decreased in SZ but not in BD (15). Here, DLGAP4 is linked to Alzheimer disease.