DLGAP3 and early-onset autosomal dominant Alzheimer disease: Among the proteins encoded by these genes, Dlgap3 (PSD95-associated protein 3) is an excitatory postsynaptic protein implicated in the pathogenesis of obsessive-compulsive behaviours [85], and Snap-25 is a component of the SNARE protein complex and a promising cerebrospinal fluid biomarker for synapse degeneration in Alzheimer’s disease [10].