PROS1 and Alzheimer disease: Moreover, the selective decline in PSA-NCAM in hippocampal and cortical regions underscores the vulnerability of these areas to AD-related synaptic deficits and highlights the potential of PSA-NCAM as a therapeutic target, as seen in other studies (Senkov et al., 2006; Varbanov and Dityatev, 2017; Pinky et al., 2023; Varbanov et al., 2023).