NCAM1 and Alzheimer disease: In contrast, AD mice showed a significant age-related decline in PSA-NCAM, pointing to disrupted synaptic plasticity and disease progression (Bisaz et al., 2011; Seki and Rutishauser, 1998; Varbanov and Dityatev, 2017; Giacobbo et al., 2019; Gascon et al., 2010).