PSEN1 and Alzheimer disease: In the APP-PSEN1/+ AD mouse model, the IB4+ vascular anomalies were found in regions containing Aß plaques, including the cortex, hippocampus, and the corpus callosum (Fig. 3e–g and Supplementary Movie 1), covering up to 5% of the total cortical surface (Fig. 3h) and not detected in WT mice (Fig. 3h).