PSEN1 and Alzheimer disease: We crossed an Alzheimer’s model mutant APPKM670/671NL/PSEN1Δexon9(APP/PSEN1) mouse model with Tyrobp−/− mice to generate AD model mice deficient or null for TYROBP (APP/PSEN1; Tyrobp+/− or APP/PSEN1; Tyrobp−/−).