Two transgenes inserted at a single locus in Chromosome 9 between Arpp21 and Pdcd6ip. Each transgene is controlled by the mouse prion promoter and contains a cDNA sequence. In one transgene the cDNA encodes a chimeric amyloid beta (A4) precursor protein (APPswe). In the second transgene the cDNA encodes the "DeltaE9" mutation of human presenilin 1. The DeltaE9 mutation of the human presenilin 1 gene is a deletion of exon 9 and corresponds to a form of early-onset Alzheimer's disease. The amyloid beta precursor protein coding sequences were altered by replacing mouse sequence encoding three amino acids of the A-beta domain with the human coding sequence for these residues. (J:293217)