Nonetheless, in APP/PS1 mice, an alternative AD model that overexpresses chimeric mouse/human APP and mutant human presenilin 1 (PS1) under the control of mouse prion protein (PrP) promoter elements, the hearing threshold is elevated by approximately 20 dB sound pressure level compared to the threshold in WT mice as early as 3 months of age [11]. This evidence concerns the gene APP and Alzheimer disease.