For example, the Drosophila gene amyloid precursor protein-like (Appl) gene encodes a protein product (APPL) (Rosen et al. 1989) that is orthologous to the human amyloid beta precursor protein (APP) associated with Alzheimer’s disease (Kang et al. 1987). This evidence concerns the gene APPL1 and early-onset autosomal dominant Alzheimer disease.