APP and early-onset autosomal dominant Alzheimer disease: Triplication of specific regions of chromosome 21, band 21q22, causes various physical and cognitive phenotypes of Down syndrome, and the causative genes include amyloid beta precursor protein (APP) related to Alzheimer’s disease, and superoxide dismutase 1 (SOD 1) involved in the onset of amyotrophic lateral sclerosis [4, 5].