of Geriatric Medicine, Karolinska University Hospital, Sweden, patients with a suspected genetic cause of AD are referred for mutation screening in the genes APP, PSEN1, and PSEN2. In addition to using sequencing for mutation screening, we have developed a protocol for analyzing the copy-number of APP. The protocol includes both a microsatellite analysis and a copy-number assay. The gene discussed is APP; the disease is Alzheimer disease.