APP and Alzheimer disease: Similarly, individuals with a rare familial trait known as duplication of APP (Dup-APP), also develop early onset AD (Rovelet-Lecrux et al., 2006, 2007; Sleegers et al., 2006; Kasuga et al., 2009; Thonberg et al., 2011; Hooli et al., 2012; McNaughton et al., 2012; Swaminathan et al., 2012; Wiseman et al., 2015).