The Dominantly Inherited Alzheimer Network (DIAN) is a research group that focuses on studying early-onset, genetically inherited forms of Alzheimer’s disease and is based in Washington University in St. Louis, MO, USA. The DIAN Expanded Registry (DIAN EXR) is a research registry that exists to help find individuals who may be eligible to participate in DIAN studies. Ambulatory research in cognition (ARC) is a DIAN study that involves participants completing brief, game-like tests on their smartphones in order to examine levels of cognitive function over time. This app may only be used by individuals who are registered with the DIAN EXR and have enrolled in the DIAN ARC research study.