For the past three decades the largest family in the world with a genetic form of Alzheimer’s disease has been tracked. This extended family of some 5,000 individuals live in Antioquia, Colombia among a people who call themselves Paisa. Passing relentlessly through the generations with 100% penetrance is a mutation that causes early onset Alzheimer’s disease in its carriers. Dr. Kenneth Kosik explains that the mutation in the Americas likely originated from a Spanish conquistador whose progeny are the members of the family we see today. Recently, interest in the family has grown because they are now participating in a clinical trial intended to delay the onset of the disease. Series: "The Brain Channel" [Health and Medicine] [Science] [Show ID: 31481]