today, in a region of colombia called antioquia, reality appears to be imitating fiction, in a way thatanswer questions for all of us. antioquia is home to the largest concentration in the world of people who carry a rare genetic mutation that makes them 100% certain to develop alzheimer's disease. and as devastating as alzheimer's is anywhere, this is a particularly cruel version-- it strikes when people are in their mid-40s, and leads to death about a decade later. it is a tragic situation, but a perfect scientific laboratory. and it's now the center of a multi-million dollar, n.i.h.- backed study that's trying to find out, for the first time, whether alzheimer's disease may be preventable. these are the andes mountains and lush countryside of antioquia, colombia, whose capital city, medellin, was once famous for murder and the drug cartel of pablo escobar. today, medn- it's pronounced here-- is peaceful. but for some families here, there's still a battle going on. a battle against an insidious disease. this family-- mother cecilia, her seven children, and grandchildren-- lost its pat