The genetic answer came back, and it was nothing. A study of 142 adults in their 80s and 90s with the memory of people decades younger found that they could not be distinguished from cognitively average peers by APOE status, by any of the three Alzheimer's polygenic risk scores tallying thousands of variants, or by rare protective variants previously linked to resilience.
That result closes a door, which is useful. It also makes a different body of evidence considerably more interesting. Northwestern's SuperAging program has been examining donated brains from these individuals since the 1990s, and those brains are anything but ordinary.
