[testing positive for the disease but it's not progressing] -- Yes, exactly this. There are people with two copies of the bad APOE4 gene. 95% of them develop early-onset Alzheimer's in their 50s. The medical community is now very intensely studying the remaining 5% to find out what's causing them to NOT get sick.
Sloppy wording. -- Fortea (2024) -- Over 95% of people with two copies have amyloid beta in their cerebrospinal fluid. (not full-blown Alzheimers symptoms, just early detection)
