Chris Hemsworth's announcement on his health condition in his new show “a mission to live better for longer” on Disney Plus came like a bolt from the blue. The 39-year-old “Thor” Hollywood star discovered that he had a rare genetic combination of 2 copies of the APOE4 gene, which is associated with an increased risk of Alzheimer's disease. According to a 2021 study by the National Institutes of Health, APOE4 is the highest risk factor gene for Alzheimer’s disease, yet inheriting ApoE4 does not guarantee to develop the disease.