While doing blood work for his 2022 series “Limitless,” Hemsworth learned he’d inherited the APOE4 gene from both his mother and his father. “They both gave me a copy, but they both gave me the worst copy, which is the four,” he said. Carrying 2 copies is associated with a substantially higher lifetime risk of Alzheimer’s, a disease his grandfather lives with. It isn’t a diagnosis and it isn’t a certainty. Hemsworth stressed the gene is “not pre…