Below is an instruction from Human. Write a response.
    ### Instruction:
    What is the outlook for Alzheimer's Disease ?
    ### Response:
    In very few families, people develop AD in their 30s, 40s, and 50s. This is known as "early onset" AD. These individuals have a mutation in one of three different inherited genes that causes the disease to begin at an earlier age. More than 90 percent of AD develops in people older than 65.
    