Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Alzheimer's Disease ?
    ### Response:
    There are two types of Alzheimers diseaseearly-onset and late-onset. Early-onset Alzheimers is a rare form of the disease that occurs in people age 30 to 60. It occurs in less than 5 percent of all people with Alzheimers. Almost all people with Alzheimers disease have late-onset Alzheimer's, which usually develops after age 60.
    