Alzheimer disease late-onset Alzheimers disease true Alzheimer Type Senile Dementia http://www.webmd.com/alzheimers/guide/alzheimers-types late-onset Alzheimer's disease Senile Dementia, Alzheimer Type Alzheimer Senile Dementia late-onset Alzheimer's This is the most common form of the disease, which happens to people age 65 and older. It may or may not run in families. So far, researchers haven’t found a particular gene that causes it. No one knows for sure why some people get it and others don’t. Sirarat Sarntivijai