I am noticing some changes in memory of a friend who is only 55. Is dementia not a disease of the elderly?
Alzheimer's disease or a related dementia is most often found in the elderly with symptoms usually appearing in the 60's. Early onset occurs in people age 30 to 60 and represents less than 5 percent of all people with Alzheimer’s. Most cases are caused by an inherited change in one of three genes, resulting in a type known as early-onset familial Alzheimer’s disease, or FAD. For others, the disease appears to develop without any specific, known cause, much as it does for people with late-onset disease.