Is Alzheimers disease genetic?
There are a few very rare cases in which Alzheimer’s disease does run in families. In these cases, there is a direct link between an inherited mutation in one gene and the onset of the disease. These tend to be cases of early-onset Alzheimer’s disease — affecting those under age 65. In these cases, the probability that close family members (brothers, sisters and children) will develop Alzheimer’s disease is one in two. Most cases of Alzheimer’s disease are not of the type that is passed on directly in this way. If a family member has a normal form of Alzheimer’s disease, the risk to close relatives is around three times higher than the risk for a person of a similar age who has no family history of the disease. It is thought that, in these cases, a person’s genes may contribute to the development of the disease but do not cause it directly.
