Alzheimer disease type 4

Early-onset, autosomal dominant Alzheimer disease is a form of Alzheimer disease (AD) that develops before the age of 65. It is diagnosed in families that have more than one member with AD (usually multiple persons in more than one generation) in which the age of onset is consistently before age 60 and often between the ages of 30 and 60 years. In general, AD is a degenerative disease of the brain that causes gradual loss of memory, judgement, and the ability to function socially.

There are three subtypes of early-onset familial AD which are each associated with changes (mutations) in unique genes:

(1) Alzheimer disease, type 1 is caused by mutations in the APP gene
(2) Alzheimer disease, type 3 is caused by mutations in the PSEN1 gene
(3) Alzheimer disease, type 4 is caused by mutations in the PSEN2 gene.

All subtypes are inherited in an autosomal dominant manner. There is no cure for AD. Treatment is supportive and based on the signs and symptoms present in each person.