Frontotemporal dementia, the fourth most common cause
of dementia, is a group of disorders that occur when the nerve
cells in the frontal and temporal lobes of the brain are damaged,
causing the lobes to shrink. It is as common as Alzheimer's
disease in people under the age of 65. Frontotemporal dementia can
affect a person’s behavior, personality, language, and movement.
Facts about frontotemporal dementia
About 250,000 Americans have frontotemporal dementia. These diseases
are among the most common dementias that strike at younger ages.
Symptoms typically start between the ages of 40 and 65, but
frontotemporal dementia can strike young adults and those who are older.
The cause of frontotemporal dementia is unknown. Researchers have
linked certain subtypes of frontotemporal dementia to mutations on
several genes. The most common is a mutation called C9ORF72, which was
discovered in 2011. It can cause amyotrophic lateral sclerosis (ALS), often
referred to as Lou Gherig’s disease, and a combination of both
diseases. Other common mutations include MAPT and progranulin.
A family history of frontotemporal dementia is the only known risk
for these diseases. Although experts believe that some cases of
frontotemporal dementia are inherited, the majority of people with
frontotemporal dementia have no family history of it or other types of dementia.