ALZHEIMERS
Alzheimer's
disease (AD), also called Alzheimer disease or simply Alzheimer's, is a neurodegenerative
disease that, in its most common form, occurs in people over 65 years old
and is the most common cause of dementia afflicting 24 million people worldwide.The
ultimate cause of Alzheimer's is unknown. Genetic factors are clearly indicated
as dominant mutations in three different genes that account for the small
number of cases of familial, early-onset AD that have been identified. For
the more common form of late onset AD, ApoE is the only clearly established
susceptibility gene. All four genes can contain mutations or variants that
confer increased risk for AD, but they account for only 30% of the genetic
picture of AD. Mutations in any of these four genes lead to the excessive
accumulation in the brain of Aβ, the main component of the senile plaques
that are prevalent in the brains of AD patients.
Clinical signs of Alzheimer's disease include progressive cognitive deterioration,
declining ability to perform activities of daily living, and neuropsychiatric
symptoms or behavioral changes. Plaques which contain misfolded peptides called
amyloid beta (Aβ) are formed in the brain many years before the clinical signs
of Alzheimer's are observed. Together, these plaques and neurofibrillary tangles
form the pathological hallmarks of the disease. These features can only be
discovered at autopsy to confirm the clinical diagnosis. At this time medications
can help reduce the symptoms of the disease, but they cannot change the course
of the underlying pathology.(1)