from Section IV - Cognitive Disorders
Published online by Cambridge University Press: 10 January 2011
Alzheimer's disease
Background
Alzheimer's disease (AD) is a devastating progressive neurodegenerative disorder that is the most common cause of age-related dementia, accounting for between 60 and 80% of cases of dementia. In 2008, around 5.2 million Americans had AD, with an approximate annual cost of $100 billion. It is estimated that between 11 and 16 million people will be diagnosed with AD in the United States by 2050 (Alzheimer's Association, 2008).
Neuropathological alterations in AD include synaptic loss and cortical atrophy, buildup of beta-amyloid fragments into the “senile” plaques between neurons identified a century ago, and of tau protein into the hallmark neurofibrillary tangles within dead or dying neurons. Cholinergic and glutaminergic pathways are prominently involved in the pathophysiology of AD. While the genetic bases of sporadic late-onset AD are not yet well understood, there are several genetic factors that have been identified as playing a role in the disease. A small number of AD cases (<5%) are familial in nature and caused by rare mutations in the amyloid precursor protein (APP) or presenilin (PSEN) genes. Presence of the ε4 allele of the apolipoprotein-E (APOE) gene confers increased risk of the more prominent late-onset form of AD, and many studies aiming to identify risk markers for AD focus on these genes.
To save this book to your Kindle, first ensure [email protected] is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.