Alzheimer's Disease and Dementia

Study Notes

Alzheimer's disease is a fatal neurodegenerative disorder affecting 1-2% of the US population.
In 2015, around 44 million people worldwide had AD, with 4.6 million new cases predicted each year.

Three major risk factors for AD: • Age – 65 and over • Gender – female • Family history
Other risk factors: • Obesity • High blood pressure • Head trauma • High cholesterol • Diabetes • Down syndrome • Living in America • Higher rates in Japanese-Americans and African-Americans • Lower rates in highly educated people • Beneficial consequences of learning and memory

Progressive deterioration of memory and cognitive functions
Loss of autonomy requiring full-time medical care
Severe neuronal loss
Aggregation of amyloid β (Aβ) in extracellular senile plaques
Formation of intraneuronal neurofibrillary tangles consisting of hyperphosphorylated tau protein

β-amyloid peptide (Aβ) and tau protein deposition in the brain
Aβ peptide generated from the larger βAPP protein and found in amyloid or senile plaques in the extracellular space of AD brains
Amyloid plaques also contain other proteins like apoE
Tau protein expressed in high levels in neurons of the brain
Hyperphosphorylated forms of tau form inclusions, neurofibrillary tangles, inside AD neurons
Phosphorylation diminishes tau protein's normal function of promoting the assembly and stability of microtubules