Biochemical aetiology of Alzheimer’s disease relates to
**Core Concept**
Alzheimer's disease is a complex neurodegenerative disorder characterized by progressive cognitive decline, with a significant biochemical component contributing to its pathogenesis. The disease is associated with the accumulation of amyloid-beta peptides and tau protein in the brain, leading to neuronal damage and death.
**Why the Correct Answer is Right**
The correct answer involves the biochemical pathway known as the amyloid cascade hypothesis. Amyloid-beta peptides are generated from the amyloid precursor protein (APP) through the action of the enzymes beta-secretase and gamma-secretase. The accumulation of amyloid-beta peptides in the brain triggers a series of downstream events, including oxidative stress, inflammation, and tau phosphorylation, ultimately leading to neuronal loss and cognitive decline. The amyloid cascade hypothesis provides a framework for understanding the biochemical aetiology of Alzheimer's disease.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the biochemical aetiology of Alzheimer's disease. While oxidative stress and inflammation are contributing factors, they are not the primary biochemical mechanisms involved in the disease's pathogenesis.
**Option B:** This option is incorrect because it refers to a different disease process, specifically the buildup of tau protein in frontotemporal dementia. While tau protein is also involved in Alzheimer's disease, the correct answer focuses on the amyloid-beta peptides.
**Option C:** This option is incorrect because it refers to a different biochemical pathway, specifically the ubiquitin-proteasome system. While this system is involved in protein degradation, it is not directly related to the biochemical aetiology of Alzheimer's disease.
**Clinical Pearl / High-Yield Fact**
A key feature of Alzheimer's disease is the presence of amyloid plaques and neurofibrillary tangles in the brain, which can be visualized using imaging modalities such as PET scans. This is a critical diagnostic clue, as it helps distinguish Alzheimer's disease from other forms of dementia.
**Correct Answer:** C.