Which of the following is NOT a prion disease?

• A. Kuru
• B. Scrapie
• C. Alzheimer's disease
• D. Mad cow disease

Answer: (C)

Alzheimer's disease is the correct answer as it is not classified as a prion disease. Prion diseases are caused by the misfolding of prion proteins, leading to neurodegenerative disorders. They include conditions like Kuru, Scrapie, and Mad Cow disease (Bovine Spongiform Encephalopathy).

Kuru is associated with the consumption of infected human brain tissue and includes symptoms like tremors and loss of coordination. Scrapie affects sheep and goats, leading to behavioral changes and eventual neurological deterioration. Mad Cow disease, similar to scrapi, affects cattle and can be transmitted to humans through consumption of infected meat, leading to variant Creutzfeldt-Jakob disease.

In contrast, Alzheimer's disease is primarily characterized by the accumulation of amyloid-beta plaques and tau tangles in the brain. While Alzheimer's involves protein misfolding, it does not involve prions and their mechanisms. This distinction is fundamental in understanding the pathology of neurodegenerative diseases, as the infectious nature of prions sets them apart from Alzheimer's, which is not considered contagious or caused by infectious agents.