**Core Concept**
Prion diseases, also known as transmissible spongiform encephalopathies (TSEs), are a group of rare, fatal brain disorders caused by an infectious agent called a prion. Prions are misfolded proteins that can induce normal proteins to misfold, leading to cell death and neurodegeneration.

**Why the Correct Answer is Right**
Prion diseases are characterized by the accumulation of prion protein (PrP) in the brain, which leads to neuronal damage and cognitive decline. Examples of prion diseases include Creutzfeldt-Jakob disease (CJD), Gerstmann-Sträussler-Scheinker disease (GSS), and fatal familial insomnia (FFI). These diseases are typically inherited in an autosomal dominant pattern, meaning a single copy of the mutated gene is sufficient to cause the disease.

**Why Each Wrong Option is Incorrect**
**Option A:** Alzheimer's disease - This is a different type of neurodegenerative disorder caused by the accumulation of amyloid beta plaques and tau protein tangles, not prions.

**Option B:** Huntington's disease - This is a genetic disorder caused by an expansion of CAG repeats in the Huntingtin gene, leading to neurodegeneration, but it is not a prion disease.

**Option C:** Parkinson's disease - This is a neurodegenerative disorder caused by the loss of dopamine-producing neurons in the substantia nigra, but it is not a prion disease.

**Clinical Pearl / High-Yield Fact**
Prion diseases are unique in that they can be transmitted through contaminated tissue, such as through medical procedures or consumption of contaminated meat, making them a concern for public health.

**Correct Answer: C. Gerstmann-Sträussler-Scheinker disease (GSS).