Prion diseases primarily affect which part of the body?

Prion diseases are neurodegenerative disorders caused by misfolded proteins known as prions. These abnormal proteins accumulate in neural tissues, leading to progressive damage to neurons and the disruption of normal brain function. The hallmark of prion diseases is their impact on the nervous system, which is evident in conditions like Creutzfeldt-Jakob disease, kuru, and bovine spongiform encephalopathy.

Symptoms often include cognitive decline, motor dysfunction, and various neuropsychiatric manifestations, highlighting the detrimental effects of prion accumulation in the brain and central nervous system. Unlike other systems in the body, such as the digestive, immune, or cardiovascular systems, prion diseases specifically target neural tissues, underlining their classification as diseases of the nervous system. This defines the correct answer to the question, as all prion diseases are fundamentally linked to neurological impairment.