Final answer:
Prion diseases result in the accumulation of misfolded prion proteins in the brain, forming neurofibrillary tangles and amyloid plaques, leading to a spongy brain texture and severe neurological decline. These are fatal, incurable conditions that result in memory loss, motor impairment, and ultimately death. Diagnosis typically involves histological examination, with medical efforts aimed at patient comfort.
Step-by-step explanation:
Over the course of a prion disease, several critical changes occur in the brain. Prions are misfolded rogue forms of a normal cell protein (PrPc) that can become infectious and convert other normal proteins to their misfolded state, accumulating as PrPsc. This aggregation forms fibrils, resulting in neurodegeneration.
The presence of neurofibrillary tangles and amyloid plaques causes the brains of infected individuals to take on a spongy appearance, leading to the term spongiform encephalopathy. These changes are associated with neurological symptoms like memory loss, personality changes, uncoordinated movements, insomnia, and in late stages, coma and death. In diseases such as Alzheimer's, Mad Cow Disease, and Creutzfeldt-Jakob Disease, prions are implicated in the damage and loss of brain cells, which manifests in various forms of dementia and motor coordination loss.
Unfortunately, there is no cure for prion diseases, and they progress quickly after symptoms appear. Diagnosing these conditions often involves looking for amyloid plaques, vacuoles, and prion proteins in brain biopsies. Current medical support is focused on providing comfort to patients, as the diseases are fatal and cause severe disability before leading to death.