Some people have a genetic predisposition for developing prion diseases. Examples are described in Table 24.6. In the case of Gerstmann-Straussler-Scheinker disease, the age of onset is typically at 30-50 y8ears, and the duration of the disease (which leads to death) is about 5 years. Suggest a possible explanation why someone can live for a relatively long time without symptoms and then succumb to the disease in a relatively short time.