Either of these theories [not enough good protein/too much bad protein] could contribute to disease, yes. The correct function of the disease-causing 'major pr

Either of these theories [not enough good protein/too much bad protein] could contribute to disease, yes. The correct function of the disease-causing 'major prion protein' in humans is not known, so I think the answer is "we don't quite know which of these factors is more important". We observe that diseased brains have 'plaques' where they have been turned into sponge, so-called "spongiform encephalopathy". The brain's neurons have simply died, one way or another.