Valine-129 does not protect

All the victims to date of the new variant CJD thought to have originated from consuming British BSE beef have a particular feature of their native prion proteins, a methionine residue at position 129. In these people, both their prion-coding genes are the same. Other people have at least one of their copies with a valine at position 129: no-one with these arrangements has succumbed to variant CJD. However, this research shows that, in mice at least, having valines results in a different disease rather than no disease.