11.   It causes disease, Prusiner said, when it nestles against normal prion proteins and makes them change their shapes.

12.   Mice lacking the gene appear healthy, suggesting that the normal prion protein is not an essential protein in mice.

13.   Most doctors believe that sCJD is caused by a prion protein deforming by chance into a killer.

14.   Normal prion protein is produced by a gene that is widely found in nature.

15.   Normally, prion protein has a particular structure, or label, that is recognized by other proteins in the endoplasmic reticulum.

16.   Once it gets into a body, each prion protein latches onto a normal protein and transforms the good protein into a bad prion one.

17.   Prusiner warned that prion proteins could jump from one species to another.

18.   Prusiner said that the infectious prion protein is just like the normal one except that it is folded into a different shape.

19.   The corrupted prion protein then accumulates in the brain to the point where it causes neurodegenerative disease.

20.   The disease is linked to an altered or abnormal form of the prion protein usually found in animals.