Prions.. A mutation in the natural proteins that infect the nerve cells in the brain causing its explosion shrinks the size of the injured brain and becomes smaller than normal

Perion:

is the protein that causes infection or disease and is an abbreviation of (micro-protein infectious).

This protein is found naturally in the cells but becomes a pathogen when a mutation occurs and changes in its genes.

Examples of diseases caused by prions include: spongiform encephalopathy, mad cow disease.

Bruins:

Prions can cause a mutation in the natural proteins that infect the brain's brain cells, causing it to explode.

The size of the brain becomes smaller and normal, which is called spongiform encephalopathy.