F.F.I. is caused by anaccumulation within the thalamus — the part of the brain that controlssleep regulation — of abnormal proteins called “prions.”

丘脑是大脑中负责睡眠调控的部分，致死性家族性失眠症正是由于一种异常蛋白质“朊蛋白”在丘脑中的累积产生的。

youdao

At present doctors test for the presence of abnormal proteins called prions which are thought to cause the disease by killing off brain cells.

BBC: NEWS | Health | Hopes for better vCJD diagnosis

Scientists had long assumed that these disorders must be caused by a virus, but Prusiner had proposed back in 1982 that deformed proteins, called prions, were the culprit.

FORBES: Health

Prusiner proved that prions are a deformed version of an otherwise harmless protein called PRP.

FORBES: Magazine Article