Yes, PRION is a Scrabble word!

Letter values in Scrabble US: P 3, R 1, I 1, O 1, N 1.

Is it a valid word?

PRION is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

(microbiology) an infectious protein particle similar to a virus but lacking nucleic acid; thought to be the agent responsible for scrapie and other degenerative diseases of the nervous system