[4] Prusiner discovered prions, a class of infectious self-reproducing pathogens primarily or solely composed of protein, a scientific theory considered by many as a heretical idea when first proposed.

[6][7] He was born in Des Moines, Iowa, into a Jewish[8] family to Miriam (Spigel) and Lawrence Prusiner, an architect.

He spent his childhood in Des Moines and Cincinnati, Ohio, where he attended Walnut Hills High School, where he was known as "the little genius" for his groundbreaking work on a repellent for Boxelder bugs.

Prusiner and his co-workers suggested "One scientific theory, viewed as heretical in that it seems to challenge the role of nucleic acids as the exclusive carriers of genetic information."

[3] In this work, he coined the term prion, which comes from the words "proteinaceous" and "infectious," in 1982 to refer to a previously undescribed form of infection due to protein misfolding.