A woman and her husband completely changed career paths to study a deadly disease that killed her mother she learned she inherited.

Sonia Vallabh was studying at Harvard Law school in 2010 when her mother became ill. She had trouble seeing, lost her memory and spoke in tongues.

“She was fitful and couldn’t really tell you if she’d been awake or asleep,” Vallabh told CNN. Her mother died in December of that year at 52. Shortly after, Vallahb learned that her death was caused by an extremely rare genetic disease known as fatal familial insomnia (FFI.)

BABY WHOSE MOTHER CHOSE TO GIVE BIRTH OVER CHEMOTHERAPY DIES

FFI wasn’t given a name until 1986 and only affects a few dozen families throughout the world. Caused by a brain abnormality similar to mad cow disease, FFI patients suffer a months-long descent into a dementia-like state as the brain loses its ability to fall asleep.

“There’s this one protein that’s sort of at the heart of this disease, the prion protein,” Vallabh said. “This is a protein that we all have. We’re all producing it all the time and it’s part of normal biology, but it’s capable of undergoing … a change in shape.”

If a change in shape occurs, the prions begin to create abnormal prions which then begin to kill brain cells as they spread. In FFI patients, the abnormal prions attack the thalamus, the center of our brain which controls consciousness, sight and sleep.

Most of the information on the disorder has been gathered from a family in Venice, Italy, whose line has have suffered from FFI for more than two centuries.

This article first appeared on NYPost.com.