The HLN channel aired a documentary special regarding the rare and mysterious condition, fatal familial insomnia (FFI).

FFI is a very rare genetic sleep disorder, with less than 40 families diagnosed worldwide. It causes progressively worsening insomnia, which leads to hallucinations, delirium, dementia, and eventually death. There is no cure and is passed on from parent to child. To learn more about this rare sleep disorder, click here.

The documentary is called Something’s Killing Me: A Family Curse, and centers on three families — one Indian, one Italian, and one Australian — who have suffered for generations with FFI.

The film details how suddenly their parents succumbed to the disease, and the stress the families fact after learning they have inherited it too.

Before it was formally named by the medical community in 1986, FFI was misdiagnosed as nervous exhaustion, encephalitis, and even schizophrenia. Doctors were only able to learn about this fatal disease when a member of one of the afflicted families donated his brain, and the scientists found that his thalamus was found to be riddled with holes.

While the documentary is a fascinating and chilling look into a very rare condition that many have never heard of, it does also inspire a sense of hope and determination by those who are living with it and moving forward with their lives.