A nine-year-old girl needs to spend 12 hours a day under ultraviolet lights just to stay alive.
When Brianna Minnich and her family travel, they have to take along a portable UV lightbox.
"Her body has become dependent on those lights," said her father, Bob Minnich.
As a baby, Brianna's skin color was unusually yellow. Her parents Bob and Brooke thought it was simply jaundice. But doctors made a devastating diagnosis—newborn Brianna had one of the rarest diseases on Earth.
Brianna suffers from Crigler-Najjar Syndrome. There only 200 known cases worldwide. Without UV light, Brianna's skin and the whites of her eyes will turn yellow.
Dr. Jennifer Janco says Brianna's liver cannot break down bilirubin, a waste product in the blood. If the bilirubin levels get high enough, the effects can be a lot worse than turning yellow.
"It can build up to a toxic or dangerous level in the brain and cause brain damage and hearing loss," said Dr. Janco.
It turns out both parents carried the rare gene. The chances of them ever meeting and having a child with the syndrome? A staggering 500 million to one.
Brianna takes a daily dose of a powerful barbiturate to keep her calm, because stress can also cause her skin to turn yellow.
"When she cried, her tears were yellow, to this day her tears are yellow," said Bob.
Bob says his little girl has come to him with questions that no dad should have to answer.
"With tears coming down her eyes, asking me 'What's gonna happen to me?' For a nine-year-old to ask that question, its heartwrenching," he said.
When night falls, Bob waits until Brianna is asleep to pull off her covers and turn on the UV light. The light of life for this brave little girl.