The 26-year-old — who shares a story similar to Shailene Woodley in the 2014 film opposite Ansel Elgort — had been suffering from the genetic disorder since birth, but lost her battle early Thursday morning in Kentucky, just a day after Dalton's funeral.
Katie's mother Debbie shared the news of her daughter's death in a heartbreaking-yet-uplifting Facebook post shortly after she died, saying:
"Dalton was waiting with open arms, as well as both her grandmothers, and a host of family and friends that have gone before her. I know it is selfish to be sad, I had her so many days, but she is in the arms of Jesus today and she can breathe without oxygen, she no longer has to do dialysis and He has taken away all the pain she endured."
While the lung disease was clearly the source of Katie's physical pain, we're sure enduring five days of a broken heart didn't help the matter.