"January 12, 2022 at 7pm Adalia Rose Williams was set free from this world. She came into it quietly and left quietly, but her life was far from it," her family share on her Instagram page.
'She touched millions of people and left the biggest imprint in everyone that knew her. She is no longer in pain and is now dancing away to all the music she loves," they added.
The family thanked all nurses and doctors who "worked for years to keep her healthy", as well as everyone who loved and supported her during her life.
In interviews over the years, Adalia and her family spread awareness about what it was really like to live with the genetic condition.
Her mum, Natalia Pallante, was a single parent when Adalia was diagnosed at 3 months old.
"I was a single mom at the time, so when I got the diagnosis I was alone. It was just her and I and I honestly felt lost," Pallante said in an interview a few years ago.
She eventually met her partner Ryan and Adalia got several siblings.
Her mum described Adalia as "rambunctious" and said she loved watching her daughter grow.
"Adalia has changed my life completely, it's not like I was hateful but I wasn't nice to myself. I wasn't thankful. I didn't realise what life was until she was born," she said.
Adalia Rose lived her life to its fullest, in the 15 years she was alive. She loved dressing up and she loved dancing.
Thousands of fans have expressed their condolences after the passing of the popular YouTuber.
"My heart breaks to hear this. I was lucky to have met her and to see how amazing she was. She touched so many people with her amazing energy. I'm so sorry for your family's loss. I will be keeping you in my prayers. Rest in paradise angel," one person wrote.
