Cahill, who was born in Elmhurst, Illinois shot to fame in 2010 with his YouTube clips, rapping and lipsyncing and even gained the attention of celebrities who featured in his videos. Cahill’s YouTube videos garnered over 500 million views after they went viral.
Jennifer Aniston, Katy Perry, 50 Cent and Justin Bieber all took part in duets with the young entertainer.
Other big names on his channel included Maroon 5, Flo Rida, Jason Derulo, Gym Class Heroes, Cody Simpson, Tinie Tempah, The Wanted, Big Time Rush, Glee and more.
He also featured in music videos for Sara Barilles’ music video for Uncharted, and released three singles on iTunes: Hands Up, Closer and Back to Us.
Cahill even got to perform on stage with LMFAO during the 2011 American Music Awards and was previously nominated for a Teen Choice Award for Choice Web Star.
Fans have flocked to Cahill’s most recent Instagram post following the news, sharing their messages and memories.
“You were such a huge part of my childhood. Rest In Peace,” one shared.
“Core YouTube childhood memories from you. Fly free in the eternal sky,” another one added.
The internet star was diagnosed with Maroteaux–Lamy syndrome at the age of 1.
He had previously received a bone marrow transplant in 1997 to slow down the progression of the disease and had other surgeries following the transplant.
According to Medline Plus, Maroteaux-Lamy syndrome is a progressive condition that causes many tissues and organs to enlarge, become inflamed or scarred, and eventually waste away.