"My heart is shattered into a million pieces... my beautiful loving sister Deondra has transitioned... I say transitioned because she will always be alive... anyone who knew my sis... knew that she was a bright light...," Jamie Foxx wrote. "I can't tell you how many times we have had parties at the house where she has got on the dance floor and stolen the show."
Dixon was well known for her admiration for singer Chris Brown, and her brother joked that when it came to dancing, she "even gave her boyfriend @chrisbrownofficial a run for his money."
"Well I know she is in heaven now dancing with her wings on...tho my pain is unbelievable I smile when I think of all of the great memories that she left me... my family... and her friends," he wrote.
Jamie Foxx also noted the times she joined him in his craft from dancing in the music video for his single "Blame It" to appearing with him at the Grammys.
"Deondra you have left A hole in my heart... but I will fill it with all of the memories that you gave me ... I love you with every ounce of me," Jamie Foxx wrote. "Our family is shattered but we will put the pieces back together with your love... and y'all please keep my family in your prayers..."
Jamie Foxx also wrote in his post that his sister was an ambassador for the Global Down Syndrome Foundation.
The organization honored Dixon on its site in a post that noted "The Global Down Syndrome Foundation's highest honor, the Quincy Jones Exceptional Advocacy Award, was inspired by DeOndra and she was its first recipient. Quincy Jones himself introduced us to DeOndra as one of the most articulate, irrepressible, magnetic people he had ever met."
"Her parents, Annette and George Dixon, brother Jamie Foxx, sister Deidra Dixon, nieces Anelise and Corinne, dear friend Kim, and large extended family are beyond consolable, and we ask that you help us respect their privacy during this difficult time," the tribute read. "For Global, we have lost our talented, intelligent, feisty, beautiful, kind, loving, caring, pure and giving heart, DeOndra Dixon. Our Down syndrome community has lost a beacon of hope, a true leader, and role model whose aim was to always help others. She was a bright light in this world of ours."