The Haitian-American model, whose full name was Cacsmy Brutus, died on Monday after falling ill on a trip to London, her family wrote in an Instagram post.
Cax had lost her leg to lung and bone cancer as a teenager, and was a powerful advocate for women of colour and disabled women in fashion.
“To say that Cax was a fighter would be an understatement,” her family’s statement said.
“As a cancer survivor, she had grown accustomed to taking on life’s several challenges head on and successfully. It is with that same grit… that she fought her last days on earth.”
Cax first found fame through her blog, in which she wrote frankly and honestly about disability – alongside posts about fashion, travel and general lifestyle.
She later became known for her distinctive street style, and for decorating her prosthetic leg in bold ways.