Hayley Okines, from Bexhill, in East Sussex, became known as the “100-year-old teenager” as she suffered from the condition known as progeria.
Her death was announced by her mother, Kerry, on her Facebook page.
She wrote on Thursday night: “My baby has gone somewhere better. She took her last breath in my arms at 9.39pm.”
Hayley and her family had carried out a fundraising campaign for her medical treatment and to raise public understanding of the condition, and the teenager published her autobiography at the age of 14, called Old Before My Time.
After her death was announced, The Progeria Research Foundation posted on its Facebook page: “The entire Progeria family mourns together with many as we say goodbye to Hayley Okines, our smart, beautiful and spirited English rose, who passed away today at age 17.
“Gone from our sight, but never our memories, gone from our touch but never our hearts. We will miss you.”
Hundreds of comments have been left on Hayley’s Facebook paying tribute to the teenager.
Ann Morrison wrote: “Praying for the family and friends of Hayley. God bless you Hayley.
“Your positive outlook and willingness to share your life’s journey with us has been very much appreciated.”
Scientists are particularly interested in research into progeria, which was first described by scientists in 1886, as the condition might reveal clues about the normal process of ageing.