"Hayley was a pioneer - and one of the reasons that we now have the first treatment for progeria. Today we remember her tremendous courage and determination," said the Progeria Research Foundation.
Progeria, or Hutchinson-Gilford Progeria Syndrome (HGPS), affects around 1 in 4-8 million newborns worldwide. There are approximately 200-250 children living with the condition across the globe at any one time.
Progeria is caused by an abnormal protein in the LMNA gene, called progerin, which interferes with the production of lamin A - a protein that stabilizes a cell's nucleus. This disruption causes children with progeria to age up to 10 times faster than normal.
On Thursday evening, it was announced that 17-year-old progeria sufferer Hayley Okines - from Medical News Today's hometown Bexhill in East Sussex, England - had passed away.
Hayley's mother, Kerry Okines, posted the sad news on Facebook: "My baby girl has gone somewhere better. She took her last breath in my arms at 9.39 pm."
Hayley - who BBC News say had the "body of a 104-year-old" - was being treated in the hospital for pneumonia, but she returned home shortly before she died. "She came home for an hour and she saw her puppies, little brother Louie and her sister Ruby," Hayley's father, Mark Okines, told BBC News on Friday.
"I think she wanted to come home to say goodbye to everybody," he continued. "I think she knew that yesterday was going to be the time."
'We remember her tremendous courage and determination'
Hayley was told she would not live past the age of 13, but in 2007, the teenager began undergoing pioneering treatment at Boston Children's Hospital, MA, as part of the first clinical trial for the condition.
In September 2012, MNT reported on the success of this trial, revealing how a farnesyltransferase inhibitor (FTI) improved the weight, bone structure and cardiovascular health of children with progeria.
In a statement following Hayley's death, the Progeria Research Foundation praised the teenager for her contribution to progeria research:
"The entire PRF community mourns the loss of one of our shining stars, Hayley Okines. Hayley was one of the first participants in the ongoing progeria clinical trials. Hayley was a pioneer - and one of the reasons that we now have the first treatment for progeria. Today we remember her tremendous courage and determination."
Hayley was an avid campaigner for progeria awareness, hailed locally and nationally as an inspiration for people with and without the condition. The teenager penned two books detailing her experiences of living with progeria - "Old Before My Time" and "Young at Heart" - and took part in numerous interviews.
As well as for her contribution to progeria awareness and research, Hayley was highly admired for her positive outlook on life, writing in "Young at Heart:"
"My life with progeria is full of happiness and good memories. Deep inside I am no different from anyone. We are all human."
Our thoughts and prayers are with Hayley's family and friends at this difficult time.
The news of Hayley's death comes just 15 months after it was announced Sam Burns, a boy from Foxborough, MA, had died from progeria aged 17.