Hayley Okines: Girl who was born with, and strove to raise awareness of, the premature-aging condition progeria

The rarity of Okines' illness, and her family's wish to raise its profile, made her the subject of a number of documentaries

An amazing young woman: Okines in 2010 (AP)

Progeria is a very rare congenital condition which causes its subjects to age at eight times the usual rate. Hayley Okines, who has died aged 17, had progeria and endeavoured to enjoy her limited time – and raise awareness of the disorder.

Okines was born in 1997 in Arrington, Cambridgeshire and grew up in Bexhill-on-Sea, East Sussex. Her condition was diagnosed at the age of two, when her parents were told that she would probably not live past 13.

She published two volumes of autobiography: Old Before My Time: Hayley Okines' Life with Progeria (2011) and Young at Heart: The Likes and Life of a Teenager with Progeria, which was published last month. "Having progeria is like being in a really exclusive club and once a year we all get together somewhere in the world at the Progeria Reunions," she wrote. The condition currently affects only some 100 children worldwide.

The rarity of the illness, and her family's wish to raise its profile, made her the subject of a number of documentaries. She featured on Channel 5's Extraordinary People – and in Extreme Aging: Hayley's Story, shown on Discovery Health Channel in 2009, Okines is shown coming to terms with the fact that her condition is terminal.

Dr Leslie B. Gordon, medical director of the Progeria Research Foundation, says in the foreword to Okines' most recent book: "When I first met Hayley Okines at a Sunshine Foundation Progeria Reunion in America she was two years old. In those early years, we had no real understanding of progeria... Now I see her when she participates in the Boston Children's Hospital treatment trials and she has grown into an intelligent, beautiful and amazing young woman."

She had contracted pneumonia and died at home.

Marcus Williamson

Hayley Okines, progeria campaigner: born Arrington, Cambridgeshire 3 December 1997; died Bexhill-on-Sea, East Sussex 2 April 2015.