A teenage girl has a second skeleton growing inside her that threatens to eventually 'freeze' her body.
Seanie Nammock, 18, suffers from a condition known as 'stone man syndrome' or fibrodysplasia ossificans progressiva.
It is so rare it affects only 45 people in the UK. The condition turns muscles, ligaments and tendons into solid bone.
It means a second skeleton is growing on top of the original one, with her limbs becoming solid like a statue.
Seanie's back and neck are frozen already, leaving her unable to lift her hands above her waist.
Now doctors are racing to find a way of treating the A-level student from Birmingham – but she lives in constant fear of the condition getting worse.
Seanie's mum Marian, said: "We dread the thought of her second skeleton spreading to the lower part of her body.
"She will have a life-changing decision to make about whether she wants to stay in a sitting down or lying down position... because that's how she will be for the rest of her life."
Any kind of bump or blow to Seanie's body can trigger a painful growing spurt that adds to the second skeleton.
Seanie said: "It doesn't help that I'm accident-prone. I'm always falling up or downstairs because I can't hold the banister.
"My balance is also a problem because of the way my arms are locked. I can't put them down to break my fall either – so it can be really scary."
The only treatment available to the world's 600 FOP sufferers like Seanie is taking over-the-counter painkillers.
But doctors at Birmingham's Queen Elizabeth Hospital want to change that by setting up a world-class rare disease centre where conditions such as Seanie's can be researched and treated.
They say setting up a centre could not only help find a cure for Seanie's illness, it may also aid osteoporosis sufferers and others with bone diseases.