The parents of a seven-year-old boy in need of a stem cell donor said they are living on a 'knife edge'.
Finley Hill, from Belbroughton in Warwickshire, suffers from a rare immune system disorder called hemophagocytic lymphohistiocytosis (HLH).
The disorder causes the immune system to overreact, leading to inflammation and damage to tissues such as the liver, spleen and brain.
His parents Jo and Paul are now urging people to sign up and donate in a desperate search for a match for their son.
It took around three years for Finley to get a diagnosis because his initial symptoms, including headaches, mimicked viral infections like glandular fever.
Currently steroid medication keeps Finley 'relatively well' - but it is unclear how long this approach will work.
He urgently needs a transplant to cure him - but Mr and Mrs Hill said most people are unaware the stem cell registry even exists during an interview on ITV's This Morning.
Jo and Paul Hill are urging people to sign up to the stem cell registry in a desperate search for a match for their son, Finley, seven. Pictured during an interview on ITV's This Morning
Finley, from Belbroughton in Warwickshire, is one of very few people with a rare immune system disorder called hemophagocytic lymphohistiocytosis (HLH). Pictured on This Morning with his teddy, Dave
For Finley, his brain was the first to be affected. Some HLH patients develop neurological symptoms including seizures, mood changes, headaches and altered vision
Finley's symptom started in 2016 when he was four years old at nursery, Mrs Hill said
Only two per cent of the UK and 0.4 per cent of the world population are on the register, according to estimates.
This means many people with blood cancer and blood disorders die waiting for a matching donor.
Mrs Hill said: 'They haven’t given a time, but the medication won’t last forever. We’re all on a knife edge.'
HLH symptoms can vary greatly and it involves multiple organs. Generally, affected individuals develop fevers, a rash, and an abnormally large liver and spleen.
To become a potential blood stem cell donor you need to visit DKMS.org.uk.
Your age, location and current health status are important, so you will be asked questions to see if you are eligible to donate.
Anyone between the ages of 18-55 and in general good health can become a potential blood stem cell donor. You must also be permanently living in the UK.
You will receive three cheek swabs that you move around your mouth for a minute each.
Once DKMS receive your swabs, they will analyse your tissue type and add your details on the UK stem cell registry in an anonymised form.
Your details will then be part of blood stem cell donor searches for people all over the world who need a genetic match to get a second chance at life.
The other 10 per cent have the blood taken from the bone marrow in the hip or pelvis. The blood stem cells completely replenish themselves within two to four weeks.
For Finley, his brain was the first to be affected. Some HLH patients develop neurological symptoms including seizures, mood changes, headaches, altered consciousness, and altered vision.
Mrs Hill said: 'When we walk into school that saying goodbye is hard. He'll say, "I have a headache" and I don’t know, I can’t see. I don't know if it's a bit of anxiety or the inflammation is returning.
'We can’t be permanently MRI-ing his head.'
Mr Hill added: 'It is good to hear those footsteps in the morning so we know he is up. It is life on a knife edge.'
Finley's symptom started in 2016 when he was four-and-a-half years old at nursery, Mrs Hill said.
'Finley was complaining of headaches which is weird for a four year old to have headaches,' she added.
'I went back and forward to the doctors and we went to the hospital and they said it was probably a nasty virus.
'Then they said maybe glandular fever but they didn't want to mess him about any further. They expected him to turn a corner by the Monday given the timescales involved.'
But on the Monday, Finley was anything but recovered. Mrs Hill phoned the doctors who told her to go straight to hospital where he had a proper
