Sitting in Tamara Lord's sunny home, it's impossible to ignore the pictures of her youngest son Dylan that adorn the walls. It's his huge brown eyes and dark eyelashes that first grab the attention. Then you notice that Dylan, who was less than two years old when the photograph was taken, isn't pictured in his bed at home but is sitting in a hospital cot, hooked up to a tube. "The nurses always said they were jealous of his lovely eyelashes," says Lord, 37.
Nurses – and doctors – were Dylan's constant companions during his time in Lewisham and Great Ormond Street hospitals, because Dylan spent more than half of his short life in their care. "Dylan was always smiling," says Lord. "The doctors loved him and they were devastated when he died."
Dylan suffered from X-linked lymphoproliferative disease (XLP) and was just 20 months old when he passed away last July. XLP, also known as Duncan's syndrome, is a rare genetic disorder that only 100 families in the world are known to have. It causes the immune system to respond abnormally to viral infections, which can result in either an underactive or an overactive immune system.
According to the XLP Research Trust, the condition can have many symptoms. About one-third of sufferers develop lymphoma (cancer of the blood cells); one-third suffer from severe glandular fever; and one-third suffer from low levels of immunoglobulin, the proteins in blood that help to fight infection.
Lord, who has two other children Niamh, 6, and Christy, 3, first thought that something might be wrong with Dylan when she prepared to take the family on holiday to Ireland in the summer of 2006. "Before I took him to Ireland, I took him to Lewisham hospital because he had a rash and they said that he had a virus but he'd be OK to fly," Lord says. "He was fine to begin with but by the end of the first week his temperature started to soar, so my mum and dad took him to Galway hospital. The staff there were quite concerned about him so I flew back with him and went to Lewisham hospital."
After a course of steroids that seemed, initially, to help, Dylan was allowed home. Lord's relief was short-lived, though, and within days Dylan's temperature was dangerously high.
"A couple of days later I took him back to hospital because his temperature was up to 40C. Great Ormond Street took him in but they had absolutely no idea what was wrong with him, which was just terrifying."
Dylan was tested for a variety of illnesses. After two months, the doctors looked at his genetic make-up and discovered that he had XLP and that he would need a bone marrow transplant. "I didn't have any idea what a bone marrow transplant was," Lord says.
Just as she was coming to terms with the fact that Dylan had a life-threatening illness, there was a second shock. Lord learnt that XLP was caused by a faulty X chromosome. "Dylan's condition only affects boys, so the doctors did checks on Christy. I found out a week later that Christy also had XLP. It was one of the worst times of my life."
Other members of Lord's family were then advised to have tests. "My sister has three boys and one girl, and luckily she's fine, but there are going to be other tests in the family to make sure they're OK."
XLP is extremely difficult to treat. Seventy per cent of people with the disorder die by the age of 10 if they don't receive any treatment. The best treatment is regular doses of antiviral medicines, immunoglobulin therapy, or steroids, but the only possible cure is a bone marrow transplant which, in effect, replaces the faulty immune system.
A critical factor in the success of a transplant is the accuracy of the match between the patient's cell tissue and the donor's, so finding a donor who matches a patient can be almost impossible. The Anthony Nolan bone marrow register is the most successful such register in the UK, and the third-largest register in the world. It was there that Lord began the search for matching donors for Dylan and Christy.
"The Anthony Nolan Trust has been a lifeline," she says. "They found a match very quickly. It's amazing that there are people out there who donate their bone marrow. I'm now a donor but there just aren't enough – there are thousands of patients awaiting bone marrow."
While donors were found for Dylan and Christy, Dylan's transplant went ahead first due to the seriousness of his condition. "Dylan went in for his bone marrow transplant in April. He had to have a huge dose of chemotherapy, which made his hair fall out and gave him mucositis, which meant that his mouth was covered in ulcers and his stomach was sore," Lord says. "Even though we were trying to make him better he was very, very poorly. Any kind of infection could have killed him."
After the transplant, Dylan was kept in a sterile environment to prevent him from catching any infection. But he developed graft-versus-host disease (GVHD), a life-threatening complication of a bone marrow transplant, in his lungs.
However, he surprised doctors with his tenacity and was eventually allowed home, where he spent six weeks with his family. "He seemed to be making really good progress," Lord says. "Then I took him in to hospital one Wednesday in July. I remember saying that he had a cough. By the Monday he was in intensive care in Great Ormond Street. He'd caught a common flu virus, which for anyone else would be like a cold, but it went straight to his lungs and his immune system couldn't fight it."
In spite of the fact that the bone marrow transplant had an 80 per cent chance of success, Dylan didn't make it. "He was very brave and I thought at one point he was going to make it, but he didn't," Lord says.
The loss has been hard for Dylan's young siblings to understand. But they think about their little brother all the time. "For what would have been Dylan's birthday last summer, Niamh came up with the idea of sending him balloons in heaven," Lord says. "She talks about him a lot. And the other day Christy said he wanted a big ladder so he could send it to heaven and Dylan could come back down.
"Knowing that Christy has to face the same battle is heartbreaking," she says. "He's such a happy little boy. His immune system is working at the moment because he hasn't got ill so nothing has triggered off a response in him. But certain things make him very vulnerable, like glandular fever – if he caught that, he could die. We've got to go down every step of that same road with Christy. It's so hard because he looks so healthy. With Dylan there was no option, but to see Christy running around and knowing that he's going to become so unwell because of the treatment is hard to live with."
Lord is now preparing to run the London Marathon with her father, Pat Barry. She hopes to raise awareness about XLP and about the importance of donating bone marrow, while Barry is raising funds for Great Ormond Street.
"XLP was discovered only 10 years ago, and it's thought the condition is underdiagnosed. It's very rare, but if your little boy becomes ill, it's certainly something to be aware of," she says. "I'm training for the marathon at the moment and this – as well as Christy and Niamh – has been what's kept me going. I hope Dylan would be proud of me – I've never run before now.
"Once the marathon's done, I'm going to carry on raising money for the Anthony Nolan Trust. I'm going to do a triathlon in August and a half-marathon in October. I want to keep Dylan alive by doing it – I don't want people to forget him."
Becoming a donor: the facts
* Bone marrow transplantation (BMT) is a form of therapy for patients with cancer or other diseases that affect the bone marrow.
* A bone marrow transplant involves taking cells that are normally found in the bone marrow (stem cells), filtering those cells, and giving them back either to the patient they were taken from or to another person.
* The goal of BMT is to transfuse healthy bone marrow cells into a person after their own unhealthy bone marrow has been eliminated.
* Matching donors and recipients involves typing human leukocyte antigen (HLA) tissue. The antigens on the surface of these special white blood cells determine the genetic make-up of a person's immune system. There are at least 100 HLA antigens. However, it is believed that there are a only few major antigens that determine whether a donor and recipient match. The others are considered "minor" and their effect on a successful transplant is less well defined.
* Would-be donors, who have to be 18 to 40 years old, have a full medical examination and receive counselling about the procedure before taking part. Accepted donors are admitted to hospital the day before the operation. They have a general anaesthetic, and the operation lasts one to two hours. The bone marrow is collected using a needle and syringe, with no cutting or stitching involved. Donors should be able to leave hospital 24 hours later.
* For more information about how to become a bone marrow donor, visit the website www.anthonynolan.org.uk.