By ISLA WHITCROFT

Last updated at 00:16 16 May 2007

To the casual observer, there was nothing unusual about Sophie Perren's birthday party last weekend. Surrounded by her relations and 12 of her friends, the eight-year-old celebrated the occasion at a local family pub with face painting, dancing and party fare.

But for her mother Nancy, 42, the pleasure of the party was marred by the knowledge that letting Sophie mix with other children could put her life at risk.

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Sophie suffers from the rare immune system disorder, cyclical neutropenia, which means that not only is she more prone to infections generally, but every two to three weeks she is at serious risk of catching an infection she will be unable to fight.

She has already suffered two bouts of pneumonia, four of septicaemia, numerous throat, ear and chest infections as well as a respiratory virus similar to Sars. She has been hospitalised more than 100 times, resuscitated at least 30 times and been given countless courses of antibiotics.

When Sophie was a baby, her mother assiduously followed doctors' instructions to keep her daughter in a totally sterile environment at home. Anyone who came to the house had to scrub their hands with disinfectant, and every eating utensil, toy and surface Sophie was likely to touch was likewise sterilised.

Sophie was unable to go to nursery school or play with other children. It is every parent's instinct to want to protect their child's life, but Nancy has now taken the difficult decision to remove her daughter from this cocooned world.

'Sophie had to have some quality of life,' says Nancy. 'I adore her and have fought for her almost her entire life. But I know that I have to swallow my fears and let her live a little - even if it makes her ill.'

When Sophie was born, she was an easy baby, says her mother. 'She was beautiful, with lovely long lashes and gorgeous big blue eyes. Her older brothers, Danny, now 24, Jason, 22, and sister Kirsty, 16, adored her.

'For a few short weeks we were blissfully happy. Then one day, when she was about eight weeks' old, she became slightly constipated. The next morning I woke up to hear her making grunting noises.'

Nancy adds: 'When I picked her up from her cot next to me, she was listless and I could see from her expression she was very uncomfortable.

'I made an appointment with the GP for that afternoon but by 11am she was screaming in pain and felt very hot. Then her skin became a mottled texture with purple ridges. That was enough for me.'

Nancy went straight to the surgery and begged to see her GP immediately. The receptionist took one look at Sophie and ran to get the doctor.

Sophie was rushed to the local hospital, North Tees General, where a team of doctors were waiting. 'By now Sophie's hands and feet were freezing cold and her lips and eyelids purple,' says Nancy.

The fear was meningitis, but a lumbar puncture and blood tests - which left Sophie screaming - proved negative. Instead, she was diagnosed with a bacterial virus. She bounced back and five days later was discharged from hospital.

Two days later, Sophie was asleep when some sixth sense made Nancy come in from the garden to check on her. 'As I walked towards the crib, I could see something was terribly wrong,' says Nancy.

'Sophie was purple and limp and she'd stopped breathing.'

Her screams brought Sophie's father Simon and brother Danny, then 17, running. All three were too inexperienced to attempt resuscitation. But within five minutes an ambulance crew arrived and got Sophie breathing again and took her to hospital. But less than five minutes away, Sophie stopped breathing again.

As the blue lights flashed and the sirens wailed, the paramedics kept her alive with mouth-to-mouth resuscitation. It took doctors 45 minutes to get Sophie breathing for herself.

Sophie was diagnosed with septicaemia and given huge quantities of antibiotics. Doctors also ordered scans to check if she had suffered any brain damage. Every test came back clear and the doctors - and Nancy - put the two episodes down to bad luck. Sophie was discharged.

Three weeks later, Nancy heard her grunting and saw that her eyelids were going blue. Recognising the signs, Nancy rushed her to hospital.

Sophie was diagnosed with an acute ear infection and once the symptoms had gone, was discharged five days later. 'Again we simply thought it was bad luck,' says Nancy.

But as a precaution the family, including Kirsty, then eight, were taught resuscitation techniques. Just four weeks later, they needed them. Nancy, who had taken to cat napping beside her daughter's cot, was woken by soft grunting sounds. She could see that, once again, Sophie was no longer breathing.

'I picked her up and ran with her out on to the landing, laid her on the floor and started mouth-to-mouth,' she said.

'In between, I was dialling 999 on my mobile and Kirsty came out of her room and started screaming with terror.'

Back in hospital, the diagnosis was a throat infection but by now the doctors were searching for other underlying conditions.

When Sophie was about eight months' old, the doctors were agreed that she had some sort of immunity problem, although it wasn't clear what exactly, because her white blood cell count remained normal in-between her illnesses.

Two months later, a consultant explained to Nancy that she thought Sophie had cyclical neutropenia. 'When I asked her whether it was fatal she looked away and said "possibly". I felt like passing out,' recalls Nancy.

Cyclical neutropenia is one of the rarest forms of neutropenia. Here the bone marrow stops producing neutrophils approximately every 21 days and during that time the child is unable to fight any infection.

It is incredibly difficult to diagnose because most of the time the child's neurtrophil reading would be normal.

'The consultant explained that the only way of diagnosing the disease was by doing blood tests twice a week for six weeks,' says Nancy.

'This would monitor the white blood count over two possible neutropenic cycles and we would then know for certain.' The tests confirmed it.

Neutropenic children are always at risk of infection, some more than others. But Sophie's case is quite severe and what would be a safe level of risk for other children could kill her.

'If she had an open wound or even a scratch, and she was touched by someone with bacteria on their hands she could be overwhelmed by that bacteria within hours,' says Nancy.

In the course of her research, Nancy came across the story of a girl who'd managed to live with the condition for 21 years, but who'd then drunk from a dirty cup - and within hours was dead. It was a terrifying and overwhelming prospect.

'I was reading medical information on my bed one day and became so overcome with grief I slid off the bed and lay on the floor crying,' says Nancy.

Sophie was put on a constant dose of the antibiotic Septrin to protect her as much as possible. Nancy was also told that she had to live, as much as possible, in a sterile environment. Her siblings had to wash their hands constantly as did anyone who came to the house.

'I went to the chemists' and bought bottles of sterilising fluid and went home to scrub every room in the house,' says Nancy. 'We got into a routine of cleanliness which soon become second nature. Sometimes it felt as if I had my hands permanently in hot water.'

Sophie couldn't go to nursery and if she went to the park it was when there were no other children about.

'We filled her time with drawings and music, pottering in the garden, playing with her toys and watching videos.

'But it was hard for Sophie and for my other children. Jason was supposed to be taking his GCSEs, but he was determined to spend as much time as possible with us at the hospital and in the end he left school at 16 without taking any. I still feel guilty about that.

'Kirsty was getting to the age where she wanted to have friends round for girly sleepovers, but because of Sophie's condition it just wasn't possible.'

'I think for a good couple of years we were all living under a dark cloud. The bottom line was that we were terrified of losing Sophie. Simon and I had already split up before Sophie's illness was diagnosed, so I was the main carer.'

The antibiotics and the sterile environment seemed to work. Although Sophie continued to contract infections, they were not nearly so rapid or severe, although she was always hospitalised.

But as she grew from babyhood and reached the age of two and half, Sophie started to ask why she couldn't play with other children.

'We explained to her that she could catch bugs from other children which might kill her. She was quite accepting and I used to hear her talking to her brothers and sister about it.

'But I could see that as she grew older the situation would become more difficult. I felt too, that she was getting stronger and the attacks were less severe and so, when she was two and half, I made a difficult decision.

'I weighed up the risk of her contracting infections against the poor quality of life she was living and after much agonising, decided that we had to let her spread her wings. So I enrolled her in a kindergarten.

'Her doctors weren't too happy but Sophie just loved being with other children. Of course, it was difficult especially for the staff who had to keep Sophie as hygienic as possible, but we managed.'

Then, when she was three, disaster struck. Within a few short hours she went from normal to comatose and by the time Nancy got her to hospital it was clear this was something more serious than usual.

Her oxygen levels were low and the doctors were unable to get her to breathe unaided.

'An X-ray showed she had pneumonia in her left lung,' says Nancy. 'She was unconscious for 12 hours, but then she woke up and demanded gravy and mashed potato.'

However, this time there were more serious repercussions. The damage caused to her lungs and airways by the bacterial infection left Sophie with severe asthma, which plagues her to this day. It also meant that any more bouts of pneumonia would be even more dangerous.

Then last March Nancy went to pick Sophie up from school and found her pale, rocking on her heels, hardly able to stand. Her teachers had been frantically trying to call Nancy but, for once, had been unable to contact her.

She was rushed to hospital. Within a few minutes of arrival she was drifting in and out of consciousness and oxygen levels were plummeting.

As the doctors took blood, called for X-rays and hooked Sophie up to drips and wires, Nancy lay her cheek against her daughter's face.

'I whispered: "Don't leave me Sophie",' remembers Nancy, fighting to hold back the tears. 'Sophie asked: "Am I going to die, Mummy?" and I said "Not if I have anything to do with it".'

Sophie managed a little smile and an 'I love you' before her eyes closed again. Sophie had acute double pneumonia, one lung had collapsed completely.

'After years of fighting infections, countless resuscitations and miraculous recoveries, it felt like the final goodbye and I wasn't sure I could bear it.'

Five and half 'long' days later doctors removed her ventilator in the hope that she would breathe by herself.

'I couldn't bear to watch so I stood on the other side of the curtain,' says Nancy. 'Suddenly, I heard a cross little voice calling "Mummy" and I ran round and pushed the doctors out of my way in my eagerness to hold her.

'The next thing she said was "Where's Danny?" and my oldest son came in with tears flooding down his cheeks.

'Many people think we have been unlucky, but Sophie can walk, talk, dance, go to school and have fun,' says Nancy. 'Lots of parents would settle for just one of those things.'

Sophie's doctors do have one more card up their sleeves: she could be considered for G-CSF, a treatment to stimulate the production of white blood cells. However, there are side effects and it is not a cure, but simply eases the condition. It is seen as a last resort.

'The past seven years have been incredibly tough,' says Nancy. 'And I would be fooling myself if we didn't think there will be hard times ahead.

'But I consider every day I have had with my lovely daughter to be a gift. She has made us happy.'