The family of a teenager with a rare metabolic condition has welcomed news that blood tests for the disease are to be offered to newborn babies across England.

Katy Frost had no idea she had the potentially fatal Medium Chain Acyl CoA Dehydrogenase Deficiency (MCADD) until she collapsed on holiday at the age of ten.

Her organs had started failing and her parents were told to prepare themselves for the worst.

Fortunately medics were able to diagnose Katy's illness and she was given the treatment she needed to recover.

Now, 13, Katy is doing well and a pupil at Oathall Community College in Haywards Heath.

MCADD affects the body's ability to break down fat for energy, especially when someone is ill or has not eaten for several hours.

Those with the condition can become seriously ill and even die unless they are given glucose.

The new screening programme aims to prevent a crisis ever happening by diagnosing the condition through the routine test when a baby is around five days old.

Katy's mother Cora Durkan, 46, from Haywards Heath, said: “We were lucky that she survived.

“MCADD can kill. However easy it is to manage, when it goes wrong, you can die.”

Katy was on a school activity holiday on the Isle of Wight in July 2005 when she fell ill.

Ms Durkan, a hospital administrator, got a call saying teachers were going to have to take her to hospital because she wouldn't wake up.

She did not panic at first because she thought Katy was dehydrated after an active day and she had noticed previously her daughter could be drowsy after being sick but soon perked up after a drink or sugary snack.

However Katy was then taken to the intensive care unit at Southampton Hospital and Ms Durkan and Katy's father, Joe Frost, who lives in London, raced to her side.

Katy had to be shocked with a defibrillator 14 times and her brain started to swell.

Ms Durkan said: “They said she had brain damage. Her eyes were fixed with dilated pupils. She looked dead basically. I really did think she was dead.”

The breakthrough came when a doctor suspected a metabolic problem and rang other hospitals for advice.

Once MCADD was diagnosed, the toxic build-up in Katy's body was dealt with and her glucose replaced.

Katy, who remembers very little about the experience, spent two months in hospital before she was transferred to the Royal Sussex County Hospital in Brighton.

She said: “MCADD doesn't have a dramatic effect on my life. It's a little hard but it could be much worse.

“I sometimes forget I have it.

“It's usually when I'm feeling ill that everyone goes and brings out the Mars bars and Ribena.

“The routine tests for babies is a good idea because otherwise some people could find out like me.”

Ms Durkan said: “If we had known that she had it, the MCADD crisis obviously wouldn't have happened.

“That's not an experience I would wish on anybody and it's very scary.”