25 June 2010 Last updated at 04:02 ET

Jenny Agutter: 'Cystic fibrosis is in my family'

By Neil Bowdler Health reporter, BBC News

The actress is a carrier of the mutated CF gene

Jenny Agutter carries a hereditary gene flaw that no one in her family knew about.

It was only after her niece Rachel was diagnosed with cystic fibrosis that she discovered she carried the mutated gene which can cause the disease.

"The first I knew about cystic fibrosis was when my brother rang having discovered that his daughter, his first child, had CF," she says.

"When she was born he was absolutely delighted, they were both over the moon. And then they went through three or four months of seeing her struggle to survive."

Longer life

Survive she did. Indeed, her aunt describes her as an energetic party-goer.

"The median age to which people lived at that time was nine years. Now they talk about the median age as being 30.

"My niece is now 31. She has to work hard on her health, but she is terrific."

That does not mean that life has been simple.

"My niece has been in and out of hospital but I think what the most scary time is when suddenly a CF sufferer does actually grow up and is suddenly in charge of their own life."

A bout of illness before Rachel started university threatened to derail her plans, but she pushed on through and now works as a photo researcher for a magazine, "a job she loves".

Family secret

Jenny decided to have herself tested for CF when she became pregnant with her son 20 years ago.

The test revealed that, like her brother she was also a carrier of a faulty version of the cystic fibrosis transmembrane conductance regulator gene (CFTR), which causes CF.

But a test of her husband revealed he didn't carry the mutated gene, which meant their children would not be at risk.

"It takes two people with the one single gene to create this problem with CF, so my brother is a carrier and his wife is a carrier, and it turns out I'm also a carrier."

The discovery has also left her wondering whether both her parents were carriers. The fact they lost two children soon after birth with complications resembling those associated with CF, makes her think that the babies probably did have the disease.

Gene hope

Jenny is now actively engaged in her work as a a patron and trustee of the Cystic Fibrosis Trust. She is optimistic for the prospects for sufferers, buoyed not least by the impact better treatment and medication has had on the number of years those with CF can now expect to live.

But she believes much more can still be done, and is hoping gene therapy could bring a breakthrough.

CYSTIC FIBROSIS

• Cystic Fibrosis (CF) is one of the UK's most common life-threatening inherited diseases
• Cystic Fibrosis affects over 8,500 people in the UK
• Over two million people in the UK carry the faulty gene that causes Cystic Fibrosis - around 1 in 25 of the population
• If two carriers have a child, the baby has a 1 in 4 chance of having Cystic Fibrosis
• Cystic Fibrosis affects the internal organs, especially the lungs and digestive system, by clogging them with thick sticky mucus
• Each week, five babies are born with Cystic Fibrosis
• Around half of the CF population can expect to live over 38 years, although improvements in treatments mean a baby born today could expect to live longer

Source: Cystic Fibrosis Trust

"The very exciting thing right now is that they are looking at changing the make up of the lung with gene therapy," she says.

"Most people who who have CF die with lung disease - about 90%. So if you can keep the lung healthy you can basically create an ordinary life for the CF sufferer."

The ultimate aim, she says, must be a full life without fear.

"[Rachel] lives day to day as does anyone with CF. They don't know what is going to happen.

"If they get ill it can be a virus that will just kill them and that can happen at any time, and that is very difficult for any family to live with."

"I would love the possibility that people would live without this life threat. It makes a big difference to the way you live."

The diagram shows how CF is inherited. Where both parents carry the faulty gene, each child has a one in four chance of having CF, a two in four chance of being a carrier and a one in four chance of not having any CF genes