Ironside: 'I was longing to know what my chances were of getting breast cancer (my mother died of it)'
A simple genetic test can predict your risk of getting cancer, heart disease or Alzheimer's. But do you really want to be told? Virginia Ironside took the plunge

Most people thought that I was bonkers to have a gene test that would show the medical conditions from which I was most at risk. Like ostriches, they put their heads in the sand. "Oh, we don't want to even think about the possibility of getting Alzheimer's or heart disease!" they said.

But I couldn't resist it. Knowledge is power, I said to myself as, feeling rather like Saddam Hussein, I wiped the insides of my cheeks with the little cotton-wool swabs on sticks sent to me by GeneticHealth, a company that offers a gene test to those who want to know what conditions they might be at most risk of. I was longing to know what my chances were of getting breast cancer (my mother died of it) or thrombosis (my father died of it), or Alzheimer's – no one in my family has ever suffered from it, but you never know.

Why? Because the whole point is that if you know what you're most at risk of contracting, then you can take steps to minimise the risk. If you find you're likely to get heart disease, say, you can spend your time swimming and jogging and eating a Mediterranean diet. If you've got the gene that says you might get thrombosis? Then you really do have to wear those dreadful pierrot-like stockings in planes, and make sure that you walk up and down the aisles. You can also stop smoking. Breast cancer? Get ahead, get a scan. The earlier it's caught, the better the prognosis. Osteoporosis? Have a bone scan and if your bones are crumbling, take supplements and hormones to combat it. Alzheimer's? You can take folic acid. Not only that, but once your memory starts to go just slightly, you can get your affairs in order and making sure that the person you want to have power of attorney gets it, rather than someone else.

Or, of course, while your mind is still clear, you can book a flight to Switzerland and sign on for Dignitas sooner rather than later.

Genetic testing is, no doubt, the coming thing. Even ITV1 has made a rather loopy documentary about it, called The Killer in Me, featuring four celebrities "unlocking the biological secrets within", to be shown on Thursday at 9pm.

GeneticHealth was started last year by two men – Brian Whitley, the managing director, and Dr Paul Jenkins, reader in endocrine oncology and honorary consultant physician at Barts and The London – Queen Mary's School of Medicine and Dentistry. What makes this outfit different to many other genetic-testing agencies is that they give you your results face to face, and don't, after your consultation, thrust a pile of expensive supplements on to you.

"What's good about genetic testing is that it is empowering," says Whitley. "When you know what you're at risk from, you can focus and think of your lifestyle. You're not at sea. OK, my father smoked every day, lived to 93 and died of pneumonia, but that doesn't mean I'm necessarily going to do the same.

"We've had some spectacular results. For instance, a fit man in his early fifties came to us, and because it was found that he was at high risk of heart attack, he was screened and had to have an immediate bypass operation. It probably saved his life."

Each parent gives a child a copy of the same gene. If each parent has pairs of good genes inherited from their parents, then the risk of getting certain illnesses and conditions is going to be slight. But let's say each parent has one good gene and one bad gene – they might pass on to you two bad genes, which means that your risks of ill-health in that area are much higher, even though your parents may have been problem-free.

Genetic testing can predict a good or bad menopause, and there are certain gene variations that can make you many times more likely to develop certain cancers – there's one variation that can make you 140 times more likely to develop lung cancer if you're a smoker. If a woman has the faulty version of the BRCA1 gene, there is an 85 per cent chance she'll get breast cancer and a 40 per cent chance she'll get ovarian cancer (though it should be said that if you have good reason to suspect that you have this faulty gene, your GP can arrange a test for it).

The big one is, of course, Alzheimer's. Since there is very little you can do about it if you find that you have the "4" variant of the ApoE gene, which predicts a 400 per cent increase in the risk of getting Alzheimer's disease, GeneticHealth insists that people sign a special document if they want the results to be included. Surprisingly, nearly everyone wants to be told.

There are two areas that the move towards genetic testing will affect drastically. One is insurance. If you have the test done privately and ask for it not to be sent to your GP, there is no reason why you shouldn't, if you discover your health risks are very high in certain areas, get yourself insured for "critical" or "chronic" health insurance. On the downside, there might come a day when medical insurance companies actually demand that clients have gene tests in order to be able to deny them treatment for illnesses that they are particularly likely to get.

The other implication is in the area of drugs. Gene testing can tell you how likely you are to metabolise drugs slowly or quickly. This also determines how prone to side effects you might be, and affects the dosage a doctor gives you. If you are a slow metaboliser, the drug stays in your blood longer, with more side effects, so doctors could prescribe lower doses. For people with a high metabolic rate, the dose might need to be higher.

There are also some drugs to which many people won't respond at all. "With the answers given by genetic testing, you might be able to save yourself, say, six courses of debilitating chemotherapy," says Whitley. "The cost of useless drug therapy is enormous, and genetic testing means it can be reduced hugely. The NHS could save thousands of pounds just with a DNA swab."

I imagined that most of the people applying to have a gene test would be hypochondriacs and the worried well, but far from it. "Five years ago, 50 per cent of people wouldn't want to know," says Whitley. "Now, it's more like 20 per cent. People know that the information is available and they demand to know.

"We thought that our clientele would consist mainly of women between 35 and 45, but in fact, it has mostly been men and women over the age of 50."

One person who has taken the test is Dr Chris Steele of TV's This Morning programme. "I thought, 'I've got to catch these guys out. I won't tell them the truth in my medical history beforehand'. So I said that I had low blood pressure when I had high blood pressure. But when the results came, they showed that I was at high risk of high blood pressure. I couldn't fool them. It also turned out that I was high risk for cancer. As I've had skin cancer twice, it all fits in."

Genetic testing appeals particularly to those who are adopted and know nothing of their genetic history. Alison Sanders' (not her real name) mother was killed in a car crash when Alison was one, and her father was killed in the war. "I had no idea what they would have died of had they lived," she says, "and I was adopted as a baby. My husband has died and I don't have any children, so I thought I must prepare for the future.

"The results were very good – the only thing the test showed was a risk of osteoporosis, but I already knew I was borderline. which made the test more believable. I felt so relieved when I'd had it done – you know you're going along the right track."

A clinical psychologist of 51, who didn't want to give her name, said: "The most important thing for me to come out of the test was the fact that I have a genetic disposition to osteoporosis. Dr Jenkins suggested that I take a calcium supplement and ask my GP for a bone scan, and he encouraged me to get back to the gym.

"More specifically, it showed that I have a rare genotype that causes increased levels of homocysteine in the blood, resulting in arteriosclerosis. I now take folic acid, which negates this risk. I wish I'd known earlier, but finding it out now is hopefully protecting me to some extent. I felt absolutely delighted. These two things were always knocking around in my head, and now I know I feel more in charge."

My own results? I was both surprised at them, and at my reaction to them. Having thought that I couldn't care less about the verdict, I was amazed to feel a great wave of relief and, almost, joy. It turned out that the only thing I was at risk from was high blood pressure, and as I have the blood pressure of a lizard (ie very low), I have nothing to worry about. My only anxiety now is whether I am going to die of anything at all.

At the moment, gene testing is expensive – £825 for the full works. But that is sure to go down drastically when health services realise how much they can save by using it preventatively. "And anyway," says Brian Whitley, "we often spend more over the years having our cars serviced. Yet we never think of looking under our own bonnets, as it were."

How the test works

You take a swab from the inside of your cheek, and send it off, together with a form detailing your medical history. An individual report is then prepared, which can be emailed to you, though it is suggested that you visit a doctor to discuss your results.

GeneticHealth tests for risk of the following conditions:

* Cardiovascular disease

* Breast and ovarian cancer risk (for women)

* Prostate cancer (for men)

* Thrombosis

* Hypertension

* Metabolism and obesity problems

* Prescription drug reactions

* Homocysteine

* Hormone replacement problems

* Osteoporosis

* Alzheimer's disease (optional)

GeneticHealth: 0870 043 5551;