Science: Is genetic disease fair game for insurers?

Will testing lead to unfair discrimination against those with a genetic defect?

A MAJOR cause of anxiety about genetic testing is the effect it will have on life insurance. Is there not a danger that those people who have a genetic disposition to a disease will have greater difficulty getting life insurance, or be charged excessive premiums? Will such testing not lead to grossly unfair discrimination against those with a genetic defect?

The Government's Human Genetics Advisory Committee considered this a few years ago, and though it did not foresee serious problems, a Genetics and Insurance Committee was set up to provide independent evaluation of the use of genetic evidence in setting insurance premiums. This committee is there to ensure that the science used to fix premiums is sound. But does that remove the fears of unfair discrimination for a genetic disposition for which the individual has no responsibility?

Insurance can be promoted as a way of doing the most good for the most people while still allowing the insurance companies to make an attractive return on their investment. It is a competitive business and may, in some ways, be likened to gambling - the insurers are betting that they know how many are going to get ill and die, and when. While wishing to insure as many as possible, there are some who will not qualify as they may, for example, already be too ill.

Do companies, in fact, make use of genetic tests? The Association of British Insurers, to which almost all insurers belong, has specified a code of practice which lays down that they will not ask for a genetic test to be done, but - and this is a big but - they will want to know the results of any genetic test that has already been carried out. What use will they make of it, and how new is the use of genetics in insurance?

Insurance companies have for a long time made use of genetics by requiring information about diseases that have affected other members of the family, particularly, of course, the parents. The best-studied example is Huntington's disease. This is caused by a single faulty gene and if one of the parents has the disease there is a 50/50 chance of a child inheriting the same illness. The first signs of this disabling disease usually appear only between the ages of 30 and 50, and death follows within about 10 to 20 years. It is a rare disease - about one in 20,000 get it. It should not worry insurers as its effect on the insurance world as a whole will be minimal, but it could affect a single company if there were many Huntington's sufferers on its books.

It is possible to test the DNA of individuals who may have Huntington's disease and unequivocally find out whether or not they have it. Whether to have the test is a difficult decision, now made more difficult if people want life insurance. If they test negative, all is well and the premium will be a normal one, but if they test positive then it may be difficult to get insurance and the premium may be many times higher; legally they must disclose the result. If they do not have the test the insurance company will not ask for it to be done, and some insurers will insure them at a rate more than the normal, but not intolerably so. This possibility of insuring people suspected of developing Huntington's, even if they have not had the DNA test, has come from a mathematical model of the course of the disease based on more than 1,000 patients from Holland.

Huntington's disease is simple compared to other disorders such as heart disease and cancer, where many genes may be be involved in increasing the susceptibility. Knowing an individual's DNA in detail may give a rather poor prediction of what illnesses may develop in later life. We may even ask whether this new information is significantly superior to knowing the family history.

So, at the moment, genetic testing does not seem to raise serious issues. What has to be avoided is the situation that has arisen in the US, where an insurance company has insisted that a mother terminate her pregnancy when the foetus has been found to have a debilitating illness; if she does not do so, then they will refuse to cover the child's health costs after it is born.

The writer is professor of biology as applied to medicine at University College London