Steve Jones - The Language of the Genes

Genetics raises interesting questions. Should an insurer have the right to demand the results of a test to help them decide the price or whether to offer cover at all? Is a damaged gene a "pre-existing condition"? After all, everyone must die; and DNA does no more than tell some (and, in years to come, perhaps most) people when that might happen. But, as insurance depends on spreading risk, genetics may be a terminal blow. It erodes our ignorance of the future. No-one will play with a gambler who knows his opponent's cards and no-one will pay for cover when they are certain that they will live to a ripe old age (and will not need it). The same may be true when the insurers know thar an expensive illness is programmed into the genes. Insurance already suffers because people at high risk.ire more likely to buy a policy. Genetics might spark off a war of cost escalation that ends with only the risk-prone paying for medical insurance.

Already, the companies refuse to cover those doomed to Huntington's Disease and other ailments. Denying cover is no empty threat. A woman in charge of a fragile X screening programme in the United States was refused insurance because her children had symptoms although she had none. In another case, the insurer agreed to pay for a foetus to be tested for cystic fibrosis — but only if the parents agreed to have an abortion if the test was positive.

A commercial health market sees good and bad buys and an employer who pays the bill faces pressure not to hire someone who may be in jeopardy. All this is an argument for a national service which diffuses risk among the whole population. Then health care will revert to the role of a policeman rather than a security-guard, with an acceptance that all must pay, even if some are in more danger than others.

Public health, like insurance, also involves a balance between individual rights and social obligations. Why, after all, is it no longer acceptable to spit in the street; and why do smokers regard themselves as a persecuted minority? Perhaps to screen a new-born child, or an adult, for its inborn weaknesses will come to be seen as a duty both to the person involved and to the social order rather than a mere commercial transaction. Already, every infant, with or without the knowledge of its parents, is checked for whether it carries a range of genetic diseases, PKU being only one.

There are plenty of cases in which this could be useful. Hemochromatosis is a recessive condition that leads to a failure to cope with iron in the food. Untreated, it may be fatal, with damage to heart and liver. About one European in four hundred is born with the disease, and it is even commoner among those of African ancestry. Hundreds of thousands of Britons are in danger (with men at five times the risk of women). The gene has been found and most patients carry one of two mutations. Treatment is cheap and simple. A vessel is opened to lose blood and to prevent the build-up of iron; medical wits have it that patients should grow roses as blood is such a good fertiliser. A simple scan early in life could save many lives and save much expense involved in the treatment of those to whom the damage has already been done.

Medicine has also succeeded in treating genetic diseases that once killed young. The main concern of the eugenics movement was the biological future. Sterilisation was an easy way to reverse what they saw to be undesirable trends. The new biology hopes to become a positive force rather than a mere filter for the imperfect. Cystic fibrosis is lethal because the lungs fill with mucus, and because certain digestive enzymes cannot be made. Conventional medicine — careful treatment of the lung problem, and the use of an enzyme that helps break down mucus — has increased both the quality and the length of life of those with the disease. For some patients a heart-lung transplant can help.

Such successes mean that medicine has already altered the genes of years to come, for many of those who once would have died of cystic fibrosis and other diseases can now be saved to pass on their faulty DNA. Opticians, too, have played a part. A short-sighted hunter-gatherer may well have starved, but the invention of spectacles removed the penalty attached to any genes involved and they have gained as a result. Only if spectacles were banned would that en use problems. Any success in treating inborn disease causes the gene to become commoner in later generations; but as long as medical treatments remain available that will have little practical impact.

Whatever these local triumphs, the biggest problem of modern genetics is one that the public has scarcely realised; the ubiquity of inborn disease. About one child in thirty in Britain is born with an overt genetic problem of some kind and inborn illness causes about a fifth of infant deaths. Over a third of blind people face their plight for genetic reasons and more and more illnesses have been revealed to have an inherited component. In some places the problem is even greater. Around the Mediterranean and in Africa errors in red blood cells, which evolved to protect against malaria, affect millions. Cyprus has many genes for various forms of thalassaemia, loss of a segment of the haemoglobin molecule. Any child born with two copies suffers from severe anaemia. The treatment is blood transfusion, which works but is so expensive that to treat all affected children might soon soak up half the health budget. One person in fifteen, worldwide, is a carrier of one of the malaria resistance genes. Without a medical breakthrough no society will be able to treat the millions of anaemic children who will be born unless something is done to reduce their number. High cost will mean hard choices.

Most genetic technology is simple: to identify a damaged gene and offer the choice of therapeutic abortion. AH the common defects can be detected in this way and many more have the prospect of a test. But, as the screens become more sophisticated, where should the line be drawn? In Russia pregnancies have been terminated because the foetus is thought to carry genes that dispose to diabetes. But diabetes is a disease that can sometimes be treated with insulin. And what about diseases for which no treatment is yet available, but might be curable by the time the child is in danger of dying? In muscular dystrophy, for example, we now know what protein has gone wrong and a normal version can help mice with a gene for a similar condition. It is not impossible that some treatment may be available within the next couple of decades. As many boys born now with the disease are likely to live as long this poses a moral dilemma of its own. For pre-natal diagnosis, the equation is affected by the age of parents (and hence the mutation rate), how related they are, any family history of inherited disease, the severity of symptoms, the possibility of treatment, and attitudes to abortion. All this make the process more and more ambiguous.

Decisions based on appraisals of inborn quality;uc not new but now, for the first time, may be accurate. Should damaged genes be allowed to pass to the next generation, or should the human race attempt to enhance its quality in some way? There are each year, worldwide, about ninety million births and sixty million induced abortions. Britain alone in 1998 had a hundred and eighty thousand abortions, only two thousand of which were on grounds of abnormality. Many more pregnancies end without the woman knowing of her condition, often because the foetus has a severe genetic defect. Even more eggs are lost. A baby girl has a million or so in her ovaries. Three quarters disappear before puberty, and at the age of twenty five she loses, on average, forty or so a day while producing only one a month. The waste of sperm is even more prodigious and, for either sex, many of the sex cells are doomed because of their biological weakness. Genetic selection is a natural part of reproduction. Even so, attempts to choose sperm or eggs or to change the balance between uncompleted and completed pregnancies lead to bitter controversy. Some demand that the state control reproductive choices but others feel that such decisions must be the parents' alone.