The growing danger from gene-spliced hormones

My son Peter is twelve, and lately the cuffs of his pants have been racing up his ankles -- a sure sign that growth hormone is coursing through his body. He's on about the same growth schedule I was. By my fourteenth birthday I was already just shy of six feet, and hopeful of four or five inches more. I thought that would be enough to give me a shot at playing basketball in college. Alas, I'd reached my limit. Lacking any notable physical talents, I had to rely on guile; if you can't shoot over the guy, get him looking one way and then scurry past on the other side. (As we used to say, ''Fake left, go right.'') Recent happenings in genetic engineering make me wonder if something similar, albeit unintentional, is going on there: Is our attention being directed one way while what's important is slipping by on the other side?

At least since 1980, worries about using recombinant DNA technology to alter ''human nature'' have focused on gene therapy -- the direct and intentional alteration of genetic material to treat disease. On June 20 of that year the general secretaries of three national organizations, for Protestants, Jews, and Catholics, wrote the President to warn: ''History has shown us that there will always be those who believe it appropriate to 'correct' our mental and social structures by genetic means, so as to fit their vision of humanity. This becomes more dangerous when the basic tools to do so are finally at hand. Those who would play God will be tempted as never before.''

Nothing garners attention as quickly as a nice little scandal; within a month of the letter, Dr. Martin Cline of UCLA provided one by experimenting on two patients with beta-zero thalassemia, a genetic condition that causes severe anemia. Cline removed some of their bone marrow, treated it with recombinant DNA containing normal hemoglobin genes, then reinserted it into the bone (after making room by killing some of the remaining marrow cells with radiation). The hope was that the treated cells would multiply and produce normal hemoglobin.

They didn't. Worse, Cline didn't have the approval of the UCLA committee that oversees research with human subjects. When the affair became public, the National Institutes of Health (NIH) stripped Cline of $162,000 in grant money and demanded strict supervision of his research. For those suspicious of human gene therapy, the case was proof that scientists couldn't be trusted to regulate themselves.

Since then, such work has proceeded very cautiously. A presidential commission gave its tentative blessing to gene therapy with somatic cells -- those that don't pass the altered genes on to future generations. The NIH's watchdog recombinant DNA advisory committee set up a ''human gene therapy subcommittee,'' which has suggested ''points to consider'' for doctors who propose to tinker with genes. Among them: whether the benefits of the treatment outweigh the risks, how to choose patients fairly, and how to publicize the results of the research. Thanks to the brouhaha over gene therapy, no great threats to humanity are likely to slip by in the near future -- at least not on that side.

But there's another side to genetic engineering that has the power to alter us physically and socially. Rather than directly altering our genes, it can mod- ify our bodies by supplementing the natural supply of important regulatory hormones with genetically engineered ones. A prime example is biosyntheti- cally manufactured human growth hormone -- hGH. Except for one additional amino acid -- methionine (which appears to have no effect on its action) -- biosynthetic hGH is identical to the hormone that promotes normal growth.

Produced in the pituitary gland, hGH plays a key role in determining how tall we'll become. So-called pituitary dwarfs usually lack an adequate supply of bioactive hGH. To treat them, for more than twenty years we've been harvesting pituitaries from human cadavers, each of which yields a minute quantity of hGH. Until recently the supply was barely adequate. In 1979 genetic engineers cloned the gene carrying instructions for making hGH, inserted it into a microorganism, and coaxed the bug to produce the human hormone. Just in time, it appears, because some hGH recovered from human pituitaries seems to have been contaminated with the slow virus that causes Creutzfeldt-Jakob disease (CJD), a degenerative infection of the brain. In April 1985 the Food and Drug Administration (FDA) halted the sale of natural growth hormone, and shortly thereafter approved Genentech's biosynthetic version. Since no human tissue is used in producing it, there's no danger of contamination with the CJD virus. Also, we're no longer limited by the scarcity of cadaver pituitaries, and other uses for hGH can be explored.

Biotechnology came to the rescue of kids deficient in growth hormone. But if hGH injections can make extremely short children a bit taller, what can it do for those who aren't dwarfs, but just shorter than average? What about the youngster who would have been only of average height? And what about the basketball player for whom a couple of inches more might mean the difference between the schoolyard and the NBA? In short (no pun intended), why not use hGH to give your child the advantages that come with being tall?