Table of Contents | Glossary
Dr. Lu's Patients Have
the Right to Be Tall
(or do they?)
Dr. Lu has two patients with the same problem, but she isn't sure if she should treat them both. The patients, Tim and Rico, are seven-year-old boys who are very short for their age.
Tim will never grow much taller than 5 feet because his body does not produce enough of a hormone needed to grow. When he is an adult, Tim will be much shorter than his mother and father, who are both closer to 6 feet.
Rico will never grow much taller than 5 feet either. Rico will be short because he has inherited his body build from his parents, who are both about five feet tall.
Researchers have used genetic engineering to produce a growth hormone. Both sets of parents want this growth hormone to be prescribed for their sons to help them grow taller. They want this because they feel that there are many advantages to being tall.
Dr. Lu realizes that genes play a role in the height each child will reach. Tim will be short because of a single mutation in one gene that instructs for the production of a growth hormone. Rico will be short due to the many genes he inherited from two short parents. Despite this difference, the end result for both boys will be the same.
Dr. Lu is thinking about prescribing the hormone for Tim, but not for Rico. However, she wonders if she is being fair. If you were Dr. Lu, what would you do?
When you fall ill, you sometimes need to go to a doctor to find out what is wrong. At the doctor's office, they will observe your symptoms and examine your body. They may look inside you using X rays and other equipment. They may do tests on your blood or urine, to see whether anything is wrong with your cells or the way your body is working. They also may do something else: look inside your cells at your genes. Every day, genetic research is being applied in new ways to help diagnose health problems.
Someday, it also may be possible to correct health problems by going inside cells to the genes. Treating disorders by altering genes is called gene therapy. It will work something like this. When you have an illness, your doctor will determine whether the problem is caused by a mutated gene that is giving out faulty instructions for the production of a needed protein. If so, new DNA will be inserted into some of your cells. This new DNA will correct the gene's instruction for making the protein. If the treatment is successful, the repaired gene in these cells will go to work, giving out the proper instructions so that the protein is produced.
Cystic fibrosis is one disease that researchers are trying to cure through gene therapy. In Chapter 4, we explained that with CF the lungs become clogged, making it hard to breathe. The problem is caused when a gene gives faulty instructions for producing the protein that helps make the mucus lining of the lungs.
Doctors are trying to move corrected copies of this gene into the lung cells of CF patients, using a virus. We usually think of a virus as causing illness. However, the kind of virus used in this experiment is harmless. Using special techniques, copies of the corrected gene are inserted into the virus. Then the virus is sprayed up the nostrils of the patients. The virus attaches to cells inside the nose and lungs and reproduces by inserting part of itself into them. As it inserts its DNA into these cells, it also inserts the corrected gene. Hopefully, the corrected gene will take over in enough cells so that the needed protein is produced.
Gene therapy is also being tried with a disorder called severe combined immunodeficiency (SCID). This disorder occurs when the body fails to produce a particular enzyme. Without the enzyme, a person cannot make the special blood cells that resist infection. A few young children with this disorder have been treated with cells altered to carry the genetic instructions for making the enzyme.
It is too early to tell whether these treatments will work. Hundreds of research trials are under way using gene therapy. None has yet been able to claim complete success, although a lot of valuable things are being learned. Even so, gene therapy is still so experimental, that it is being tried only on patients who have diseases for which there are no other cures.
It's also important to realize that gene therapy may never work for a wide range of health problems. It may be too difficult to use genetic therapy for disorders that involve the actions of many genes. Also, for many health problems in which genes are involved, the genes are only partly responsible for what's wrong. In such cases, gene therapy may be only part of the solution. Gene therapy also may be of little use in treating medical problems that have no genetic cause, such as broken bones or wounds caused by an accident.
The kind of gene therapy we have talked about so far will be for people who are already born. That is, it will fix some of the genes at work in a part of a person's body. It will not affect the genes that a person passes on to the next generation. However, even that may be possible some day. The kind of treatment that could change the genes you pass on to your children is called germ-line therapy.
From Chapter 2, you may recall that germ cells are the special cells that divide to form eggs and sperm. Researchers are figuring out how to alter the DNA in your germ cells. If they succeed, this means that they would be able to alter the DNA that is copied and passed on through your eggs (if you are female) or your sperm (if you are male).
With germ-line therapy, genes could be "corrected" in the egg or sperm you are using to conceive. The child that results would be spared certain genetic problems that might otherwise have occurred. It may even be possible someday to use germ-line therapy to remove a disorder from your family tree forever. Your children would not inherit the problem gene. Neither would your grandchildren or your great-grandchildren.
Germ-line therapy is a long way off. However, it already is very controversial. In fact, it is so controversial, that the U.S. government currently does not allow federal funds to be used for germ-line experiments on human patients.
Most people who have thought about germ-line therapy do not oppose the idea of using it to help families rid themselves of the genes for terrible diseases. However, they are concerned because making changes to the germ line of one person can affect many people who are that person's descendants. They say that perhaps it is not right to make changes to a germ line, because some of the people who will be affected are not even born yet and therefore cannot give their consent. An even bigger concern is that making changes to germ cells could disrupt the development of the embryo or fetus in unexpected ways. For these reasons, most people feel that germ-line therapy should not be used until we fully understand its long-term effects and have addressed the ethical questions it raised.
Genetically Engineered Medicines
Although gene therapy is still experimental, in other ways genetic research already has changed how medicine is practiced. This is because of the genetically engineered drugs that are now available through biotechnology.
Take, for example, the treatment of diabetes. In the past, the only way to get insulin for diabetics was to process it from pigs and cattle. Then researchers learned how to make insulin by cloning the human gene that carries the instructions for making insulin.
Cloning and other techniques of genetic engineering have had many positive results. Genetic engineering has helped increase the supply of medical products and lower their costs. It has resulted in new drugs being created. Another benefit of genetically engineered materials is their purity. This is important, since there have been cases in the past where medical products processed from animals or human donors carried disease.
Human growth hormone is one of the medical products that can now be manufactured through genetic engineering. In the past, its only source was recently dead human donors. Getting human growth hormone in this way was difficult and controversial. It also did not recover very much of the hormone. Furthermore, there was a risk that hormones from dead bodies might be contaminated and pass on diseases. With genetic engineering, human growth hormone can now be produced in pure form in large quantities. This has made the hormone more widely available. That's why Dr. Lu faces her decision on treating Tim and Rico, the boys who are both very short.
Without treatment, neither boy will end up much over five feet tall. There is nothing unhealthy about being only five feet tall, of course. However, Dr. Lu may feel that Tim should have treatment because his one gene is not working normally. She may even feel that Rico should have treatment because his normal genes will cause him to be abnormally short.
Suppose, however, that Dr. Lu's next patients are children who will grow to be only 5 foot 4 inches or 5 foot 6 inches. If their families want them to be taller, what should she do? Where does she draw the line? It's even possible that as people hear about this growth hormone, they will demand it for their tall children to make them even taller. What will Dr. Lu do for families that want their boys to be seven-foot-tall basketball stars?
One thing that Dr. Lu has to consider is that the treatment is not quick and easy. For it to work, the boys will have to receive a great many shots over several years. The treatment appears to have side effects. For example, it may cause bad cases of acne that leave scars. Also, the treatment doesn't guarantee how much the boys will grow. Studies suggest that the treatment works better for children like Tim, who has a single mutated gene responsible for his stunted growth, compared to children like Rico, who has many genes contributing to his short build. Even so, all those years of shots may give Tim a few extra few inches and Rico even less.
Dr. Lu also must consider the fact that the treatment would be performed on children. Genetically engineered drugs are still new. It's possible that there are long-term side effects that no one knows about yet. Since Tim and Rico are children, they can't make the decision themselves. On the other hand, Dr. Lu can't wait until they are adults for them to decide, because the treatment needs to start while they are still growing.
So perhaps the decision rests with the parents. Yet before she turns the decision over to them, Dr. Lu must consider one more thing: whether the problem of being short is really a medical problem that deserves treatment. The parents may feel that if their children are taller, they will have more success. The question remains, however: What needs changing, the boys or the idea that short is bad and tall is good?
Genetic research is uncovering new ways to treat, cure, and even prevent many kinds of diseases and disorders. However, it is quite likely that the new techniques will be used in ways that don't always have to do with health.
In Dr. Lu's story, two families wanted a genetically engineered drug for their children not because the children were sick, but because they wanted them to be taller. Genetically engineered drugs, gene therapy, and germ-line therapy could open the door for lots of people to change how they or their children look. People may seek genetic treatments that will make them look younger, have more hair, or lose weight. If researchers ever figure out how genes control for behavior and ability, people may try to use that knowledge, too, for example, to improve their I.Q. or their athletic ability. There is nothing new about people wanting to improve themselves. What will be new is the opportunity to use genetic techniques to make those improvements.
There is a word that describes the use of genetic knowledge to improve the human race. The word is eugenics. "Eugenics" comes from a Greek word meaning "wellborn." For many people, the word has a bad ring to it. This is because eugenic ideas often have been used by people to claim that they are better than others.
That is what happened in Nazi Germany. Hundreds of thousands of people were sterilized, and millions more were killed, in concentration camps because the Nazis wanted to "purify" the German race. They targeted Jews and also Gypsies, homosexuals, and many others. Many of these people were victims of cruel and inhumane experiments designed to prove Nazi eugenic theories.
Even before the Nazis came to power, however, eugenic ideas were very popular in the United States and Europe. Many people in the first half of the 1900s believed that crime, poverty, and other social problems were the fault of people with "bad blood." They also believed that people of "poor stock" were reproducing more quickly than people of "good stock," leading to the decline of the human race.
The people who held these ideas considered themselves to have "good blood." They were for the most part well to do, educated, white, Protestant, and descended from northern Europeans. People with "bad blood" were people who were different from them -- poor, uneducated, of color, Catholic or Jewish, and descended from southern Europeans.
Some people who held eugenic ideas also were scientists. These scientists conducted research to support their theories. For the most part, their research was badly done and affected by their beliefs about the kinds of people who were good or bad. Even so, many states in the U.S. adopted laws to control "overbreeding" by people of poor stock. For example, thousands of prostitutes and black women were sterilized on the grounds that they were "feebleminded."
Eugenic ideas are popular even today. China has a law that forbids mentally retarded people from marrying if they have not been sterilized. Singapore offers cash rewards to well-educated women who have babies.
In the U.S., the eugenics laws from the first half of the century are no longer on the books. However, the beliefs still persist. One new way these beliefs are expressed is in the idea that poor people are poor because they have poor genes. This idea is not based on good science, but that does not prevent the idea from catching on.
A "Super" Race?
Some people fear that once we have the tools to tinker with our genes, we may be tempted to use them to design a "super" race of human beings. As a practical matter, this will probably never be possible. It's one thing to use gene therapy to get rid of an unwanted gene or two. It's a whole lot more to pick and choose the whole range of genes that make an ideal person.
First of all, you would have to decide what is the ideal. Then you would have to figure out which different genes come into play to make that ideal. And then you would have to figure out how to raise all the children so that they grow up to be ideal. Even if you could solve all those issues, you would still need the political power to make it happen. A grand plan to "improve" the human race would involve the government in personal childbearing and child-rearing choices. This would certainly be opposed by many and difficult to enforce.
So we may never make a "super" race. But in more limited ways, we may be able to shape our future. We may be able to spare ourselves and our descendants from terrible diseases and disorders. We also may be able to select some of the traits of our children. But do we want to? We also need to think about whether these choices will be available to everyone. It probably won't matter too much if some people don't get to select the eye color of their children. However, it will matter a great deal if some day only poor people suffer from terrible genetic disorders because they are the only ones who cannot afford genetic medicines and gene therapy.
We also need to worry about whether genetic technology will make us less accepting of people who are different. For example, if it is possible to predict and prevent the birth of a child with a gene-related disorder, how will we react to children we meet who have that disorder? Will we think, Why is this child alive? Will we think, Why didn't the parents "do something" to prevent the child's condition? Will we resent the medical and special education costs spent on the child? Will we put pressure on parents not to have "defective" children?
One of the important beliefs upon which this country was built is the idea that we are all "created equal." We know from the study of our genes that we are indeed very much alike. But we are not genetically equal. And no matter how much we tinker with our genes, we never will be.
However, that doesn't mean that we don't all have equal rights. It's important to remember that what we believe in is as important as what science allows us to do.
Your Genes, Your Choices
In this book, we have talked about the many ways that genetic research is changing the world we live in. It's truly exciting. It's also overwhelming. You may feel that you have little control over the way that genetic research will be used, for good or for bad.
But you do have power. The way that society uses its knowledge of genetics will be shaped by the everyday choices its citizens make.
You help shape what happens through the way you express your beliefs and opinions and by the actions you take. You also affect what happens through your community efforts, working for the passage of laws or electing leaders who believe as you do.
You made a choice to gain some control of genetic issues by reading this book. Now you have the choice to remain informed. You have the choice to use your knowledge when making personal decisions that involve the use of genetic research. And you have the choice to participate when issues involving genetics are raised in your community.
Your Genes, Your Choices is a publication of Science + Literacy for Health, a project of the AAAS Directorate for Education and Human Resources. The publication was funded by the U.S. Department of Energy. The website was built by Mike Wooldridge. Send feedback to SciLit@aaas.org.