Sequencing of human genome is a first step to many answers

Scientists have already isolated the gene that causes cystic fibrosis, but mapping the entire genome may help them improve treatment by telling them if other genes are involved

Project is likely to fuel medical research for many years

By Sean Swint
WebMD Medical News

(WebMD) -- Sequencing the entire genetic material in humans will no doubt have a seismic effect on medicine in the future. But what kind of medical breakthroughs can we expect to come out of the research, and who will most benefit?

Researchers have been racing to be the first to sequence the human genome -- the complete set of human genes -- in an effort known as the human genome project. Knowing the function of each part of the DNA could potentially lead to the development of drugs tailored to each individual's genetic makeup. Doctors would be able to pick the medication that would work best for you, and to reduce the chance of side effects.

Already, DNA research has given doctors the ability to target the proper doses of some drugs to people, and to rule out certain drugs for people in whom they are likely to cause side effects.

A genetic "smart card" -- a plastic card encoded with a person's genetic information that patients could present to doctors to help them make treatment choices -- is likely not far off.

No immediate answers

"Maybe the best thing about having the human genome in hand is that it opens up a tremendous number of possibilities to us," Elaine Mardis, Ph.D., told WebMD. But, she said, "the scenarios and how they play out are largely speculative at this point."

Mardis is assistant director of the genome sequencing center at Washington University in St. Louis.

"I think most reasonably well-informed people understand the sequence won't provide immediate answers," Mardis said.

The fundamental premise of the human genome project, and all it can really provide, Mardis said, "is that overwhelmingly, as far as genes go, one person is reasonably close to another person."

The problem, she said, is the abnormal, or mutated, genes that cause disease, and the genome project will not answer the questions about all those potentially lethal genes.

The new discoveries promise to be a golden opportunity for drug companies, because there is a lot of money to be made in discovering new medications. And that, of course, is a golden opportunity for people with a variety of ailments.

Initial benefits

Parkinson's disease is a genetic disease that makes it difficult for patients to control their movements. Genomic mapping could help researchers find how many genes are responsible

The initial benefits we are likely to see from the project, though, will be in the ability to test people for certain diseases that are due to abnormal genes they possess, such as Alzheimer's disease, Mardis said.

She is also hopeful that researchers may be able to stop genes that are responsible for certain deadly diseases, such as cancer.

Although some diseases, such as cystic fibrosis, are caused by a single abnormal gene, many others are caused by more than one bad gene. So finding one genetic mutation may not be the only piece to the puzzle.

Genetic material by no means contains all the answers to medical mysteries. With ailments such as high blood pressure, heart disease and stroke, Mardis said, finding a responsible gene will help identify people at risk for the disease, but a healthy lifestyle will still play a role in fighting it.

Although sequencing the human genome will not lead to immediate results, it is an accomplishment that brings a lot of hope.

"It lays a huge puzzle out in front of us, and that sounds like a bad thing, but without the pieces of the puzzle we wouldn't have anywhere to start," Mardis said. "It's going to fuel medical research for the next 20 or 30 years in a huge, huge way."

Vital information

• The human genome project may provide a blueprint of human genetics, but experts say developing it will only mark the beginning of the research. Scientists still have to figure out how to use the information.
• Scientists know some diseases such as cystic fibrosis are caused by a single defective gene. But experts say there are probably several genes involved with developing most diseases. Also, researchers need to consider other factors in disease, such as environmental influences.
• Understanding people's genetic makeup also could help doctors predict their patients' future health. But knowing someone is at risk of developing a disease does not mean doctors can do anything to prevent or treat it.

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