Gene Mapping: Predicting Your Future Health

June 3, 2010— -- Imagine for a moment that you were offered the chance to know every gene mutation that you and your family have in your DNA. Three billion bits of data, made up of four powerful letters -- A, T, C and G -- arranged in a sequence can offer you the map to your entire genome.

Knowing this sequence could potentially mean that you might know many of the diseases you could face during your lifetime.

Would you really want to know?

John and Judy West of Cupertino, Calif., did.

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John and Judy West, both 53, and their children, Anne, 17, and Paul, 14, paid almost $200,000 to have their entire genetic code read by the sequencing company Illumina.

The family of four became the first in which every member's genome has been sequenced for non-medical reasons. They say they hope to advance science and unlock personal medical information that will lead them to healthier lives.

"We do view ourselves pioneers," said daughter Anne West.

"It's rather like having, being one of the first people to have a telephone. Who do you talk to?" said Judy West.

In fact, for many who choose to undergo genetic testing, specific tests may uncover gene mutations that can show an increased risk for a particular disease.

Newborn screening tests and BRCA gene testing are among those genetics tests currently administered by experts. However, the emergence of direct-to-consumer sequencing companies, such as 23andMe, has arguably given people the power to learn their own personal gene map.

"The earlier you can catch a disease the better," John West said. "And if you can see it before there are any symptoms just by looking in the genes, that's terrific."

But while some use genetic testing to identify specific genetic mutations that have been found to increase the risk of certain types of diseases, whole genome sequencing can show potential codes as yet undeciphered by geneticists.

In fact, sequencing genomes is so new, there is no program yet to decode the data.

"It doesn't come with any medical interpretation at all," John West said. "There's no guidebook. There's no glossary."

Instead, 17-year-old Anne has been deciphering her family's medical code on a spreadsheet on the family computer. The West family said they discovered they have a gene that puts them at increased risk of blood clots, especially if John West and his daughter Anne West consume large amounts of vitamin K.

"Part of the indication for me is that I shouldn't eat spinach," John West said. "So, the simpler thing is just to say, 'I love lots of other kinds of salads. Instead of a spinach salad, I'll have a lettuce salad.'"

Do you Really Want to Know?

While the West family said they do not regret their choice to sequence their genomes, the family's decision has raised the question of whether it is worth sequencing children without medical necessity.

"Adults always make those decisions for their children," John West said. "And you have to make choices as you go through life, and you try to make the best choices. If you don't act, that's also a choice."

Many doctors and ethicists argue that while DNA data may prove medically useful, there is not enough evidence of benefit to warrant testing healthy children.

Genome sequencing could reveal information such as high risk of Alzheimer's and other diseases that are irreversible by today's medicine. And since many doctors may not be able to provide preventive strategies for these diseases, the person tested may decide after the fact that he or she would rather not have known.

"The issue of protecting the right not to know is an important one," said Dr. Francis Collins, director of the National Institutes of Health. "Nobody should be forced to find out genetic information about themselves if they don't want it."

While not all children are the same, perhaps waiting to tell some children might save them from anxiety, Collins said.

"You can make a case for not revealing all of the information right away, giving that person a chance to decide when they're 18 or 21 years old, do they really want to know about their Alzheimer's disease risk or the late onset cancer risk," Collins said.

Knowledge of personal disease risk also raises the question of whether life insurance companies, health insurance companies or potential employers might be able to access the information.

The 2008 Genetic Information Nondiscrimination Act (GINA) enacted by Congress prevents group health plans from denying coverage to a healthy individual or raising a person's premiums based solely on a genetic predisposition to developing a disease. However, Collins said, GINA does not prevent discrimination for long-term care insurance, disability or life insurance, which may need to be considered should genome sequencing expand.

Your Future Health

Still, the prospect of whole genome sequencing has further opened the doors to discovering new genetic codes and their link to disease.

Collins said he expects the price of whole genome sequencing to drop to under $1,000, and the test may become a more widely accepted option.

"It will become eventually and probably in the next five or six years, cheaper just to synchronize the entire genome and get all the information at once, and I think that's where newborn screening will go," he said.

In the meantime, one of the best ways to understand personal risk and prevent disease is to know your family history, Collins said.

While the West family said there is much they do not know about their genome sequence, what they have found has helped them better understand their risk for a particular disease and work to prevent its onset.

"I'm of the opinion that if there's anything in my genome that would make me more prone to a disease, if I find out now, I can possibly go into that field and try to research a cure for that," said Paul West.