Doctors use gene sequence to predict health risks

LONDON – The next time Stephen Quake is prescribed a drug, he says he won't worry about having a bad reaction. The Stanford University professor will simply consult his genome to see if there are any warning signs in his DNA.

More than two dozen of Quake's scientist colleagues combed through his genetic code to assess his chances of heart disease, diabetes, cancer and how he might react to common medicines. The results were published Friday in the medical journal, Lancet.

It is an example of the kind of personalized medicine that might one day be possible if doctors have a map of their patients' DNA. Seven other people have had their genomes sequenced. Last year, Quake's genome was published in the journal Nature Biotechnology, before it was analyzed for health risks.

But as the gene scan becomes more widely available, experts warn interpreting the data may be trickier than obtaining it. "We need to get better at explaining what this information means for patients," said Euan Ashley, an assistant professor of medicine at Stanford and the Lancet paper's lead author.

For months, 30 scientists studied more than 2 million gene variants in Quake's DNA. They found genes linked with sudden cardiac death and others suggesting he might be resistant to the anti-clotting drug clopidogrel. Based on their findings, Ashley recommended Quake start taking cholesterol-lowering statins. Quake declined.

The research was paid for by the U.S. National Institute of General Medical Sciences, the National Heart, Lung and Blood Institute and others.

When the first human genome was sequenced, it cost about $3 billion. Decoding Quake's genome cost around $50,000. Experts said the price of getting a complete genome sequence may drop to less than $1,000 in the next few years, tempting more people to get their DNA mapped.

Some experts said legislation might be needed to protect such sensitive information. "The genie is now out of the bottle," said Nilesh Samani, of the department of cardiovascular sciences at the University of Leicester. He was not connected to the genome research. "We need to think carefully about whether we need laws to prevent genetic information from getting into the wrong hands."

Muin Khoury, director of the National Office of Public Health Genomics at the U.S. Centers for Disease Control and Prevention, said it wasn't clear how genome sequences might help. "We simply cannot interpret ... the vast amount of emerging data," he said. "The current information is incomplete, uncertain, potentially misleading and could lead to unnecessary procedures," he said.

Khoury said that without a medical reason for getting a genome sequence, obtaining one was premature. "The relationships between our genome and most health and disease indicators are so far unknown or unvalidated," he said.

Quake also cautioned that getting a genome sequence isn't for everyone. "All you hear about when they talk about your genome is ways you're going to die and get sick. It doesn't tell you you're going to be happy or a great athlete," he said. "If you're a worrier, this is not for you."