An apparently healthy man has become the first person in the world to be prescribed a medicine based on an analysis of his genome, the entire set of genes that he inherited from his parents.
Stephen Quake, 40, a professor of bioengineering at the Stanford School of Medicine in California, has started treatment with a statin, the drug to reduce cholesterol, despite his relative youth, after researchers who assessed his chances of developing 55 conditions warned him he was at increased risk of a heart attack.
The development heralds a brave new world for medicine, in which patients will for the first time be offered personal risk analyses predicting their chances of developing dozens of diseases, and their responses to different drugs, based on a study of their genetic make-up.
But it also raises difficult ethical questions over how much patients will want to know, the harm that may be caused by information they can do nothing about and the cost of providing and explaining such highly complex data.
Last summer, Professor Quake deciphered his entire genome for less than $50,000 (£33,000), a fraction of the cost incurred by earlier pioneers who numbered no more than a dozen.
The apparently healthy Professor Quake then asked a colleague, Euan Ashley, a heart specialist at Stanford, to look at one section of his genome associated with an inherited disease called cardiomyopathy, which causes an enlarged heart and can lead to a sudden heart attack. Professor Quake was worried because one of his distant relatives had died at the age of 19 of a heart attack in his sleep.
The analysis showed rare variants in three genes associated with sudden cardiac death and Professor Ashley recommended his colleague have a full physical examination to check for signs of cardiomyopathy.
The researchers then set about analysing Professor Quake's entire genome to show which diseases he was prone to, and which he was protected from. For each disease, they assessed the contribution of the gene variants he carried to calculate his overall risk and compared it to the average risk for men of his age.
The results showed that in addition to an increased risk of a heart attack and heart disease (thickening of the arteries) he had a higher chance than average of obesity, diabetes and depression but a lower risk of Alzheimer's and macular degeneration (of the eyesight).
The researchers also discovered 10 previously unknown gene variants involved in drug response and came up with a table of drugs that were likely to work well for him, including statins to counter his predisposition to heart disease, and others that he might need lower doses of, such as warfarin, which is used to thin the blood in patients with heart disease. The findings are published in The Lancet.
Hailing the advance, Professor Quake said: "We are at the dawn of a new age in genomics. Information like this will enable doctors to deliver personalised healthcare like never before. Patients at risk for certain diseases will be able to receive closer monitoring and more frequent testing, while those who are at lower risk will be spared unnecessary tests. This will have important economic benefits as well, because it improves the efficiency of medicine."
Asked if submitting himself to the first comprehensive assessment of genetic risk for 55 diseases was alarming because of what it might have revealed, Professor Quake said: "I was curious to see what would show up.
"But it's important to recognise that not everyone will want to know the intimate details of their genome, and it's entirely possible that this group will be the majority.
"There are many ethical, educational and policy questions that need to be addressed."