Gene scan shows man's risk for heart attack, cancer
May 3, 2010, 12:42 am TWN
A California college professor who sequenced his own genome has had it analyzed — and discovered he has a high risk of dropping dead of a sudden heart attack, as well as a high prostate cancer risk.
The analysis, published in the Lancet medical journal, illustrates the challenges facing doctors, patients and healthcare systems as such DNA maps become easier to get and as people seek to find out their disease risks.
As for his own findings, Stanford University bioengineering professor Stephen Quake found them “interesting.”
“I was curious to see what would show up,” Quake said in a statement.
“But it's important to recognize 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 going forward.”
The Stanford team designed a computer algorithm to bring together Quake's known and genetic health risks.
For example, as a 40-year-old white male, Quake began with a 16 percent lifetime chance of developing prostate cancer. But after taking his genes into account, the researchers put his risk at 23 percent.
His Alzheimer's risk, however, plummeted from 9 percent for most white men his age to 1.4 percent when genetics were considered.
Quake's genome cost about US$50,000 to sequence using a Heliscope sequencer from Helicos BioSciences. It was double-checked using an Illumina Inc. sequencer.
But the price is falling. The latest machines from companies like Illumina and Life Technologies Corp can map out a patient's whole DNA code for as little as US$5,000.
“The $1,000 genome is coming fast,” said cardiologist Dr. Euan Ashley, who led the team analyzing Quake's sequence.
Hours of expert interpretation went into Quake's genome but Ashley said this could eventually be reduced to a computer algorithm.
Happening for the Average Guy
“I think it will come to the point where this is happening for the average guy,” Ashley said in a telephone interview. “We think the genomic information is going to be cheap and it is going to be fast ... and the analysis could be run with the click of a mouse at any time .”
While Quake's cholesterol levels were healthy, the genes made Ashley think twice.
“We discovered rare variants in three genes that are clinically associated with sudden cardiac death — TMEM43, DSP, and MYBPC3,” Ashley's team wrote. Plus Quake had a distant relative who had died suddenly in his sleep at the age of 19.
Checks of other genes showed Quake would respond well to cholesterol-lowering statin drugs, and that he was unlikely to have an unusual side-effect from the drugs.
Ashley prescribed a statin for Quake, but to his surprise, Quake has not filled it.
“It's human nature — even with the evidence from their own genome, they are reluctant to take the doctor's advice,” Ashley said. “I will wear him down.”
Hank Greely, director of Stanford's Center for Law and the Biosciences, points out the huge issue facing doctors and their patients — how much does anyone want to know?
“Patients, doctors and geneticists are about to be hit by a tsunami of genome sequence data. The experience with Steve Quake's genome shows we need to start thinking — hard and soon — about how we can deal with that information,” Greely said in a statement.
“Who will provide skilled interpretation of whole-genome sequence to millions of patients?” Greely asked in a commentary in The Lancet.