Friday, October 17, 2008

Blood test finds coronary disease

Genetic markers predict coronary artery disease, Duke doctors say. Those pesky genes again! How odd that eating fruit and vegetables has no such predictive power!

A simple blood test could soon replace expensive and invasive exams to detect coronary artery disease. The test, announced Wednesday by doctors at Duke, is being developed after the discovery of genetic markers that show the presence and intensity of blockage in coronary artery disease, said a Duke cardiologist who co-authored research on the link. Such a blood test could save millions of dollars annually by allowing some patients to avoid risky procedures in which catheters are inserted into patients' arteries.

"I think it is a big deal," Dr. William E. Kraus, a Duke cardiologist, said in an interview Wednesday. "What we want is a test that tells us the status of your disease today and if what you have is heart disease." Kraus' research was published in the medical journal Circulation: Cardiovascular Genetics.

Current detection of the disease -- the leading cause of death in the United States and a top killer in North Carolina, with 23,610 deaths in 2006 -- can require expensive tests such as echocardiograms, stress tests and imaging techniques that use radiation. "A blood-based test to diagnose coronary artery disease would be less invasive and risky and would prevent patients from [receiving] radiation exposure," Kraus said in a statement.

Raleigh retiree Robert Sharpe said going directly from a blood test to having a catheter inserted would have been an improvement over what he went through before two recent heart surgeries. "It would have been a whole lot easier," said Sharpe, 74, who now stays in shape at the Institute of Lifestyle & Weight Management in Raleigh. "I had a stress test and all of that."

The finding that 14 specific genes tend to accompany the narrowing of arteries arose from research by Duke and CardioDx, a molecular-diagnostics company in California that helped fund the study. It's based on the examination of genes in 41 heart patients, some from Germany and some from Duke. Together, the 14 genes form a "signature" that indicates the presence of coronary artery disease, but may not be a cause or effect of the disease, researchers said.

Two Triangle cardiologists not involved in the research said it looks promising, but noted the small number of cases involved. Patients from a variety of backgrounds will be tested in larger trials under way at 28 sites across the United States. "If these findings hold for this broad group of population, the test could prove to be a valuable supplement in our management and treatment of patients with coronary heart disease," said Dr. Sidney Smith, a UNC-Chapel Hill cardiologist.

Dr. Joe Falsone, an invasive cardiologist at Wake Heart & Vascular Associates, called the discovery "potentially exciting news." "We could probably use this as a screening tool for patients we thought were at high risk," Falsone said.


Leading geneticist Steve Jones says human evolution is over

Human evolution is grinding to a halt because of a shortage of older fathers in the West, according to a leading genetics expert. Fathers over the age of 35 are more likely to pass on mutations, according to Professor Steve Jones, of University College London. Speaking today at a UCL lecture entitled "Human evolution is over" Professor Jones will argue that there were three components to evolution - natural selection, mutation and random change. "Quite unexpectedly, we have dropped the human mutation rate because of a change in reproductive patterns," Professor Jones told The Times.

"Human social change often changes our genetic future," he said, citing marriage patterns and contraception as examples. Although chemicals and radioactive pollution could alter genetics, one of the most important mutation triggers is advanced age in men. This is because cell divisions in males increase with age. "Every time there is a cell division, there is a chance of a mistake, a mutation, an error," he said. "For a 29-year old father [the mean age of reproduction in the West] there are around 300 divisions between the sperm that made him and the one he passes on - each one with an opportunity to make mistakes. "For a 50-year-old father, the figure is well over a thousand. A drop in the number of older fathers will thus have a major effect on the rate of mutation."

Professor Jones added: "In the old days, you would find one powerful man having hundreds of children." He cites the fecund Moulay Ismail of Morocco, who died in the 18th century, and is reputed to have fathered 888 children. To achieve this feat, Ismail is thought to have copulated with an average of about 1.2 women a day over 60 years.

Another factor is the weakening of natural selection. "In ancient times half our children would have died by the age of 20. Now, in the Western world, 98 per cent of them are surviving to 21."

Decreasing randomness is another contributing factor. "Humans are 10,000 times more common than we should be, according to the rules of the animal kingdom, and we have agriculture to thank for that. Without farming, the world population would probably have reached half a million by now - about the size of the population of Glasgow. "Small populations which are isolated can evolve at random as genes are accidentally lost. World-wide, all populations are becoming connected and the opportunity for random change is dwindling. History is made in bed, but nowadays the beds are getting closer together. We are mixing into a glo-bal mass, and the future is brown."



Anonymous said...

Wait, what? There are fewer older fathers *now* than there have been over the course of thousands of years? When the average life expectancy was, what, 35? When women and men are becoming parents at ever-later ages than at any time in human history (often with extreme amounts of medical intervention)? Is this guy for real?!

Anonymous said...

Also: evolution functions better across larger populations (the idea that evolution is time-based is flawed) and, with a popuulation that has done nothing but explode over the past 100 years, the chance for a mutation to occur, coupled with the older ages of this flawed hypothesis (I don't even agree that mutation is more readily spurred by aging fathers) sounds like a recipe for a mutation-a-thon if this fellow is to be believed at all.