Genetic testing for sports genes courts controversy

The DNA scans, the first of an expected wave of attempts to use genes to enhance athletic performance, can steer children toward games they are most likely to win — and perhaps get scholarships to play, the companies say. The tests also let children — and adults — tailor workouts to their innate skills, the firms say, as well as spot those prone to life-threatening heart problems, concussions and other injuries.

“The main purpose of the test is to maximize performance in the minimum amount of time and minimize risk,” said Bill Miller, chief executive of American International Biotechnology Services in Richmond, which began selling the test three weeks ago.

Critics, however, see the kits as the latest in a flood of questionable genetic tests that entrepreneurs are hawking. No one can accurately gauge the influence of genes on athletic abilities or vulnerabilities, they say. The results may be needlessly alarming or falsely reassuring, they say. Skeptics also fear that the trend will encourage overzealous parents and coaches to push kids into sports they dislike or discourage them from physical activities they enjoy — and might succeed at — despite their genes.

“This is really disturbing,” said Lainie Friedman Ross, a pediatrician and bioethicist at the University of Chicago. “Sports and physical activity should be fun for kids. It shouldn’t be, ‘You’re going to be the world’s greatest athlete’ or ‘Give up now, kid, because you won’t have a chance’ because of your genes.”

FDA as referee?

The growing availability of mail-order DNA scans has spurred excitement about finding genetic clues to ancestry, health and proclivities. But the testing has also raised alarm because genetic data can be misleading, misinterpreted and misunderstood, and it can leave consumers vulnerable to discrimination by employers and insurers.

The plethora of tests has prompted the Food and Drug Administration to begin stepping in, causing one company last year to abandon plans to sell a genetic screen at Walgreens stores, others to discontinue offering tests directly to consumers and some to begin working with the agency to validate their methodology.

‘This is just a tool’

Another company, Atlas Sports Genetics of Boulder, Colo., was the first to offer athletic DNA testing in the United States. For $169, Atlas sells an Australian lab’s test that analyzes a gene that controls a key muscle protein. The ACTN3 protein can make muscles better at producing quick bursts of power.

“A lot of people get confused and think we’re saying this can tell you whether you or your child will be the next Michael Jordan,” said Nat Carruthers, Atlas’s president of operations. “It doesn’t tell you that. But it will tell you whether you are producing this protein and whether you are predisposed to be good at a sprint sport or an endurance sport.”

The results, obtained by mailing to a lab a saliva sample swabbed from inside a cheek, can help active people maximize their workout regimens and sports choices based on their muscle type, Carruthers said.

“If someone trying to run marathons says, ‘I’m trying to do all the endurance training, but it’s just not working out. I can’t keep up with the workouts,’ or they are trying to lose weight and they say, ‘I’m going to the gym and I just can’t do these workouts,’ we can say, ‘You need to train in a different way,’ ” Carruthers said.

Bradley Marston of Bountiful, Utah, had his 10-year-old daughter, Elizabeth, tested last year because he was curious to learn more about why she excelled at soccer.

“I already knew she had that something special. This is just a tool to help me determine what to do with her strengths as well as some of her shortcomings,” Marston said.

Elizabeth’s test indicated that her muscles are predisposed more to quick spurts of power than to long trials of endurance.

“I am not the type of father or parent that is pushing my daughter to succeed. It’s not all about winning. The focus is about having fun. This tool can just help us,” Marston said.

Genetics of performance

Although the ACTN3 gene has been linked to enhanced performance among some elite sprinters, it does not seem essential to Olympic-level athletics.

“It looks like the gene does contribute something, but only a very small amount at the very, very elite levels,” said Stephen M. Roth, who studies the genetics of physical performance at the University of Maryland. “For 99 percent of the world, it does not matter.”

More recently, American International began screening for the ACTN3 gene, as well as six others that the company says influence strength, energy and endurance. In addition, the $200 test checks cheek swabs for variations of three genes that the company says can signal risks for fatal heart muscle and rhythm emergencies. Sports X Factor can also supposedly identify those who are vulnerable to concussions and need more rest after suffering a head injury to minimize the risk of brain damage.

Targeting children

“One of the main target audiences is kids,” Miller said. “We want to make sure they are not out there blindly playing with one of these mutations and have a heart attack or a concussion. It gives parents peace of mind that their kid is not going to drop dead in the middle of a workout.”

Critics, however, argue that too little is known about the genes in the test panel to reliably interpret the results.

“If the test comes back negative, the parent might say, ‘Put them back in,’ ” said Carl Foster, a professor of exercise and sports science at the University of Wisconsin at La Crosse. “If you get your kid back into competition too quickly and he gets another concussion, the kid is dead now.”

Several experts expressed concern about including the gene called ApoE for information about concussions. ApoE plays a role in Alzheimer’s disease, which means youngsters excited about tomorrow’s soccer game and their parents may find out that they are at risk for a devastating brain disease decades later.

“I think this company is a good advertisement for the need for more regulation of . . . genomic testing,” said Hank Greely, a Stanford University lawyer and bioethicist.

Despite such concerns, one of American International’s first clients was Ryan Muetzel, who was trying it out for clients at his Athletes Edge private training company in Boca Raton, Fla. Muetzel’s test concluded that he’d be good at track and field but prone to knee injuries — all of which he said is true.

“If kids are trying to get college scholarships, or just be happy and successful, what is going to make them happy?” he asked. “No one wants to be the worst kid on the team.”

Source:Rob Stein,Washington Post; Published: May 18,2011

Is Fitness in the Genes?

Why do some people respond to an aerobic workout routine by becoming incredibly fit, whereas others who exercise just as hard for months end up no fitter than when they began?

That question has bedeviled countless people who’ve started exercise programs. It has also motivated a major new study of the genetics of fitness. Scientists long have known that when any given group of people faithfully follows the same aerobic workout routine, some increase their cardiorespiratory fitness substantially, while an unfortunate few seem to get no benefits at all. But what, beyond the fundamental unfairness of life, makes one person’s body receptive to exercise and another’s resistant? According to the new study, which will soon be published in The Journal of Applied Physiology, part of the answer may depend on the state of specific genes.

For the study, researchers from the Pennington Biomedical Research Center in Baton Rouge, La., and other institutions examined the genomes of 473 healthy white volunteers. All were part of the Heritage Family Study, an ongoing (and multiethnic) examination of exercise genetics that already has provided reams of epidemiological information about whether various exercise traits tend to run in families. (It turns out that many do, including the basic drive to exercise at all.) But neither the Heritage Study nor any other experiment to date had identified the specific genes that might be associated with a person’s physical response to exercise.

The researchers looked at 324,611 individual snippets over all. Each of the volunteers had already completed a carefully supervised five-month exercise program, during which participants pedaled stationary bicycles three times a week, at controlled and identical intensities. Some wound up much fitter, as determined by the increase in the amount of oxygen their bodies consumed during intense exercise, a measure called maximal oxygen capacity, or VO2 max. In others, VO2 max had barely budged. No obvious, consistent differences in age, gender, body mass or commitment marked those who responded well and those who continued to huff and struggle during their workouts, even after five months.

But there was a divergence in their genomes. The researchers identified 21 specific SNPs, out of the more than 300,000 examined, that differed consistently between the two groups. SNPs come in pairs, since each of us receives one paternal copy and one maternal copy. So there were 42 different individual versions of the 21 SNPs. Those exercisers who had 19 or more of these SNPs improved their cardiorespiratory fitness three times as much as those who had nine or fewer.

One SNP in particular, located on a gene known as ACSL1, seemed especially potent, possibly accounting for as much as 6 percent of the difference in response among people, a high percentage by the standards of genomewide association studies. This gene already has been shown to play a role in how the body metabolizes fats, which might partly explain why it also affects exercise response. But, said Claude Bouchard, who holds the John W. Barton Sr. Endowed Chair in Genetics and Nutrition at Pennington and was lead author of the study, “far more research is needed before we can say” just how any particular gene influences the body’s response to aerobic exercise, let alone what additional genes might be involved in that response.

Still, the findings, preliminary or not, raise several intriguing concerns. How, for one, can any of us tell if we harbor the ideal SNPs for a robust aerobic response to endurance exercise? And if it turns out that we don’t carry those advantageous snippets of genes, can we take to the couch, since our fitness levels won’t budge much even if we dutifully pedal or run?

“It will be years, if ever,” said Dr. Bouchard, before gene tests exist that can reliably separate high and low responders. Even if and when such tests become available, he continued, the results will not constitute an excuse for skipping workouts. “There are countless other benefits provided by exercise,” he said, apart from whether it raises your VO2 max. “Exercise can reduce blood pressure and improve lipid profiles,” he said. It can better your health, even if, by certain measures, it does not render you more aerobically fit.

Source: Gretchen Reynolds, New York Times, March 16, 2011


--------------------------------------------------------------------------------