Health & Science

Using DNA tests to diagnose illness

DNA testing to identify disease-causing mutations used to be too expensive and time-consuming for use in diagnosing individual patients. But with the cost of such DNA sequencing dropping, a growing number of parents of children with mysterious disabilities are turning to the tests for both diagnosis and possible treatments, The New York Times reports. The tests, in which scientists sequence all of a patient’s genes, now cost less than $9,000 and are often covered by insurance. “Most people originally thought of using it as a court of last resort,” says Columbia University pediatrician Wendy K. Chung. “Now we can think of it as a first-line test.” The test is no panacea: It detects a genetic abnormality in about 30 percent of cases, and leads to better management of disorders in only 3 percent. But for many parents who have spent years seeking explanations for their children’s disabilities, gene sequencing can offer relief, and sometimes even more. Twins Alexis and Noah Beery, for example, were 14 when sequencing revealed a mutation that was preventing them from synthesizing the neurotransmitters dopamine and serotonin, causing tremors and difficulty breathing. The problem was quickly treated with drugs, and three weeks later, one of the twins began running track. Most families aren’t that lucky, cautions William Gahl of the National Institutes of Health. “We try to make expectations realistic.”

Fish on drugs

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Psychiatric medications passing through sewage treatment plants could be dramatically changing the behavior of fish. After researchers discovered low levels of common anti-anxiety drugs called benzodiazepines in perch living downstream from a treatment plant in southern Sweden, they tested the same concentrations of the drug on fish in the lab. They found that the medicine made the fish lose their inhibitions, causing them to eat more than unexposed fish do and to be less cautious about straying from their schools—behaviors that, in the wild, could have major ecological consequences. Drug-addled fish with the munchies might reduce populations of zooplankton, which could lead to blooms of the algae that zooplankton consume; bolder fish might also become more vulnerable to predators. Researchers say hundreds of different pharmaceutical drugs are likely slipping unchecked into waterways—and having unknown effects on fish and other vertebrates. “It’s scary when you think about it,” ecologist Tomas Brodin of Sweden’s Umea University tells BBCNews.com. “It’s a huge cocktail of drugs, and fish are experiencing it 24/7—breathing it, drinking it, and eating in it.”

Better parenting through TV

The average American preschooler watches more than four hours of TV a day, well over twice the screen time experts recommend. But now a new study suggests that what they watch could matter more than how much they watch. Researchers divided the parents of more than 500 children ages 3 to 5 into two groups; they gave half of them advice on choosing “pro-social” children’s shows that stress kindness and cooperation, such as Sesame Street, while allowing the other half to continue their kids’ normal TV routines, which often included violent shows like Power Rangers. After six months, the children who had watched the prosocial programming had become demonstrably less aggressive toward others, despite watching roughly the same amount of TV as their peers. The difference was especially pronounced among low-income boys, who “are most at risk of being victims and perpetrators of aggression,” study author Dimitri Christakis, of Seattle Children’s Research Institute, tells Time.com. The study comes on the heels of another one, which found that every hour of TV kids watched on an average weeknight increased their risk of landing in prison as adults by 30 percent. “It’s hard to imagine seeing the same results if they had just watched PBS documentaries,” says Christakis.

Restoring lost sight

People who’ve lost their eyesight to a common degenerative disease can now “see’’ again with a newly developed bionic eye. Using a video camera mounted on eyeglasses, the Argus II System captures visual information, then beams it to electrodes implanted in the retina, which conveys image-forming signals to the brain. The system lets people stricken with retinitis pigmentosa—a disease that damages retinal cells and affects about 100,000 Americans—distinguish light from dark and recognize large objects and letters. The 50 participants in the clinical trial for the device reported that they could spot curbs, crosswalks, people, and cars, and sort white socks from black. “Without the system, I wouldn’t be able to see anything at all,” Elias Konstantopoulos, a retired electrician and one of the trial’s participants, tells The New York Times. “When you have nothing, this is something. It’s a lot.” Researchers now hope to improve the system to let people see more detail and in color.