Sam Berns, 15, who has the very rare premature-aging disease progeria, plays the drums in his high school's marching band. Courtesy of the Progeria Research Foundation hide caption

itoggle caption Courtesy of the Progeria Research Foundation

Andy Tranfaglia, 23, who has Fragile X syndrome, rides a horse with his mother, Katie Clapp. Katie Clapp hide caption

itoggle caption Katie Clapp

Canned food is a source of BPA exposure, but researchers aren't sure whether it causes childhood obesity. Above, the soup isle at a grocery store in Washington, D.C. Maggie Starbard/NPR hide caption

itoggle caption Maggie Starbard/NPR

Gregg Allman and Natalie Cole perform at the Tune In to Hep C benefit concert at the Beacon Theatre in New York on July 27, 2011. Both singers have battled chronic hepatitis C. Rob Bennett/AP Images for TuneInToHepC.com hide caption

itoggle caption Rob Bennett/AP Images for TuneInToHepC.com

Care managers tend elderly people in March 2012 in Minamisoma, Japan. The home's residents were evacuated eight days after the Fukushima Dai-ichi nuclear power station was crippled by the March 11, 2011 tsunami. Koji Sasahara/AP hide caption

itoggle caption Koji Sasahara/AP

A newly discovered disease in boa constrictors could provide the missing link in the latent Ebola virus. iStockphoto.com hide caption

itoggle caption iStockphoto.com

A PET scan of the brain of a person with Alzheimer's disease. U.S. National Institute on Aging/via Wikimedia Commons hide caption

itoggle caption U.S. National Institute on Aging/via Wikimedia Commons

CamelBak-brand water bottles on display at an outdoor supply store in Arcadia, Calif., in 2008. The company removed BPA from the plastic in its bottles. David McNew/Getty Images hide caption

itoggle caption David McNew/Getty Images

Researchers studying brains want to know what's happening in an area called the premotor cortex — the place in the brain that gears up for something the body is about to do, like swimming. Above, Michael Phelps dives off the starting blocks in the final heat of the men's 400-meter individual medley during the 2012 U.S. Olympic Swimming Team Trials in Omaha, Neb., on June 25. Jamie Squire/Getty Images hide caption

itoggle caption Jamie Squire/Getty Images

A PET scan of the brain of a person with Alzheimer's disease. U.S. National Institute on Aging/via Wikimedia Commons hide caption

itoggle caption U.S. National Institute on Aging/via Wikimedia Commons

An artist's illustration of events on the sun changing the conditions in near-Earth space. NASA hide caption

itoggle caption NASA