Previous research suggested the ailment is inherited. The study is believed to be the first to locate a genetic marker. The disease affects an estimated 10 million U.S. children each year, though the researchers said it is vastly underdiagnosed. It causes stomach acid to back up into the esophagus, usually because of a relaxation of the valve-like muscle that keeps the lower end of the esophagus closed after eating or drinking. In children, the main symptom is spitting up or coughing.
Most youngsters outgrow it.
It is also believed to be a cause of recurring colds and upper respiratory infections. In very few cases, experts think it is a cause of some choking deaths mistakenly attributed to Sudden Infant Death Syndrome, said Dr. Christopher Post, a co-author of the study by researchers at Allegheny General Hospital in Pittsburgh. Heartburn is the major symptom in adults affected by the ailment. It can cause constant throat irritation that can lead to esophageal cancer . Treatment includes diet, drugs and sometimes surgery.