Children's Health

Genes Pinpointed for Common Childhood Obesity

Researchers Suspect a Role in Gut Function

At least three newly identified genes seem to work in the digestive system.

The protein compound made by one of the genes, for example, is known to turn off the body?s defenses against H. pylori bacteria, which are a cause of stomach ulcers. H. pylori infection, researchers note, is more common in obese people.

In a news conference, Karen Winer, MD, a medical officer at the Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD), called the study "groundbreaking work" because it involved the largest collection of genetic material ever compiled to investigate common childhood obesity. The NICHD funded the study.

Previous gene studies had focused on extreme childhood obesity, which is usually associated with defects in a single determining gene, like the inherited Prader-Willi syndrome.

"Common obesity is a very complex disease -- not only genetic or environmental (high-fat diet, inactive lifestyle) -- but an interaction between these two factors," says William S. Garver, PhD, an assistant professor in the department of biochemistry and molecular biology at the University of New Mexico Health Sciences Center in Albuquerque.

Garver studies genes related to obesity, but he was not involved in the research.

"It is likely that most common obesity genes interact with an environmental factor or other 'modifying genes' to promote weight gain," he says in an email to WebMD.

There's still a lot to be learned about the genetic components of childhood obesity. Taken together, Grant says all the markers known to be associated with the condition probably still only account for 5% to 10% of a person?s genetic risk.