Scientists link missing gene to child obesity

By Associated Press
Monday, December 7, 2009

NEW YORK -- Some children get severely obese because they lack particular chunks of DNA, which kicks their hunger into overdrive, researchers report.

The British scientists checked the DNA of 300 children who became very fat, on the order of 220 pounds by age 10. The researchers looked for deletions or extra copies of DNA segments.

They found evidence that several rare deletions may promote obesity, including one kind found in less than 1 percent of about 1,200 severely obese children.

That deletion, on chromosome 16, causes trouble because it removes a gene that the brain needs to respond to the appetite-controlling hormone leptin, said Sadaf Farooqi of Cambridge University.

In her study, children with a chromosome-16 DNA deletion "have a very strong drive to eat," said Farooqi, who co-led the study. "They're very, very hungry; they always want to eat." The work, reported on Sunday by the journal Nature, has already produced a real-world payoff. Farooqi said four children with chromosome-16 deletion drew the attention of British child-welfare authorities, who blamed the parents' overfeeding.

"We were able to intervene" and get the parents of two children off the hook, and the other two cases are under discussion, she said.

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