The four children in Britain were obese, and had caught the eye of child welfare authorities. In each case, the child’s parents were blamed for overfeeding them.
Except it wasn’t the parents’ fault.
The children each have a chromosome 16 DNA deletion, which means they are missing a chunk of DNA that the brain needs to respond to its appetite-control center, according to a British study in the journal Nature released Sunday. The deletion of chromosome 16 kicks the child’s hunger into overdrive.
These children "have a very strong drive to eat," said Dr. Sadaf Farooqi of Cambridge University, who co-led the research. "They're very, very hungry, they always want to eat."
It’s so easy to make the wrong judgment in matters like this.
Perhaps you see an obese child at the mall, and what do you think? That they aren’t being fed correctly, or that there is no discipline in the house? Or perhaps your own child is very overweight, despite your attempts to help, and you just cannot figure out why. It is possible that DNA is part of the answer.
In the research, scientists checked the DNA of 300 severely obese children (around 220 pounds by age 10). They compared the DNA with that of 7,000 healthy volunteers, and found evidence that any of several DNA deletions can promote obesity. The chromosome 16 deletion was one they studied further. It is rare, affecting less than 1 percent of about 1,200 such children.
That may seem small. But consider this: That could be 10 kids in a school of 1,000.
From an Associated Press story:
“While scientists had previously discovered particular genes that promote obesity when damaged, the new work looked at larger chunks of DNA that can span several genes. The chromosome 16 deletion includes nine genes.
“Eric Ravussin, an obesity expert at the Pennington Biomedical Research Center in Baton Rouge, La., who wasn't involved in the study, said the work provides "a gold mine of information." That's because it identifies specific chromosome areas that scientists can explore to discover obesity-related genes, he said.”
From Telegraph.co.uk:
"This is the first evidence that copy number variants have been linked to a metabolic condition such as obesity," said Dr Matt Hurles from the Wellcome Trust Sanger Institute, one of the leaders of the study.
Farooqi added: "This study shows that severe obesity is a serious medical issue that deserves scientific investigation. It adds to the growing weight of evidence that a wide range of genetic variants can produce a strong drive to eat.”
And about those four children?
"We were able to intervene" and get the parents of two children off the hook, Farooqi said, and the other two cases are under discussion.
That's happened before when the scientists uncovered genetic causes for severe childhood obesity, she said.
"It's a slightly unusual outcome of our research, but one we think is very important," she said.
The Associated Press story:
http://abcnews.go.com/Technology/wireStory?id=9263514
The Telegraph.uk.com:
http://www.telegraph.co.uk/health/healthnews/6744152/Childhood-obesity-linked-to-mutant-gene.html
The BBC:
http://news.bbc.co.uk/2/hi/health/8394991.stm
The Cambridge News:
http://www.cambridge-news.co.uk/cn_news_cambridge/displayarticle.asp?id=469262
The full Nature journal story (must log in or pay):
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature08689.html