Scientists Narrow in on Genetic Cause of Obesity
April 13, 2006 — -- It's no secret that a combination of greasy fast food and couch potatolike behavior has contributed to America's obesity epidemic.
Many scientists, however, have also wondered whether something else is involved: Could there also be a genetic explanation?
Research is showing this may indeed be the case for some people. In today's issue of the journal Science, researchers explain how they have found a variation, or "misspelling," of DNA located near a gene that normally affects fat metabolism.
"It's the first common genetic variant to be associated with obesity," said Dr. Michael Christman, a lead researcher and chair of the Department for Genetics and Genomics at Boston University.
DNA contains genetic material, or instructions, for cells throughout the body. Genes are pieces of DNA that carry out these instructions.
Researchers discovered this variation after analyzing DNA samples collected from 9,881 people over a 24-year span. They also discovered that people of different racial, ethnic and age groups who had the same misspelling had an increased risk of obesity.
"The strength of this study was that we were able to replicate the data in different populations," said Dr. Alan Herbert, a lead researcher of the study and assistant professor of genetics and genomics at Boston University.
Ten percent of the population has this misspelled DNA, scientists estimate, and those who have it also have a 30 percent to 50 percent increased risk of becoming obese.
Obesity is considered a risk factor for a number of diseases such as hypertension, diabetes and stroke. In recent years, obesity rates have increased drastically in both adults and children.
The study could lead to a better understanding of what role genetics plays in obesity.
"We have not understood what the common genes are that predispose us to the disease," Christman said.
Genetic researcher Dr. Teri Manolio, of the National Human Genome Research Institute, said the study was one of the best she'd seen on the topic.
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