Genetic Links to Childhood Obesity Discovered
Author: Daniel Weiss, Senior Editor
Two gene variants associated with increased risk of childhood obesity have been discovered, raising the hope that drugs can be developed to treat the condition.
An international team of researchers has discovered at least 2 genetic variants that are associated with increased risk of developing childhood obesity—raising the possibility that medications can be developed to help prevent the condition. The researchers, who were part of a collaborative group called the Early Growth Genetics Consortium, published their results online on April 8, 2012, in Nature Genetics
Previous research has identified genes associated with adult obesity and extreme childhood obesity due to rare diseases, but until now little has been known about the genes implicated in regular childhood obesity. To investigate these genetic links, the researchers performed a meta-analysis of 14 studies including 5530 individuals whose body mass index (BMI) was in the top 5 percentile and 8318 controls, whose BMI was in the lower 50 percentile, all of European ancestry.
The meta-analysis turned up 2 gene variants that had a significant association with early-onset obesity—1 near the OLFM4 gene on chromosome 13, and 1 near the HOXB5 gene on chromosome 17. Both gene variants continued to show an association when 2 extreme childhood obesity cohorts were added, which included 2214 individuals whose BMI was in the top 0.5 percentile and 2674 controls. Including these cohorts, the gene variant near the OLFM4 gene was associated with a 22% increased risk of childhood obesity, and the gene variant near HOXB5 was associated with a 14% increased risk of childhood obesity. Both associations were statistically significant. The gene variants are also associated with increased risk of adult obesity, although not as strongly, indicating that their primary effect is expressed early in life.
The newly discovered gene variants seem to play a role in the intestine, possibly involving the makeup of gut bacteria, although their exact role in causing obesity is unknown. The researchers hope that knowledge of the genetic variants associated with childhood obesity will aid in the development of drugs or other therapies to combat it. According to the Centers for Disease Control and Prevention, childhood obesity in the United States has more than tripled in the past 3 decades. As of 2008, almost 20% of children 6 to 11 years old and 18% of adolescents 12 to 19 years old were obese. Individuals who are obese during childhood face a range of disadvantages in adulthood, including increased risk of mortality.
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