http://www.usatoday.com/news/health/story/2012-04-09/childhood-obesity-genes-variants/54082720/1?csp=34news
Study finds gene variants behind childhood obesity risk
By Nanci Hellmich, USA TODAY
Scientists have discovered 2 gene variants that appear to play a
critical role in the development of common childhood obesity,
according to a large genetic study released Sunday. The discovery
could eventually lead to treatments and specific lifestyle advice
for heavy children. Although previous research isolated gene
variants that impact extremely obese children and obese adults,
this is the most extensive effort yet to pinpoint those involved
in more typical childhood obesity. The latest findings are part
of a large analysis of genetic studies conducted on thousands of
children from the USA/Europe/Australia. Experts have long known
that both genetics & enviro factors play a role in development of
obesity. This research "robustly" shows these 2 gene variants
predispose some children to obesity more than others, said Struan
Grant, associate director of the Center for Applied Genomics at
The Children's Hospital of Philadelphia. "Childhood obesity is
partly in your genes. It's partly your lifestyle."
The gene variants appear to increase the risk of obesity in the
first few years of life — even in children as young as 2, said
Grant, the lead author of the study, published online in Nature
Genetics. "We don't know how many gene variants are involved in
childhood obesity, but we've identified the variants with the
largest effect," he said. Exactly how these gene variants work
isnt known, but "when we look at the scientific literature, they
may be operating in the intestine," Grant said. "It may have
something to do with the bacteria in the gut." "Obesity is the
result of a complex interplay among biological/behavioral/cultural/
enviro/econo factors," said Karen Winer, a program director at
the Eunice Kennedy Shriver Nat'l Inst of Child Health & Human
Development, part of the N.I.H., which helped fund the new study.
"Obesity is recognized as a highly heritable condition, but the
underlying genetic factors associated with common obesity, until
today, have remained a mystery," she said.
Currently, about 1/3 of kids are obese/overweight. Roughly 17% of
children & adolescents ages 2-19 are obese. Kids are considered
obese if they're in 95th percentile or above, based on standard
national pediatric growth charts. Grant & colleagues analyzed
genes contained in the world's largest collection of DNA from
obese children & slim children, found in nearly 2 dozen studies
covering more than 20,000 children of European ancestry. "We're
going to continue to look for more genes, & the more info we get,
the more accurately we will eventually make lifestyle decisions
for children based on their genetic makeup," Grant said. "This is
giving us new insights to the biology of obesity, which could
potentially one day lead to both more efficient medicines & more
specific diet/exercise advice for kids who are genetically pre-
disposed to obesity."
Ruth Loos, dir. of the Genetics of Obesity & Related Metabolic
Traits Program at Mt Sinai School of Medicine in New York, wasnt
involved in this study but says this research, like previous work,
"shows that genetic susceptibility to obesity begins at an early
age. However, this doesnt mean that those who are genetically
susceptible are destined to become obese adults, because healthy
lifestyle remains an important factor that can reduce one's
genetic susceptibility." This study suggests "that trying to fight
this genetic susceptibility should start early in life," Loos said.
She said gene research may provide insight into the biological
pathways that contribute to obesity. "If some of these genes turn
out to be drug-able targets, then maybe this could lead to new
medication. But that is indeed years away, it will require much
more detailed physiological research," Loos said.