Obesity: Gene mutations linked
2008-12-15 07:40
Washington - Researchers have identified
six new gene mutations linked to obesity and said on Sunday
they point to ways the brain and nervous system control eating
and metabolism.
"Today's findings are a major step forward in understanding
how the human body regulates weight," Dr Alan Guttmacher,
acting director of the National Human Genome Research
Institute, said in a statement.
"This study essentially doubles in one fell swoop the
number of known and replicated genetic factors contributing to
obesity as a public health problem," added Dr Kari Stefansson,
Chief Executive Officer of deCODE Genetics of Iceland and one
of the researchers.
The international team analysed 300 000 one-letter
mutations in the genetic code known as single nucleotide
polymorphisms or SNPs in more than 30 000 people from Iceland,
the Netherlands and the United States.
They cross-checked their findings in 40 000 people from
Denmark and the United states.
They found that variations in six genes - TMEM18, KCTD15,
GNPDA2, SH2B1, MTCH2 and NEGR1 - were strongly associated with
a height-to-weight ratio known as body mass index or BMI.
"Today's findings are a major step forward in understanding
how the human body regulates weight," said Guttmacher, whose
institute, one of the National Institutes of Health, helped
fund and conduct the study.
"One of the most notable aspects of these discoveries is
that most of these new risk factors are near genes that
regulate processes in the brain," added Stefansson, whose
company hopes to sell genetic tests based on such discoveries.
Diet and metabolic factors
"This suggests that as we work to develop better means of
combating obesity, including using these discoveries as the
first step in developing new drugs, we need to focus on the
regulation of appetite at least as much as on the metabolic
factors of how the body uses and stores energy," Stefansson
said.
"These new variants may point to valuable new drug
targets," he added.
Nearly a third of US adults are considered obese with a
BMI of 30 or more.
Obesity is associated with more than 100 000
deaths each year in the US population and trends are similar
in many other countries.
"We know that environmental factors, such as diet, play a
role in obesity, but this research further provides evidence
that genetic variation plays a significant role in an
individual's predisposition to obesity," said the genome
institute's Dr Eric Green.