Common gene variants linked to obesity

NEW YORK (Reuters Health) -
Researchers have identified new
genetic variants that influence the risk of obesity and insulin
resistance, a precursor to diabetes, according to findings from
two studies published online this week.

In the first of the two genome-wide association studies, a
research team headed by Dr. Ruth J. F. Loos, from Addenbrooke's
Hospital in Cambridge UK, analyzed data from 16,876 people of
European descent.

The investigators not only confirmed prior research linking
variants in the FTO gene with obesity, but they also identified
a strong association with genetic variants near the MC4R gene.
The MC4R gene regulates energy levels in the body by
influencing how much we eat and how much energy we expend or
conserve. Mutations in this gene are the most common genetic
cause of severe obesity that runs in families.

The findings by Loos and colleagues, which were later
confirmed in 60,352 adults and 5988 children, showed that the
presence of the MC4R risk variant increased the odds that a
child would be obese by up to 30 percent. An analysis of data
from 660 families revealed that "over transmission" of the risk
variant was common among obese offspring.

"Several groups had shown that rare, highly disruptive
variants in the MC4R gene were responsible for very severe,
genetic forms of obesity: this collaboration (by many
international groups) has uncovered more common variants that
affect more people," Loos said in a statement.

In the second study, an investigation of 318,237 single
letter changes, or SNPs, in the DNA of over 14,000 subjects of
Indian Asian and European descent, Dr. Jaspal S. Kooner, from
Imperial College London, and colleagues linked a gene sequence
variant near the MC4R gene with increased waist circumference
and a tendency to become insulin resistant, which can lead to
type 2 diabetes.

Two copies of the risk variant added roughly 2 cm to waist
circumference and increased insulin resistance by about 10
percent, the results show.

"A better understanding of the genes behind problems such
as diabetes and cardiovascular disease means that we will be in
a good position to identify people whose genetic inheritance
makes them most susceptible," Kooner said in a written
statement.

"We can't change their genetic inheritance. But we can
focus on preventative measures, including life-style factors
such as diet and exercise, and identifying new drug targets to
help reduce the burden of disease," Kooner added.

source:news.yahoo.com

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