The Corpus Callosum

is from Medpage Today, which often carries the same things as Medscape,
but does not require registration (hint, hint).

They report on the finding of a genetic variant that increases the risk
of obesity.  the more copies of the allele, the greater the
risk.  The association was found when researchers at were
looking for a genetic basis for type II diabetes mellitus.
 They thought they found one, but when they controlled for
body mass, the association disappeared.  So the allele is not
a direct cause of diabetes, but does increase the risk by increasing
the risk of obesity.

The article is rather curious, because it goes on to talk about some of
the not-significant implications of the finding.  They miss
the significant ones.

Variant Increases Obesity Risk

Michael Smith, Senior Staff Writer, MedPage Today

12, 2007

England, April 12 — The first clear genetic link to obesity for the
common man or woman may have been nailed down by researchers here.

British team that discovered the obesity-linked gene variant doesn’t
understand what it does or how it contributes to extra poundage. But
the investigators are sure of the association.

studies involving nearly 40,000 Europeans, the variant of a
little-known gene on chromosome 16 increased the risk of being obese by
up to 67%, according to Andrew Hattersley, D.M., of the Peninsula
Medical School.

16% of adults with two copies of the variant weighed on average about
three kilograms (6.6 pounds) more than counterparts with no copies, Dr.
Hattersley and colleagues reported online today in Science…[Frayling
TM et al. “A Common Variant in the FTO Gene Is Associated with Body
Mass Index and Predisposes to Childhood and Adult Obesity.” Science
2007; doi 10.1126/science.1141634.]

they added that the finding shouldn’t change the way doctors think
about obesity…

McCarthy added there is no need to develop a genetic test for the gene
variant, since it is “quite easy to see if someone is overweight.”…

Hattersley noted, “The best way forward for managing obesity is still
what it was” — exercise and lifestyle changes….

They go on to say that the function of the gene is not known.
 That is the interesting part.  What does this gene
do?  How is it regulated?  Is there some pathway for

With early discoveries such as this, there typically is no immediate,
practical significance.  What is
interesting is the implication for basic research.  What
follow-up studies are planned?  How will they be carried out?
 Does this change their theoretical understanding of anything,
or suggest new hypotheses?  That is what I want to know.


  1. #1 Karen Ventii
    April 13, 2007

    This is quite interesting.

    With complex conditions like obesity there are usually many factors (extrinsic and intrinsic) that are involved. I wouldn’t be surprised if there is more that one gene involved in the genetic predisposition to obesity.

    Is this FTO gene part of a family? Did they address the possibility of other genes being involved?

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