obesity-arthritis-genes-rheumatologist-delhi-indiaA genetic study reveals that chemical changes to our DNA may make us obese.

It is known that sometime in life, methyl chemical groups attach to some of a person’s DNA and can act as dimmer switches. Some of these genetic changes are genetically determined. Others appear to happen very early in life and are pretty much permanent. Still others happen through the life span, and may or may not be permanent. Identical twins have identical DNA when they are conceived but as they age, the chemical attachments to their DNA grow more and more different.

Can these changes make a person more or less vulnerable to disease? To find out, Feinberg and colleagues looked at 4.5 million DNA sites in 74 elderly Icelandic people participating in a gene study. Participants gave blood samples twice, with 11 years between measurements.

Some of the people in the study were obese. Others were not. Feinberg and colleagues found 13 changes that were much more common in the obese people. Four of these changes remained the same in the two tests 11 years apart. The changes were in genes scattered across the human genome.

The researchers suggest that if their findings are confirmed — and if the changes begin in childhood and remain stable — tests might be able to identify children at highest risk of growing up obese.

Feinberg and colleagues report their findings in the Sept. 15 online issue of Science Translational Medicine.