Tuesday, July 19, 2005

Tight Jeans? Blame your Genes?

The BBC reported on Sunday that [s]cientists say they have discovered a gene linked to diabetes and obesity, offering hope for a diagnostic test in the article "DNA test for diabetes and obesity."

Faulty versions of the gene ENPP1 disrupt the way the body stores energy and handles sugar by blocking the hormone insulin. Children with faulty versions were obese at as young as five years old. The French and UK team told Nature Genetics that spotting the problem early and intervening could save lives.

Interesting, huh?

While inactivity and poor diets are much to blame for obesity and the metabolic problems that can lead to full-blown diabetes, the authors of the latest study say some people are genetically prone as well.

I don't know about you, but I think this may well turn out to be a "chicken versus egg" issue in the long-term. The reason - is the defect congenital (you're born with the defect) or is the defect from damage to the DNA later?

For one thing, the research cannot determine when or how the gene became defective at this point in time - just that those who are obese and/or have diabetes share similar defects in the gene (there wasn't one defect but eleven potential variations of defect on the same gene). This type of research holds much promise though - IF researchers investigate why there is a defect on this gene in the obese or diabetic.

While the media has been quick to offer this data up as evidence that a defective gene is potentially responsible for obesity and/or diabetes, I'd advise caution here before you throw up your hands and accept the idea that there is little you can do, it's in your genes.

Why?

We know from various other research of the genetic basis of disease and disorders that in many instances the defect found in the DNA is caused by something that has a cumulative effect on the body's ability to repair the damage. For example, as this article points out, [a]n accumulation of genetic damage to the DNA is how overexposure to sunlight can cause skin cancer and an overdose of radiation from X-rays can cause cancer in internal tissues like the thyroid gland. When oxidative damage occurs in genes that determine cell growth and when the mechanism that normally repairs such damage fails to work properly, the cell is no longer able to keep its growth in check and a malignant tumor results. There are already several other cancers that have been linked to genes that have lost their ability to repair defective DNA.

Also, given the narrow range of shared genes across the human genome, it appears unlikely that only particular populations are suddenly being born with a genetic defect while entire populations remain free of or have such small incidence of such a mutation. In the United States, Australia and Britain, obesity is skyrocketing while France, Italy and Spain remain relatively steady with obesity rates hovering for decades in the 6-10% range. Very similar environments, very different eating habits - very big reason to question how this genetic defect occurs and not assume it's congential.

Let's find the reason why this defect is happening in individuals who are obese and/or diabetic and work toward preventing this genetic defect from ever happening in the first place! Here are some things I'd love to see future research explore:
  • What is similar and different in the diets of those with the defective gene when compared with those that do not have it?
  • Do those with the defect have nutritional deficiencies in their diet?
  • Are there any environmental toxins those with the defect are exposed to that those without it are not?
  • Are there any dietary toxins those with the defect are exposed to that those without it are not?
  • Can a woman with the defect pass it on to her unborn child?
  • Can the damage be reversed by eliminating the cause (if one is found)?
  • Do those with the gene have an over abundance of any particular nutrient?
  • Do other markers exist that hint at damage occuring before it is evident on the gene?
  • Why are different defects found on the same gene in different people?
  • What percentage of obese and/or diabetic people have a normal gene?

2 comments:

  1. When I read this report I thought the same exact thing! But of course, you laid out the questions much more thoroughly. Great analysis!
    Adam;-)

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  2. Thanks Adam!

    This type of research is really compelling - something is going on and researchers are uncovering the genes that show a defect - and not just one type of defect, but in this case, eleven different variations of defect on the same gene. Personally I think continued research is going to show that something is damaging this gene disabling its ability to regenerate and repair - if the researchers can find what that "something" is, we can then work to prevent it!

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