A New Understanding of an Old "Obesity Gene"

By -
As you know if you've been following this blog for a while, obesity risk has a strong genetic component.  Genome-wide association studies (GWAS) attempt to identify the specific locations of genetic differences (single-nucleotide polymorphisms or SNPs) that are associated with a particular trait.  In the case of obesity, GWAS studies have had limited success in identifying obesity-associated genes.  However, one cluster of SNPs consistently show up at the top of the list in these studies: those that are near the gene FTO.

As with many of the genes in our genome, different people carry different versions of FTO.  People with two copies of the "fat" version of the FTO SNPs average about 7 pounds (3 kg) heavier than people with two copies of the "thin" version, and they also tend to eat more calories (1, 2).  

Despite being the most consistent hit in these genetic studies, FTO has remained a mystery.  As with most obesity-associated genes, it's expressed in the brain and it seems to respond somewhat to nutritional status.  Yet its function is difficult to reconcile with a role in weight regulation: 
  • It's an enzyme that removes methyl groups from RNA, which doesn't immediately suggest a weight-specific function.
  • It's not primarily expressed in the brain or in body fat, but in all tissues.
  • Most importantly, as far as we know, the different versions of the gene do not result in different tissue levels of FTO, or different activity of the FTO enzyme, so it's hard to understand how they would impact anything at all.  
An important thing to keep in mind is that GWAS studies don't usually pinpoint specific genes.  Typically, they tell us that obesity risk is associated with variability in a particular region of the genome.  If the region corresponds to the location of a single gene, it's a pretty good guess that the gene is the culprit.  However, that's not always the case...

Read more »

Comments

Post a Comment

Popular posts from this blog

Feedback in Three Steps

By -
© 2003, Coert Visser As a manager you have just led a meeting. John brought forward a proposal to implement a Customer Relationship Management (CRM) system. He did this convincingly and enthusiastically but seemed to leave very little room for his colleagues Michael and Peter to respond. You want to talk to John about this...but how? Feedback is essential Giving and getting feedback is essential. The fact is, no matter how hard we try, we don’t always automatically perform excellent. We need information from others to know what is expected from us, how others perceive us, what we do well and what we should do better. Sometimes others have more expertise or skills, they look at your behavior from a different angle, and they may have access to different information. When feedback functions well in an organization, people are interested in signals about the effects of their behavior and they constructively correct each other. Fantastic! But now the less rosy daily practice.….. Feedback ca...
Read more

Esoteric Aspects of Edgar Cayce's Life

By -
Image
Gladys Davis, Hugh Lynn Cayce (right) and Harmon Hartzell Bro were among the members of this A Search for God study group meeting at A.R.E. Headquarters at Lake Holly in 1950.  This photo is from Edgar Cayce's Photographic Legacy (1978) compiled by David M. Leary. Some of Edgar Cayce's psychic (channeled) readings diagnosed and prescribed for people's physical ailments and disturbances.  These were described by Thomas Sugrue in There Is A River (1942) as presenting "cases, hundreds and hundreds of them, wherein the treatments have been faithfully followed, and the predicted results have been achieved." When information that was sought wasn't successfully forthcoming (such as locations for lost treasure or oil wells), Cayce and his associates were baffled.  These circumstances are chronicled in the book The Outer Limits of Edgar Cayce's Power (1971) by Edgar's sons Edgar Evans Cayce and Hugh Lynn Cayce.  One chapter, "Readings for...
Read more

Case Profile: Edgar Cayce

By -
Image
Edgar Cayce (1877-1945) became known as an American mystic and "psychic diagnostician" healer following hypnotic sessions where he would go into a trance and his body would be used as a channel.   The communicating Intelligence would speak in plurality, usually beginning a 'reading' with a statement such as "We have the body . . ." and finishing upon saying "We are through for the present."  I first learned about Cayce through reading Jess Stearn's biographies Edgar Cayce — The Sleeping Prophet (1967) and A Prophet in His Own Country — The Story of the Young Edgar Cayce (1974).  The first biography to be written about Cayce is There Is a River: The Story of Edgar Cayce (1943) by Thomas Sugrue, whose book heightened public understanding about Cayce during the final years of his life.  Sidney Kirkpatrick's Edgar Cayce: An American Prophet was published in 2000. Since 2005, I've occasionally studied portions of the extant 14,306 Cayce...
Read more