Fat Gene found to be associated with Obesity

Scientist finally identified the culprit behind the original gene responsible for obesity. This recent news published in the journal Nature. Earlier in 2007 several genomic studies highlights that FTO is strongly associated with the risk of obesity and type 2 diabetes. Then subsequent studies in mice revealed that there is a valid relation between the gene and the body mass. So several geneticist including the project head Dr. Marcelo Nóbrega, geneticist at University of Chicago clarified the doubts finally with the new identification of the gene which is actually responsible for obesity.

The finding:

The absolute finding began when there is significant mutation revealed in non-coding portions of FTO. Dr. Nóbrega found something amiss. The moment which made the researchers a pause was the regulatory regions contained some of the elements which are specific for lungs. The obvious question that comes up “Why are there regulatory elements that presumably regulate FTO in the tissue where it isn’t expressed?”

Long-range interactions in the IRX3-FTO locus. (Source: Nature)

Long-range interactions in the IRX3-FTO locus. (Source: Nature)

This was isn’t a red flag but provided the zeal in Dr. Nóbrega to find out what is the actual cause behind this. Instead some other regulatory gene might have been associated with FTO. Nóbrega presents his results in several meetings and conferences, and there people who had or have been working came up and suggested that there is obvious something wrong out there where the mystery yet to be resolved.

So Nóbrega and his team starts working to make their understanding into much wider platform to resolve the associated or nearby genes of FTO which is actually responsible in regulating it. IRX3 is the gene which is half a million base away from FTO whose expression of mutation actually get matched. IRX3 is a transcription factor – whose protein is involved in regulating the expression of other genes and known for its high expression in brain providing a consistent role in regulating energy metabolism and eating behavior.





Genemania online tool shows the co-expression map between FTO and IRX3

Genemania online tool shows the co-expression map between FTO and IRX3

They subsequently examined in mice, zebrafish and even on human cell lines where the identical results reveal that FTO is physically in contact with the promoter of IRX3.

The ultimate belief about GWAS

There is obvious a misconception about genome wide association studies (GWAS) that it just highlights about the association, and is the marker of the genome but actually don’t reveal which gene is actually affecting. Now the medication which was actually thought should be behind FTO has turned towards IRX3.


  • New contender of ‘fat gene’ found. Nature News. By Brian Owens. 12th March 2014.
  • Obesity-associated variants within FTO form long-range functional connections with IRX3. Smemo et al. 2014.

Further Reading: 



About Saumyadip

Science Communicator and Biologist. Keep interests in host-pathogen interaction research. Specifically bacterial infection mechanism, host infection evasion and immune susceptibility of host. PhD student at Academia Sinica Molecular and Cell Biology, Taiwan
This entry was posted in Molecular Biology and Genetics and tagged , , , . Bookmark the permalink.

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