Genetic mutation increases risk of Type 2 diabetes?

A new study released by Imperial College London suggests that a faulty gene may increase the risk of developing Type 2 diabetes.
Written by Charlie Osborne, Contributing Writer

Individuals that carry mutated version of a 'body clock' gene are at increased risk of developing Type 2 diabetes, a new study has suggested.

The research, conducted by a team from Imperial College London, has been published in the journal Nature Genetics. It suggests that there may be a link between the body's sleep cycle, which is governed by the hormone melatonin, and the onset of Type 2 diabetes.

Previous studies have suggested that those who work night shifts have a higher risk of developing the disease, as do those who endure disrupted sleep patterns -- the volunteers involved in this research resulted in developing the symptoms of diabetes after three days.

Although T2D is often linked to obesity and lifestyle choices, and therefore it is possible to create tenuous links between jobs that require disruption (such as shift work or on-call jobs) and that may also affect food choice (what is available at the time rather than substantial, regulated eating), it has also been suggested that genetic mutations may be to blame.

Melatonin is responsible for controlling a body's sleep cycle and waking -- therefore inducing drowsiness and lowering body temperature. It is often taken as a supplement by those who suffer from jet-lag.

This research paper involved a team examining the gene's effects at several institutions in the UK and France. 7,632 Europeans were examined, in order to find links between unusual variants and disease risk. The scientists found 40 variants associated with Type 2 diabetes in total, four of which rendered the MT2 gene receptors incapable of responding adequately to melatonin production or binding. These links were later boosted with an additional sample of 11,854 people (8,153 individuals with Type 2 diabetes and 10,100 controls).

The research focused on the gene MT2, which controls molecular cell receptors in order to allow melatonin to work. After considering the link, human cell samples were tested in relation to mutated gene effects in laboratory settings.

The investigation of all 40 mutations found that:

  • 14 were non-functional and rare
  • 4 were very rare, and resulted in complete loss of function and melatonin binding.

Among these variants, the 4 rarest mutations contributed to Type 2 diabetes risk.

According to the research, if you are a carrier of one of four rare mutations, then MT2 increased the risk variables of developing Type 2 diabetes up to six times. If the gene MT2 does not perform correctly, it is thought that insulin is not released properly, which in turn leads to irregular control of blood sugar levels.

Professor Philippe Froguel, who led the study, said:

"We found very rare variants of the MT2 gene that have a much larger effect than more common variants discovered before. Although each mutation is rare, they are common in the sense that everyone has a lot of very rare mutations in their DNA. Cataloguing these mutations will enable us to much more accurately assess a person's risk of disease based on their genetics."

The findings may help scientists, and therefore doctors, more accurately assess personal risk of Type 2 diabetes within individuals, and may lead to further development of personalized treatments.

More than two million people are known to suffer with Type 2 diabetes in the UK, and an estimated one in twelve Americans.

Image credit: Alden Chadwick/Flickr

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