A study published in Nature Genetics today has found new evidence for a link between the body clock hormone melatonin and type 2 diabetes. The study found that people who carry rare genetic mutations in the receptor for melatonin have a much higher risk of type 2 diabetes. The findings should help scientists to more accurately assess personal diabetes risk and could lead to the development of personalised treatments.
Previous research has found that people who work night shifts have a higher risk of type 2 diabetes and heart disease. Studies have also found that if volunteers have their sleep disrupted repeatedly for three days, they temporarily develop symptoms of diabetes. The body’s sleep-wake cycle is controlled by the hormone melatonin, which has effects including drowsiness and lowering body temperature. In 2008, a genetic study led by Imperial College London discovered that people with common variations in the gene for MT2, a receptor for melatonin, have a slightly higher risk of type 2 diabetes.
The new study reveals that carrying any of four rare mutations in the MT2 gene increases a person’s risk of developing type 2 diabetes six times. The release of insulin, which regulates blood sugar levels, is known to be regulated by melatonin. The researchers suggest that mutations in the MT2 gene may disrupt the link between the body clock and insulin release, leading to abnormal control of blood sugar.