A large gene study in the European population has identified 13 variants of the gene coding for the melatonin receptor that render it dysfunctional and then go on to increase the risk to Type 2 diabetes.
Melatonin, the hormone secreted by the pineal gland in the brain, controls the circadian cycle, adjusting the body clock to day and night. Its levels surge while sleeping. Earlier studies have shown that people with disrupted sleep patterns and night shifts have increased risk of Type 2 diabetes. “This has been known for a new study provides a genetic basis for it,” said Prof. Philippe Froguel, the lead author of the new study from Imperial Coll-ege London and Université Lille Nord de France.
South Asians in particular are very vulnerable to diabetes. In India there is prevalence of condition in 15 per cent of the population. It seems that in Asians, the secretion of insulin is less flexible than in Europeans. “That is why when Asians get fatter or older, there chances of getting diabetes is more than in Europeans,” Prof. Froguel explained. These dysfunctional variants and unhealthy sleep patterns might put South Asians at more risk.
The original work linking diabetes and abnormal sleep patterns because of disrupted melatonin levels has been confirmed in the South Asians but the sequencing results for now are restricted to Europeans. Prof. Froguel said that a paper showing the link between dysfunctional melatonin receptors and higher risk of Type 2 diabetes in South Asian population in the UK will soon be re-published.
The new study to be published in Nature Genetics clarifies that melatonin’s influence in motivating secretion of insulin, whose lack or unreceptivity leads to Type 2 diabetes. The finding could help shape new therapeutic strategies to tackle diabetes. Melatonin is administered to treat depression and insomnia and the receptors are established drug targets.