Researchers from Oxford University and Babraham Institute in Cambridge, U.K., have discovered the first gene to cause an increased sensitivity to the hormone insulin. This new discovery may pioneer promising drugs for treatment for diabetes.
According to lead study author Dr. Anna Gloyn, of the Oxford Centre for Diabetes, Endocrinology and Metabolism at the University of Oxford, insulin resistance is a key component in type 2 diabetes.
"Finding a genetic cause of the opposite - insulin sensitivity - gives us a new window on the biological processes involved. Such understanding could be important in developing new drugs that restore insulin sensitivity in type 2 diabetes," Dr. Gloyn said.
The gene, PTEN, is involved in the process for growth and metabolism. Knowing the gene's function, researchers were interested in understanding the metabolic profile of people with Cowden syndrome, a rare disorder characterized by multiple noncancerous, tumor-like growths called hamartomas.
Researchers conducted glucose tolerance tests with 15 patients who suffer from Cowden syndrome and 15 individuals who were used as the control group. It was observed that patients who suffered from Cowden syndrome had higher insulin sensitivity, due to an increased insulin signaling pathway. Because the body mass index of patients with Cowden syndrome appeared greater than the controls, researchers carried out a comparison of a larger control group involving more than 2,000 individuals.
The study demonstrated patients with Cowden syndrome had higher levels of obesity compared to the control group. The additional body weight was caused by extra fat.
"This was a surprise. Normally insulin sensitivity goes with being lean," Professor Fredrik Karpe said.
Dr. Gloyn believes the mutations that are inactivate in the PTEN gene result in an increased cancer risk and obesity, but also increase insulin sensitivity, which may protect against type 2 diabetes.
"While there are promising research avenues to pursue here, in the meantime the best way to avoid diabetes remains exercising more and eating less," she said.