In studies on mice which had been genetically modified to have the mutation, the mice consumed up to 80% more food than normal.
After a meal, hormones such as insulin and leptin should tell the brain that the body is full and should stop eating. The researchers showed that in the mutated mice the message was not being passed on from the hormones in the blood to the correct part of the brain.
One of the researchers Prof Baoji Xu said: “If there is a problem with the BDNF gene, neurons can’t talk to each other, and the leptin and insulin signals are ineffective, and appetite is not modified.”
He said the discovery “may open up novel strategies to help the brain control body weight” such as finding a “drug that can stimulate BDNF expression”.