Melanocortin deficiency is rare in humans, Hochgeschwender said. Mice and humans who lack melanocortin also have a pigment deficiency, which results in dirty-blond hair in mice and red hair in people. One is the appetite goes down, so not that much food is taken up the next time around. In a genetically engineered mouse with no melanocortin, however, the appetite remains unaffected despite overeating. Also, the body tends to store the extra food as fat rather than burning it up.
Incoming fat is taken up and is stored in the body, resulting in overweight.
Even though the body is signaling to the brain that there is too much fat on board, the brain does not have the signal to respond and stop the further uptake and storage of fat. In the future, patients who lack the POMC gene potentially could benefit from an anti-obesity drug that provides melanocortin. Obesity typically involves an imbalance of food intake and energy output. Most of the current anti-obesity drugs work on appetite suppression. Benefits of this research are twofold, she said.