Researchers Identified Gene Mutation Tied to Severe Obesity
People are born with different body shapes and heights due to the genes they inherit. Since people cannot change these physical features, they can enhance them through weight loss or gain. Weight has often been perceived as something the individual can control through eating and exercising. Even though this is true, scientists have constantly identified obesity genes that explain why some people might be at a greater risk of obesity. For people with these genes, weight gain could be rooted in genetics and not behavior alone. In a new study, researchers discovered a new gene that could contribute to severe obesity.
"The history of obesity for many years has been one of blaming people for lack of self control," the lead author of the study, Dr. Joseph Majzoub said according to the New York Times. Majzoub is the chief of endocrinology at Boston Children's Hospital in the United States. "If some of it is due to a slow metabolism, that would completely change the perspectives of parents and patients. It would change the way we think of the disease."
In this study, the researchers analyzed a gene called MRAP2. The researchers discovered that MRAP2 acts as a helper gene in that its role in the brain is to signal the activation of another gene. This other gene has been tied to controlling appetite. After tying these two genes together, Majzoub and his colleagues theorized that the absence of MRAP2 could affect how appetite is controlled, leading to excessive eating. In order to test this hypothesis, the researchers used genetically altered mice that did not have the MRAP2 gene.
The researchers found that during the early stages of a mouse's life, which would be equivalent to childhood and adolescence, the genetically modified mice gained twice the amount of weight in comparison to their healthy siblings even though they all ate the same amount of food. Although the weight gain was shocking enough, the researchers noted that as the mice grew up, the genetically modified mice developed even bigger appetites. The researchers stated that the only way the obesity-prone mice could remain slimmer was to feed them 10 to 15 percent less food than their healthy siblings. The researchers found that the weight gain was mostly attributed to fat accumulation.
After making this discovery, the team contacted Dr. Sadaf Farooqui from the University of Cambridge, who was in charge of mapping out genes from severely obese children. There were 500 obese children in Farooqui's data set. After looking for this gene mutation, the researchers found that one child had a gene-disabling mutation while three other children had mutations that could have caused the gene to stop functioning. All of the healthy and normal weight children who acted as the control group did not have any mutations in this particular gene.
The researchers plan on studying how different types of mutations in the gene could contribute to weight gain. The study was published in Science.