Researchers: Deciphered epigenetic causes of obesity

Epigenetic variant involved in the development of obesity
The cause of obesity and obesity is often in the genes. In addition to the genome itself, so-called epigenetic variants, i.e. changes in the environment of the genome, are to be assessed as possible causes of obesity, according to the results of a current study at the Charité - Universitätsmedizin Berlin. A certain epigenetic variant leads to a significantly increased risk of developing overweight, the researchers report.

In their study, the scientists were able to demonstrate that not only genetic factors but also so-called epigenetic variants influence the risk of obesity. "Accordingly, an epigenetic variant on the proopiomelanocortin gene (POMC gene), which plays a special role in regulating body weight, leads to an increased individual risk of becoming overweight in the course of life," said the Berlin Charité. The researchers published their results in the journal "Cell Metabolism".

Body weight regulation genetically influenced
In previous studies with identical twins, there were already indications that a high genetic part is involved in the regulation of body weight, the researchers report. However, the genetic variants discovered so far only explained a small part of the cases of obesity. "We therefore looked into the question of whether, apart from genetic changes, epigenetic changes could also play a role in the regulation of body weight," explains Dr. Peter Kühnen from the Institute for Experimental Pediatric Endocrinology at the Berlin Charité.

POMC gene with higher methylation intensity
The so-called epigenetics describes variants that can regulate the function of a gene without the gene sequence in question itself being changed. "Probably the most stable epigenetic change is the so-called DNA methylation, the coupling of a chemical compound, a methyl group, to the genetic material," explain the scientists at the Berlin Charité. To what extent the epigenetic variants have an influence on the regulation of body weight has so far been largely unexplored. In the current study, the researchers were now able to demonstrate that "obese children and adults had a significant proportion of a certain part of the POMC gene at a higher methylation intensity than normal-weight people", reports the endocrinologist Dr. Bold of the results.

Influence of the fathers on DNA methylation
Furthermore, according to the researchers, the same methylation variant was found in the POMC neurons in the brain of deceased, overweight people. The epigenetic change after birth was also found in blood cells and remained unchanged during the first years of life, according to the Charité. In addition, the scientists were able to observe a paternal influence on this POMC-DNA methylation in the child, reports the Charité.

One risk factor among many
The epigenetic variant is not the main cause of obesity, but only one potential factor among many. But the changes on the gene that is important for the regulation of body weight seem to lead to the risk of developing excess weight being significantly increased, the researchers explain. In further studies it should now be clarified how this epigenetic variant of the gene arises and how, for example, the influence of the father on the degree of DNA methylation in the child can be explained. (fp)

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