To determine whether this microdeletion is involved in common obesity, the scientists studied the DNA of 16,000 European individuals of different weights. Among them, 19 were carriers of the chromosome 16 microdeletion. These 19 individuals all became overweight during their childhood and adolescence, and subsequently became obese as adults.

The researchers thus discovered that this defect, which generally concerns less than one in 1000 people, explains close to 1% of cases of common obesity (and 3% of cases for overweight people who also suffer from mental development disorders). In addition, the risk of carriers of a chromosome 16 deletion developing severe obesity is increased 50-fold (risk increase of 5000%).

Although the identity of the gene(s) responsible for obesity remains to be established, it is probable that these genes play a role in the development of the brain. This chromosome region is effectively known to be linked to the development of schizophrenia and autism, both diseases often complicated by obesity. These findings also confirm the link between obesity and neuropsychiatric diseases. In identifying common causes for these diseases, the scientists conclude that obesity may be a neurobehavioral disease.

This work opens up prospects for the development of new targeted preventive treatments, based on the identification of genetic causes of obesity, and even of other common diseases, such as diabetes and hypertension.

Source CNRS