Scientists say that there are at least 79 "syndromes" of obesity

When it comes to obesity, everything is much more complicated than it seems at first glance. A new survey of studies in Canada shows that obesity has at least 79 different forms associated with human genes, and many of them are very rare.

Obesity caused by a malfunction in the work of genes

Although lifestyle factors such as diet and physical activity play an important role in obesity, studies have shown that there is also its genetic component. Therefore, in a new survey, researchers focused on the types of obesity that can be caused by genes. They examined over 160 studies on genetic forms of obesity. Previous reviews have shown that there are 20 to 30 different types of obesity, - the authors write.

But in the new survey, researchers identified a total of 79 genetic "syndromes" of obesity. By syndromes are meant conditions that are the results of genetic changes and cause a person to obesity among other symptoms. For example, one of such "syndromes" of obesity, which has long been known, is a genetic condition called Prader-Willi syndrome. According to the survey, people with this syndrome may experience obesity, developmental delay, growth hormone deficiency, excessive hunger, and they are prone to abnormally voluminous consumption of food.

According to another review, other syndromes may be associated with mental deficiencies, facial abnormalities and other symptoms.

The review says that out of 79 syndromes 43 have not received a name. In addition, scientists fully calculated the main genetics for only 19 syndromes. Thus, they reported a partial understanding of the basic genetics, according to the survey. Nevertheless, the researchers identified 22 syndromes, of which scientists previously did not know anything.

"A clearer understanding of the genetic causes of these syndromes can not only improve the lives of people suffering from these mutations, but also help us better represent genes and molecules that are important in obesity," says senior survey author David Meir, associate professor of health research methods At McMaster University in Ontario, in a statement.

Results of studies on twins

Studies conducted on identical twins have shown that obesity by 40-75 percent depends on genetic conditions, researchers said in a survey published on March 27 in Obesity Reviews. In it, researchers focused on those types of obesity that are associated with one gene and cause syndromes (syndromes, by definition, include a set of symptoms.)

The researchers noted that two other groups of genetic obesity disorders were not included in the review: the types of obesity that are associated with multiple genes, and those that are associated with only one gene but do not cause syndromes.

Prevalence

The review also considered how widespread these forms of obesity are, but estimates were only available for 12 of them. Indeed, these syndromes are rare, their prevalence is less than 1 case per 1 million people. One of the disorders, for example, called Alström syndrome, was found in about one person out of 900, according to the National Medical Library.

The authors noted that they hope that their work will increase the effectiveness of research on genetically determined obesity syndromes.