New "obesity genes"
Rare genetic causes of obesity have been classified
Anna Stavina, XX2 century
Previously, it was believed that about 20 genetic features could be the cause of obesity. However, a new study has shown that there are actually much more of them. The results of the work were published on Monday in the publication Obesity Reviews (Kaur et al., A systematic review of genetic syndromes with obesity).
Canadian scientists have identified and described 79 genetic syndromes, one of the main symptoms of which is obesity, a condition in which the body mass index (BMI) is 30 kg/m2 or more. Although the work was devoted to the search for rare hereditary syndromes, its authors are confident that it can be useful to millions of people around the world who have lost control of their own weight for reasons related to genetics.
"In the study, we focused on the monogenic causes of obesity," says study leader David Meyre, associate professor at the Michael G. DeGroote School of Medicine at McMaster University in Ontario. We are talking about the so–called "Mendelian diseases" - certain combinations of genes that cause the disease with 100% probability. An example of such diseases is, for example, Huntington's chorea, a disease of the nervous system that affects both the ability to move normally and cognitive abilities.
Monogenic syndromes that can cause overweight are very rare. Together, they are the cause of approximately 0.5% of cases of obesity in the population, and people with such diseases are born with a frequency of one in a million. But such syndromes are more dangerous than alimentary obesity – they are also associated with cognitive impairments, kidney diseases and heart defects. However, "normal" excess weight is also not harmless – it can cause heart disease, type 2 diabetes and some types of cancer. Today, obesity is one of the leading causes of premature death in developed countries.
In the course of the work, the authors analyzed 161 articles and found references to 79 different genetic syndromes associated with obesity. Diagnostic techniques have already been fully developed for 19 of them, so you can confirm the presence of the disease with a simple test. Another 11 are only partially described, 27 have only identified the part of the chromosome in which the mutation is present. For the remaining 22 syndromes, neither the genes nor their location in the chromosomes have been determined.
"The detection of these genes is very important for families [in which the disease is detected]," explains Meir. Some more common genetic syndromes are well corrected with the help of hormone therapy – it reduces the severity of symptoms. If geneticists identify the genes responsible for the development of obesity and other manifestations of the disease, doctors will be able to find a suitable treatment.
"We also hope that our work will help doctors in diagnosing these syndromes," adds Meir. During his entire professional life, a doctor may encounter only one or two patients suffering from such diseases. Due to lack of information and clinical experience, the disease may remain unrecognized, and the patient will not receive the necessary treatment.
In addition, the results of the new work may lead to a better understanding of the genes and molecules associated with the development of obesity in the general population.
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28.03.2017