To what extent is DNA-information transmitted by parents responsible for "bad" heredity and when does lifestyle play a decisive role? Often overweight, craving for alcohol, cancer, Alzheimer's and Parkinson's disease are attributed to "bad" heredity.
However, scientists and doctors note that the "guilt" of the DNA information received from the parents is exaggerated. The good news is that there is a good chance that the situation will change. What is known to science and medicine about the role of genetics and other factors in human he alth, we will learn from the Russian geneticist Dr. Dmitry Nikogosov - bioinformatician, head of the analytical department of a popular biomedical holding.
Dr. Nikogosov, does it mean that no matter how much we restrict ourselves in eating, exhaust ourselves in the gym, we will not become slimmer if in the family, as they say, everyone is "broad-boned" "?
- Let's not jump to conclusions, because so far scientists have been able to study only 2% information about those genes that directly affect obesity. There are many reasons for obesity, which occurs between the ages of 35 and 70: impaired function of the endocrine system, lifestyle, eating behavior and genetics. The contribution of genes received from parents is estimated to be in the range of 40-70%.
Here is a concrete example: we once examined the DNA profile of a colleague of ours, who was of normal weight, but very much wanted to know if she should be worried about obesity, since all her relatives had luscious forms. Analysis from the complete genome showed that she had nothing to fear. It was later revealed that her parents had been diagnosed with an eating disorder, which actually led to her being overweight.
And another example with a young man from a village who has moved to Moscow a few years ago. His genetic test proved that he was prone to being overweight. The young man admitted that in his area they prefer rich meals, barbecues, steaks and are not into sports at all. After some time, we contacted him to find out how his life changed after the DNA analysis.
He boasted that he got serious about running and weightlifting, changed his eating habits and felt great… The bottom line is clear. In general, in 5 years of observations of people on whom we conducted a genetic test, in only 30% of cases the study showed mutations in the genes known to science, related to the risk of obesity.
And how justified is the notion that alcoholism is often "written in the genes"?
- The likelihood of alcoholism is related, on the one hand, to how the body processes alcohol. On the other hand, lifestyle also plays a role: whether a person drinks every night or only on weekends; how often does he participate in such "mohabbats", how do they go, are there drinkers among relatives and friends, etc.n. If even after a small dose of alcohol your face suddenly turns red and you feel heart palpitations, alcohol is not for you.
The same applies to the speed of getting drunk: if a man or woman gets drunk very quickly and does not experience a hangover, there is a high probability of alcohol addiction. Because the brain gets used to it and it is not accompanied by a hangover "whip". After all, each person makes the choice to drink or not. He is most significantly affected by unfavorable surroundings, life problems, etc. Already in the 19th century, it was proven that the acquired tendency to abuse alcohol is not inherited.
Oncologists often advise us to pay attention to family history in this regard. How big is the chance to avoid cancer if there is a hereditary predisposition to it?
- Up to a third of cancer patients get cancer "by inheritance from parents". If there was a hereditary form of breast cancer in the family, the woman should be alert.Unfortunately, the probability of such a gene mutation being passed from mother to daughter is very high. The most striking example of this is the story of Angelina Jolie, who inherited hereditary breast and ovarian cancer syndrome.
The presence of cancer patients in the family is a reason for a genetic test. We were once approached by a young man, and we found in him a mutation in the BRCA1 gene capable of causing prostate or pancreatic cancer. He was very surprised, but in the process of consultations with a geneticist, it became clear that his grandmother and grandfather died quite early. That is, the cancer failed to attack them.
Subsequently, we tested all his relatives: mother, father, brother and sister. It turned out that the man had inherited this mutation from his father. Now this young man and his father are examined annually by an oncologist and lead a he althy lifestyle to minimize the risk of developing cancer.
It is important to note that more than half of cancer cases are not directly related to heredity.The reasons for them are in the way of life, the influence of external conditions and the accumulation of mutations with age. If, for example, you are often in the sun and do not protect yourself from ultraviolet radiation, the probability of melanoma is high. Frequent visits to the beaches provoke skin cancer.
To what extent do genes influence the occurrence of ischemic heart disease?
- IHD ranks first among the causes of premature death worldwide, and most often such a diagnosis is made in people aged 50 to 85 years. The risk of developing ischemic heart disease is influenced by a combination of genes responsible for the work of the heart and blood vessels, the level of cholesterol in the blood, coagulation and other indicators. But it cannot be said that this is exclusively a hereditary story. Lifestyle and concomitant diseases play a decisive role.
We examined the DNA of a young man in whose family two generations of relatives had died of heart attacks.It turned out that the disease was indeed inherited in them and may also appear in our patient. We recommended that he see a cardiologist regularly and make lifestyle changes to lower this risk. For this purpose, he needs to give up products with trans fats, add more foods rich in omega-3 fatty acids to his menu, stop smoking and start moving more actively.
Can you also comment on heredity in Parkinson's disease?
- It has been scientifically confirmed that Parkinson's disease develops due to genetic predisposition. From 10 to 15% of cases of the disease are related to genetic changes. Scientists know the genes LRRK2, PARK2, PARK7, PINK1, SNCA and many others, which are responsible for the risk of developing Parkinson's disease. Most often it manifests itself in old age: in 23% of cases after 80 years; in 21% - at 70 years old and in 15% - at 60 years old.
The disease makes itself known when there is a feeling of stiffness in the limbs, when the hands begin to tremble, movements slow down and coordination is impaired.Injuries contribute to the onset and progression of this disease. An example of this is the world-famous boxer Muhammad Ali, who in his old age fell victim to an aggressive form of Parkinson's. The reason – the constant and systematically repeated blows during the matches. Parkinson's disease can be delayed and regressed over time if you do sports, if you avoid the effects of pesticides and head trauma.
Nowadays, genetics makes it possible to detect the risks of developing hundreds of multifactorial diseases and thousands of hereditary pathologies. Thus, the disease will not be allowed to take over the life of the person and his family. And the genetic test helps to increase the efficiency of medical care and to select personalized programs for the treatment of diseases. But nevertheless, remember that in most cases the role of lifestyle is much greater and often turns out to be decisive.