The doctor told why genetic tests are needed and whether they should be done
Genome testing makes it possible to "calculate" dangerous hereditary diseases - newborns in our country are already tested for 36 rare pathologies. Why else are such tests needed? Can they be used to adjust the diet to protect against future diseases? About common myths in this area told the doctor-geneticist, head of the Center for Clinical Research Nebbiolo in Tomsk Oksana Makeeva.
Myth 1. Many people say: it is scary to do a genetic passport because I may learn about a fatal disease or something I don't want to know about.
As a rule, people who do a large genetic test for 600-700 thousand points of the genome (often called "genetic passport") are older than 20 years old. By that age, the most dangerous diagnoses of hereditary diseases would have already been known about - they tend to manifest themselves in childhood.
The most serious thing that can be identified is the status of a healthy carrier of a gene for a rare disease or high risk of developing diseases with hereditary predisposition. But it is better to know about the carriage of genes for rare diseases - then you can test your partner for mutations in a similar gene, and based on the result to plan the birth of a child. If it turns out that both partners are carriers, it will be possible to use IVF methods and make preimplantation diagnosis with the selection of a healthy embryo. If the partner does not have mutations in "your" gene, you can forget about the carrier and without fear of planning a pregnancy.
As for the high risks of diseases with hereditary predisposition (this category includes diabetes, heart attack and hypertension) - it is also better to have such information: after all, in respect of most diseases there are preventive measures and rules, and they can be observed. These are, for example, lifestyle changes, dietary changes, taking medication or frequent preventive check-ups.
Almost every "unfavorable" genetic variant has a downside. If it became widespread in the population, it means that it gave our ancestors an advantage to survive and leave offspring in life-threatening conditions. For example, obesity genes allowed us to store nutrients in the body in the form of fat and to endure long periods of starvation. Neuroticism genes kept our forebears awake at the entrance to the cave, causing them to be more precautionary and consequently live longer than others and leave more offspring, while spreading the neuroticism gene.
Myth 2: Father and mother make the same contribution to the child's genetic material
The child at conception receives from the mother and father the same number of chromosomes - 23 each. Based on this, everyone believes that the contribution of the parents is equal. But this is not entirely true. With the mother's egg, the child receives not only a set of chromosomes, but also her extra-chromosomal heredity, namely mitochondria, which have their own genetic apparatus and are transmitted only from mother to child. Mitochondria are the energy "stations" of the cell. The brain is the most energy-consuming organ. Now there is a boom in the study of mitochondrial dysfunction, and many diseases, especially those related to brain and nervous system activity, are directly linked to the quality of mitochondria. Therefore, the mother's contribution to the genetic health of the next generation is greater still.
Myth 3: Genetic tests are needed to have individualized nutritional recommendations
Genetic tests provide individualized nutritional recommendations only for certain types of food intolerances: for example, intolerance to lactose (milk sugar), casein (cow's milk protein), gluten, alcohol, coffee metabolic rate. An increased need for certain vitamins, amino acids, and other nutrients can also be detected.
However, no one will design your diet based on a genetic test. First, the gut microbiota plays a large role in digestion and the ability to absorb certain nutrients. Second, there are many general dietary recommendations that are appropriate for everyone, regardless of genetic characteristics. For example, maximize the intake of raw vegetables and greens, avoid fast carbohydrates and trans fats.
The value of these "general" recommendations far outweighs the benefit that can be derived from a genetic test. Therefore, just for the sake of an "individualized diet" it is not worth spending money on a test.