Modern knowledge from the field of genetics has already entered the phase of its practical application in applied medicine. Today, scientists have developed a set of genetic screenings, or tests that can identify genes that are the root cause of not only hereditary diseases, but also certain body conditions.
Trouble insurance
Child inherits from parents not only eye color and nose shape, but also he alth. In many countries, genetic analysis (screening, from English screening - “sifting”) is already included in the mandatory he alth insurance. In our country, this direction of early diagnosis of a child's he alth is only developing.
Each person carries up to ten defective genes in his genome, and in total we know more than 5 thousand diseases and pathological conditions associated with our gene set. This is statistics. Comprehensive medical genetic screenings can reveal up to274 gene pathologies. That is why anyone who cares about the he alth of their future children should consider undergoing a genetic examination.
Not just for risk groups
Genetic screening is often offered to pregnant women. But not only for them, the results of genetic analysis can be useful. Genetic screening allows you to determine a person's predisposition to a variety of diseases, provides information about the drugs that are most effective for a given patient. Studies provide information about a person's personality, tendency to be overweight, allow the development of special diets and lifestyle adjustments.
Examinations of pregnant women (perinatal screening before birth) are used to determine the pathology of the fetus as part of its general diagnosis. In our country, mandatory genetic screening of newborns is carried out, but we will talk about this separately. Genetic analyzes of prospective parents are used to determine the risk of having a child with congenital gene pathologies.
Not to mention genetic screenings to establish paternity and relationship, as well as the use of genetic data in the investigation of criminal offenses.
And yet there are risk groups
As it became clear, genetic analyzes can be carried out at the request of the patient and on the recommendation of a geneticist. Who is shown this analysis:
- Spouses who have hereditary diseases.
- Married couples whoare related to each other.
- Women with adverse pregnancy history.
- People who have been exposed to adverse and mutagenic factors.
- Women over 35 and men over 40. At this age, the risk of gene mutations increases.
Perinatal Screening
This is a generic term for a number of pregnancy screenings. It includes ultrasound, dopplerometry, biochemical analyzes and, in fact, screening for genetic diseases of the fetus, the purpose of which is to determine chromosomal abnormalities and malformations. Such studies include three main parameters in calculating risks to the fetus: the age of the mother, the size of the nuchal space of the embryo, and biochemical markers in the mother's blood serum that belong to the fetus or are produced by the placenta.
All tests for pregnant women are divided into:
- Genetic screening of the 1st trimester (up to 14 weeks of pregnancy). 80% of fetuses with Down syndrome are detected.
- 2nd trimester screening (from 14 to 18 weeks of pregnancy). Up to 90% of fetuses with Down syndrome and other pathologies are detected.
Previously, doctors recommended perinatal screening for women over 35 years old, since it is they who have an increased risk of developing Down syndrome in the fetus (chromosomal pathology in the form of 3 chromosomes 21 pairs) increases. Today, the doctor offers such an examination to all pregnant women at their discretion.
The first trimester is the most important
To everyone who doesn't remember -Recall that in the first two weeks of its life, the embryo goes through the main stages of embryonic development, when the neural tube and the rudiments of all organs and systems of the body are laid, it is implanted in the uterus.
That is why pregnant women who in the 1st trimester had acute respiratory viral diseases, herpes, hepatitis, were infected with HIV, had x-rays (even at the dentist) or x-rays, drank alcohol, smoked, took drugs or illegal drugs, sunbathed, pierced and even dyed their hair should consider consulting a geneticist.
What can be heard at the consultation
First of all, you need to prepare for it. Future parents should be aware of hereditary diseases from their relatives, take medical records and the results of all examinations. The geneticist will study all the submitted materials and, if necessary, send them for additional examinations (blood biochemistry, karyotype research).
It is important to remember that genetic screening is not 100% accurate. Sometimes, to clarify the pathology of the fetus, it is required to perform an amniocentesis (amniotic fluid sampling), a chorionic biopsy, and other rather complex tests.
What screening results look like
The correct result is expressed as the proportion of the chances of the fetus being affected by Down syndrome, neural tube malformation and other pathologies. For example, 1:200 means that the chance of a child having a pathology is one in 200cases. That is why 1:345 is better than 1:200. But that's not all. The doctor must necessarily compare the indicators of your result with the indicator of the age category of the area where the examination is taking place. The conclusion will talk about high, medium or low risk of developing a defect.
But that's not all. The analysis requires an individual approach, which takes into account ultrasound indications, family history, biochemical markers.
Neonatal Screening
This is the first genetic screening of a newborn. It was first introduced in 1962 for the early diagnosis of phenylketonuria in infants. Since then, endocrinological and metabolic disorders, blood pathologies and genetic abnormalities have been added to this disease.
The procedure for this screening is simple - the baby is taken from the heel immediately after birth and sent to the laboratory to check for diseases that are almost not diagnosed before the onset of symptoms, but when symptoms appear, lead to irreversible changes in the body. In case of a positive result, an additional examination will be required.
What can be revealed in an infant
This diagnostic is free and detects the following diseases:
- Phenylketonuria is a systemic disorder of protein metabolism, which in the later stages leads to mental retardation. The disease, detected in time and balanced by a special diet, does not develop.
- Hypothyroidism –decreased thyroid function. An insidious disease that leads to mental retardation and developmental delay.
- Cystic fibrosis is a severe disease associated with a gene mutation. In this case, the work of many organs is disrupted. There is no cure, but diet and special enzymatic preparations stabilize the patient's condition.
- Adrogenital syndrome - impaired function of the adrenal cortex, which leads to dwarfism.
- Galactosemia - deficiency of enzymes responsible for the metabolism of galactose.
However, five diseases are clearly not enough. For example, in Germany, newborn screening includes 14 diseases, and in the US - 60.
Genetic tests could save lives
Premarital screening of spouses to identify the carriage of mutant genes will enable doctors to more closely monitor the course of pregnancy, perinatal diagnostics will reveal pathologies, and all this will help ensure early correction of hereditary diseases in a child.
Natal diagnosis of newborns will reveal diseases that, with timely correction, will enable the child to develop normally. Early diagnosis of monogenic diseases (hemophilia or congenital deafness) will help to avoid many mistakes, sometimes fatal.
Genetic screenings in adults reveal multifactorial diseases - cancer, diabetes, Alzheimer's disease. Identification of a genetic predisposition to these pathologies determines a set of preventive measures aimed at reducing the risks of their development. Alreadytoday there are cases when the causes of blood cancer were identified at the genetic level, and the disease was transferred to the remission stage thanks to gene research.
And they can help improve it
The development of genetic Lifestyle tests is also a promising direction. They are designed to track the body's tendency to various environmental factors. They will show a predisposition to the absorption of various nutrients and their metabolic rate. And an experienced nutritionist will tell you how to eat and how to exercise based on your genetic characteristics.
