Developmental deviations and difficulties conceiving a child are often associated with inherited disorders. If one of the parents has relatives suffering from genetic diseases, or he himself is a carrier, it is advisable to undergo examination before planning the birth of a baby. Doctors take a karyotype test if they suspect pathologies of chromosomes or DNA molecules. To conduct the study, blood is taken from the patient and treated with a staining compound. After processing, the size, shape and number of chromosomes are examined under a microscope.
Definition
A karyotype is an individual set of chromosomes that has its own characteristics for each individual biological species and an individual. A person has only 23 pairs of chromosomes, that is, a total of 46. Of the twenty-three pairs, only one determines sex, and the rest have no differences in structure. Genetic karyotype analysis allows you to identify deviations in the composition or structure of chromosomes. Thanks to this study Doctors can take timely measures to prevent the pathology from causing serious complications, including the death of the fetus.
Important! It is enough for future parents to undergo karyotyping once in their life to ensure the absence or presence of pathologies.
When to take a test
The analysis is relevant for people of any age, because not everyone has been examined by a geneticist since early childhood. There are no contraindications for pregnant and nursing mothers. But first of all, research is required for newborns who early diagnosis will help identify dangerous genetic diseases that affect life expectancy. In-hospital analysis for the karyotype of spouses is often carried out as prescribed by a doctor, but not everyone knows what kind of examination this is. For couples wishing to have a child, examination is indicated in the following cases:
- After repeated unsuccessful attempts to conceive.
- Menstrual irregularities.
- If there have been previous miscarriages or stillbirths.
- In previously born children, delays in mental or physical development were recorded.
- Already at the stage of pregnancy, developmental disorders were detected in the fetus.
- If the future mother and father are close relatives.
- In the presence of bad habits from one of the parents.
- Living in a region with an unfavorable environmental situation or working in a hazardous industry.
- Planning your first pregnancy after 35 years - the reason lies in the fact that chromosomes can change with age.
- If parents have genetic diseases, even if healthy children were born before.
Attention! Modern doctors It is recommended that all couples be tested, since not every carrier exhibits pathologies, and therefore many are unaware of them.
Problems, including infertility, are identified when a person decides to have a child.
How the research is carried out
The analysis is taken during the metaphase period, which lasts from two to ten minutes. It is at this moment that it is easiest to examine the chromosomes through a microscope. There are three ways to detect abnormalities - molecular, cytogenetic and molecular targeted. It is up to the doctor to select one method or another. Before the karyotype analysis is carried out, you need to prepare:
- cure colds If a person is sick, then the test can be taken no earlier than two weeks after recovery.
- 30 days before visiting the hospital, stop taking antibiotics or reduce their consumption according to the doctor’s instructions.
- Do not drink alcohol for three days before testing.
- On the day of the test, you should have a hearty breakfast.
Venous blood is taken for testing. The material obtained from the patient is treated with a dye to identify chromosomes. Next, the doctor takes several pictures, which make it possible to determine the number of DNA molecules and pathological changes.
Important. The molecular method is necessary to detect small areas of structural abnormalities of chromosomes less than 5 million nucleotides in size.
For more detailed diagnostics, an advanced or targeted molecular method is used.
How to decrypt
For representatives of the stronger sex, the normal karyotype analysis results are 46, XY, and for women - 46, XX. The number 46 indicates the normal number of chromosomes, and the X and Y at the end indicate the shape, structure and size of the chromosome. healthy person– for men and women these indicators differ. Based on the test results, the doctor will make several notes on the form. Understand medical terms deciphering them will help:
- Translocation - a chromosome rearrangement has occurred. If the patient has a balanced translocation, then it most likely will not manifest itself. If unbalanced, serious deviations are possible.
- Mosaicism - cells with genetic characteristics different from normal are found.
- Trisomy – this pathology occurs most often, the patient has an extra chromosome. The most common occurrence is the appearance of a copy of chromosome 21, leading to diseases such as Down syndrome.
- Inversion - a section of a chromosome is rotated 180 degrees.
- Monosomy is only one of the pairs of homologous chromosomes in a genotype.
- Deletion – a fragment of a chromosome is lost.
What to do if deviations are found
You should not assume that anomalies in carinotype analysis always indicate that a married couple will have a sick child, or that they will be childless altogether. For example, parents with a balanced translocation may be born healthy baby, who will not have chromosomal pathologies. Even though the prices for karyotype analysis are high and start at three thousand rubles, it is not advisable to refuse it. Perhaps, based on the results, the doctor will advise you to undergo treatment and only then plan a pregnancy.
Attention! If a woman knows that she will have a child with pathologies, she needs to pay attention healthy image life and follow the doctor’s recommendations.
Genetic abnormalities can occur in different ways. With trisomy of the thirteenth and eighteenth chromosomes, children die in the first year of life. People with Down syndrome are delayed in mental development, but the mortality rate is much lower than with similar diseases. Abnormalities of sex chromosomes, such as Shereshevsky-Turner syndrome, often lead to infertility, but a person with these disorders can live to old age. And with monosomy X, about 5% of women have the opportunity to give birth to a baby. It is important to consult a geneticist who will accurately diagnose. A genetic disease cannot be completely cured, but if you undergo regular treatment, your quality of life will improve.
Perhaps the happiest event for every married couple is the birth of a child. But, unfortunately, at present many are faced with the problem of the impossibility of conceiving. The main reason is the infertility of one of the spouses as a result of possible genetic disorders. This occurs due to a change in structure when the number of chromosomes is disrupted, or under the influence of unfavorable conditions environment when others happen genetic mutations. To identify all these deviations and avoid problems in the future, it is important not only to test the couple for genetic compatibility, but also to undergo a molecular genetic examination.
The importance of determining the karyotype of spouses
One of the most important genetic studies in preparation for conception is the analysis of the karyotype of the spouses. A karyotype is a description of all the characteristics of the chromosomes that carry DNA. This analysis allows you to determine or predict the possibility of their occurrence in offspring. If one of the parents has an unfavorable set of chromosomes, there is a risk that the child may be born with a severe form of mental retardation or other diseases. It is impossible to change a person’s karyotype, but if the deviation is determined in a timely manner, methods for identifying the karyotype in the fetus and the possibility of treating it are used.
There is also a high probability of pregnancy failure due to chromosomal abnormalities. But thanks to timely identification of the problem and initial pregnancy planning, there is a possibility of the birth of healthy offspring. In cases where it is not possible to treat one of the spouses, special donor programs have been created to help couples in having a child.
After the karyotype of the spouses is determined, a diagnosis of chromosomal syndromes is carried out - such a diagnosis allows one to determine abnormalities in the development of the fetus due to structural rearrangements in the chromosome set of one of the parents. In most developed countries, such analysis is mandatory before marriage. It is especially important to carry out this analysis in families who cannot conceive a child for a long time, or in cases where there have already been miscarriages (abortion). Determining the woman’s karyotype in this case is the most important task. That is why such tests are necessary and help avoid the birth of children with severe pathology.
Karyotype analysis
The procedure to determine the karyotype of spouses is completely painless and consists of submitting results. The results are determined within two weeks and make it possible to identify deviations in the structure of chromosomes and their number. With good results total A healthy person has 46 chromosomes, two of which are sex chromosomes and are defined as XY in men and XX in women. In rare cases, chromosomal or caused pathological abnormalities, lead to the impossibility of bearing a child and, as a consequence, to miscarriage or infertility.
From the blood taken to determine the karyotype of the spouses, mononuclear leukocytes are sifted out and added active cells, capable of sharing. At a certain point, the division process is stopped, the resulting cells are stained, enlarged and photographed using a microscope. Staining is done using various dyes (classical and spectral tests), which allows you to get a visual representation of the full set of chromosomes.
To obtain the best results in the diagnosis and treatment of infertility and other diseases, the best solution is to contact the center reproductive medicine. In such centers, spouses can receive the consultations they need from experienced specialists, who will subsequently help them choose the right courses of treatment. The cost of tests and treatment in such centers corresponds to the attention and convenience provided and is completely justified in achieving the goal - the birth of healthy offspring.
Among the causes of infertility, genetic and immunological factors occupy a special place. Special - because they cannot be corrected or are very difficult to correct. These same circumstances influence not only the possibility of conception, but also the course of pregnancy and the health of the unborn child, often becoming the causes of miscarriages or congenital diseases. Therefore, analysis of the karyotype of a married couple and HLA karyotyping are studies necessary to identify the causes of infertility and minimize the risks of genetic abnormalities.
Why take karyotype and HLA tests?
Karyotype and HLA typing tests help determine the genetic and immunological causes of infertility A karyotype refers to the characteristics of chromosomes inherent in an individual organism - their shape, number, structure, and others. In some cases, altered chromosomes, without manifesting themselves or affecting the carrier, become the cause of infertility, the appearance of genetic diseases in a child, or a missed pregnancy. Karyotyping is a blood test procedure that is designed to identify chromosomal rearrangements in both parents, as well as changes in the location of their fragments. The analysis can be performed without aberrations or with aberrations. In the second case, this is an extended study that allows one to calculate the number of anomalies and identify their impact on the genome.
The second study is called HLA typing; it involves determining the spouses' histocompatibility antigens (Human Leucocyte Antigens), the set of which is also individual for each person. Thanks to their molecules, the body distinguishes foreign cells and produces specific antibodies against them. If the HLA of future parents is similar, we can talk about: the body perceives the embryo as a foreign body and rejects it.
Cost in clinics and laboratories in Moscow
The table shows approximate cost analyzes in several laboratories in Moscow.
| Karyotyping | HLA-typing | Notes | |
| Genomed, medical-geneticcenter | 5400 rub. (for each spouse) | 6000 rub. (for each spouse) | |
| Invitro | About 7000 rub. | 5100 rub. | Both analyzes are included in the program of a complete genetic examination of a couple, costing from 73 to 82 thousand rubles. for each of the spouses. |
| Bio-Optima | 5400 rub. | 5300 rub. | |
| C&R | From 5900 (without aberrations) to 9750 (with aberrations) rubles | 5550 rub. | When paying for tests online, the clinic provides a discount of up to 30%. |
| Institute of Genetics RAMS | 5000 rub. | 5000 rub. | |
| NTs im. Kulakova | 5000 rub. | 3500 rub. | |
| Medical Centerimmunocorrection | From 2900 to 5800 (with aberrations) | 2900 – one analysis, 5800 – pair typing |
Let us note some features of the tests in these clinics:
- The karyotype study is quite long - 21-23 days. HLA typing takes 5-7 days.
- Most clinics also offer comprehensive genetic tests aimed at diagnosing the likelihood of individual diseases in a child (for example, cystic fibrosis, autism and others).
- The price is indicated without the cost of blood sampling (200-300 rubles) and consultation with a geneticist (from 1500 rubles)
Only a doctor should interpret the research results! They are not a diagnosis or a basis for self-medication!
Indications for research
Both analyzes are optional. As a rule, they are prescribed in the following cases:
- Women planning pregnancy over 35 years of age.
- Spouses who have already had children with congenital diseases.
- Women with recurrent miscarriage.
- Families in which there have been repeated cases of early miscarriages.
- Couples suffering from infertility.
- In the event that an ultrasound revealed abnormalities in the development of the fetus.
- As part of the examination before
It happens, but miscarriages follow one after another. There is an analysis that allows you to clarify the causes of infertility and avoid the birth of a child with pathology. Elena Domracheva, Doctor of Medical Sciences, Professor, consultant of the cytogenetic service of the Hemotest Laboratory, tells the story.
Often the cause of infertility lies in a violation of the DNA structure or a change in the number of chromosomes. These genetic mutations can be congenital or occur during life due to adverse environmental influences.
To determine such deviations in the number of chromosomes and their structure, a special study is carried out - karyotyping. It is this that will allow us to determine the cause of infertility, identify severe inherited pathology and thereby prevent the birth of a sick child.
A karyotype is a combination of human chromosomes that determines all the unique characteristics of an organism. The norm is to have 23 pairs of chromosomes. Of these, 22 pairs of chromosomes are responsible for hereditary characteristics, such as body composition, human height, hair color, and so on. These chromosomes are the same in both men and women, which is why they are called autosomes. The gender of a person depends on the last 23rd pair. And it is precisely this that contains gender-related characteristics. Therefore, the karyotype formula for a man is 46XY, and for a woman - 46XX. A person's karyotype usually does not change with age.
Karyotyping reveals inherited diseases that are associated with deviations from the norm in the chromosome set (the number of chromosomes, which may be one more or less, their shape or defects in sections). Some pathologies in chromosomes can lead to miscarriages, others - to the birth of a child with developmental defects. Some abnormalities in the chromosome set may not manifest themselves in any way in a person in his or her Everyday life, but any deviation increases the risk of having a child with a pathology in the genes.
Why do karyotyping for spouses?
Karyotyping analysis is recommended for all married couples dreaming of offspring. This study becomes mandatory if the future father or mother has already been observed in the family genetic pathologies, as well as in preparation for IVF. Karyotyping is also necessary in case of unsuccessful pregnancies repeated several times in a row for no particular reason, or impaired sperm formation in men. Age over 35 years, even for one of the spouses, is also an indication for research.
Venous blood is used for the study, and the diagnosis itself does not require any special preparation. The only requirement is that 3-4 weeks before the test you should avoid taking antibiotics, and come to the laboratory after having eaten. It is also advisable to get enough sleep the night before and eliminate the impact of stressful situations on the body.
What does karyotyping allow you to determine?
The examination will help determine why a married couple cannot conceive a child, or why a woman is not able to bear a fetus, and will also identify the risk of developmental pathologies in the unborn baby. When examining amniotic fluid, karyotyping recognizes chromosomal diseases still in the womb (Patau, Klinefelter, Shereshevsky-Turner syndromes and others). They occupy one of the first places among hereditary pathologies and occur in newborns in 0.7-1% of cases.
Medical statistics indicate that chromosomal abnormalities in newborns are the cause of 45-50% of multiple birth defects development, about 35% of cases of mental retardation and 50% of absence of menstruation in women.
In adults, chromosomal abnormalities may not be clinically manifested at all or may occur in erased forms. Often a person considers himself healthy and is not aware of any genetic disorders. But he cannot have children. Therefore, a study of the karyotype of blood lymphocytes is mandatory for all infertile couples.
Where to get a karyotyping test
This is a difficult and time-consuming analysis. In ordinary district clinics It is unlikely that you will be able to donate blood for this study due to a lack of trained specialists and equipment. Karyotyping analysis can be done in some modern medical laboratories and clinics, family planning centers, genetic institutes, as well as mother and child centers.
In different clinics, the test preparation time varies from 14 to 28 days. It is worth adding that the karyotype does not change over time, and the procedure is performed only once in a lifetime.
The desire to have children with good health characteristic of any person, which is why many married couples go through various studies. One of them is karyotyping of spouses.
The study is also called the method of cytogenetic analysis. The essence of the event is to study the chromosome set of future parents. The test has an almost 100% result and helps determine the factors of a couple’s lack of conception.
In our country, the analysis is not widely known, while in Europe and the USA the procedure has been used for quite a long time. What is it and why is it done?
What is karyotyping and why is it performed?
The purpose of the study is to determine compatibility between partners, which allows you to conceive and give birth to genetically healthy offspring. Karyotyping is performed at the planning stage of the child. However, upon the onset of gestation, the procedure is also carried out: required material They also take it from the baby in the womb to determine the set of chromosomes.
It is easy for a geneticist to identify the risk of a hereditary abnormality in a baby. The body of a genetically healthy person contains 22 pairs of non-sex chromosomes and 2 pairs of sex chromosomes: XY in men, XX in women.
The study shows the presence of the following pathologies:
- Monosomy: absence of 1 chromosome in a pair (Shereshevsky-Turner syndrome).
- Trisomy: an extra chromosome in a pair (Down syndrome, Patau).
- Duplication: a specific part of a chromosome is doubled.
- Deletion: A fragment of a chromosome is missing.
- Inversion: The process by which a section of a chromosome turns around.
- Translocation: chromosomal castling.
Using karyotyping, the state of genes is assessed and the following is identified:
- Gene mutations responsible for the tendency to form blood clots. They can cause spontaneous abortion or infertility.
- Mutation of the Y chromosome - Klinefelter syndrome. A feature of the disease is the presence of the Y chromosome, despite the additional presence of the X chromosome, patients are always male. To achieve pregnancy, you will have to use donor sperm. Variants of the karyotype of Klinefelter syndrome: 47 XXY, 48 XXXY, 49 XXXXY.
- Gene mutations responsible for detoxification processes. There is a low ability of the body to disinfect surrounding toxic factors.
- Mutation in the cystic fibrosis gene. The probability is determined dangerous disease at the baby's.
Thanks to karyotyping, hereditary predisposition to a number of diseases is diagnosed - diabetes mellitus, myocardial infarction, hypertension and pathological processes in the joints.
How much does karyotyping cost? The price of the study depends on the city and the level of the clinic: the average cost is about 6700 rubles. However, all expectant parents are advised to take a test before conceiving. If abnormalities are detected in a married couple in a timely manner, a specialist can create optimal conditions for the development of the child and prevent miscarriage or premature birth.
ABOUT hereditary diseases the doctor says:
Indications for examination
When planning pregnancy, it is advisable for each family to conduct a cytogenetic study. Individual citizens are required to undergo molecular karyotyping.
Let's take a closer look at which category of persons is prescribed the procedure:
- One or both spouses are over 35 years old.
- Infertility of unknown etiology.
- Failure of IVF attempts.
- The presence of hereditary pathologies in the parents.
- Endocrine disorders in expectant mother.
- Impaired ejaculation or sperm activity of unknown etiology.
- The presence of unfavorable ecology and labor activity with chemicals.
- Having bad habits such as smoking, drinking alcohol, drugs or taking medications.
- Recorded cases of spontaneous miscarriages, missed abortions or premature births.
- Marriage with a blood relative.
- Already born children with genetic pathologies.
- One of the couple receives radiation exposure.
Preparing for analysis
To study chromosomes and determine gene deformation, it is necessary to take blood cells. Don't worry that laboratory test may harm you or your child: it is absolutely safe.
The method of preparing for the test includes measures that are carried out starting 2 weeks before the expected analysis:
- Stop drinking alcohol and smoking.
- Do not take during this period medications, especially antibiotics.
- Take the test in the absence of acute diseases or exacerbation of chronic ones.
Mechanism
For the test, venous blood is taken from both partners. The study lasts for 5 days. During the specified time, lymphocytes in the mitotic division phase are isolated from the plasma. Within 72 hours, an analysis of the proliferation of blood cells is carried out, which makes it possible to draw a conclusion about the presence of pathology and the risk of miscarriage. At the division stage, a specialist examines chromosomes by preparing microslides on glass.
The laboratory technician can perform the test with or without diphostaining of chromosomes. For better visualization, the specialist performs differential staining of the nucleoprotein structure, after which their individual striations become clearly visible. The number of chromosomes is counted, the striation of paired chromosomes is compared, and the structure of each is analyzed.
The unique technology allows you to get an accurate result by examining 15 lymphocytes. This means you do not need to donate blood again or biological fluids. One karyotyping analysis of a married couple makes it possible to plan a pregnancy and give birth to healthy children.
When conception has already occurred, experts recommend doing a test at early dates gestation to identify pathologies such as Down syndrome, Turner syndrome, Edwards syndrome, cat cry and other anomalies. Material is collected from the child in the womb and spouses.
There are invasive and non-invasive methods of prenatal karyotyping. The first is considered safer and involves the implementation ultrasound diagnostics with blood sampling from the expectant mother to determine markers.
The invasive method is considered more accurate and almost completely eliminates errors, but can sometimes be quite risky and therefore requires inpatient observation for several hours. To conduct such a study, special equipment is needed that is used to manipulate inside the uterus to take genetic material.
To identify traces of the influence of aggressive factors on a DNA strand, a karyotype with aberrations is determined. The procedure is considered an advanced genetic examination, in which specialists carefully examine 100 cells to calculate abnormal metaphases. The test is quite labor-intensive, and many laboratories do not conduct such a test.
What to do if the examination reveals abnormalities - the doctor advises
In people's cores somatic cells There are 46 chromosomes, one pair and they are sex chromosomes: the normal female karyotype is represented as 46 XX and the male karyotype - 46 XY. Having received the cariogram, the geneticist interprets the test and conducts a special consultation for the couple, during which he explains the possibility of having a child with pathology or abnormalities. He recommends that they undergo a course of therapy at the stage of planning a child, after which it is possible to prevent disorders in the baby.
When abnormalities are detected already during gestation, the doctor advises to terminate the pregnancy in order to try to conceive a healthy baby next time. Or the doctor gives the spouses the right to choose in which they will be ready for the birth of a “special” child. If everything is normal for the expectant parents and there is excellent compatibility, the specialist tells them in detail all the stages of pregnancy planning.
When identifying hereditary disorders You can use the donor's genetic material from your partner. For this purpose, the sperm of a healthy man is used.
Conclusion
Birth healthy child- the most important task parents. At the pregnancy planning stage, you can avoid pathologies by performing a cytogenetic study. Carrying out karyotyping of spouses allows us to identify the compatibility of the couple and possible violations in the baby, and during pregnancy, determine the presence of developmental abnormalities in the fetus.
