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Chromosomal pathology of the fetus: what it is, markers, transcript

During pregnancy, fetal chromosomal abnormalities, which are inherently hereditary diseases, can be diagnosed during various tests and studies. They are due to changes in the structure or number of chromosomes, which explains their name.

The main cause is mutations in the genital cells of the mother or father. Of these, only 3-5% are inherited. Due to such deviations, about 50% of abortions and 7% of stillbirths occur. Since these are serious gene defects, throughout pregnancy, parents should be more attentive to all prescribed tests, especially if they are at risk.

The essence of the disease

Chromosomal pathology of the fetus: what it is, markers, transcript

If parents (both of them) have hereditary diseases in the family, they first need to know what it is – fetal chromosomal pathologies that can be detected in their child while he is still in the womb. Awareness will allow you to avoid unwanted conception, and if this has already happened, to exclude the most serious consequences, ranging from fetal death of the baby and ending with external mutations and deformities after his birth.

In a normal, healthy person, the chromosomes line up in 23 pairs, and each is responsible for a particular gene. A total of 46 is obtained. If their number or structure is different, they speak of chromosomal pathologies, of which there are many variations in genetics. And each of them entails dangerous consequences for the life and health of the baby. The main reasons for this kind of anomaly are unknown, but there are certain risk groups.

With the world on a thread. One of the rarest chromosomal abnormalities is called feline cry syndrome. The reason is a mutation of the 5th chromosome. The disease manifests itself in the form of mental retardation and the characteristic cry of a child, which is very similar to a cat’s cry.

Chromosomal pathology of the fetus: what it is, markers, transcript

In order to prevent or recognize chromosomal abnormalities of the fetus during pregnancy, doctors should ask future parents about the hereditary diseases and the living conditions of their families. According to recent studies, this is what gene mutations depend on.

There is a certain risk group, which includes:

  • parents (both) are over 35 years old;
  • the presence of HA (chromosomal abnormalities) in blood relatives;
  • harmful working conditions;
  • long stay in ecologically unfavorable area.

In all these cases, there is a fairly high risk of chromosomal pathology of the fetus, especially in the presence of hereditary diseases at the gene level. If these data are detected in a timely manner, doctors are unlikely to advise the couple to give birth at all. If the conception has already taken place, the degree of the child’s injury, its chances of survival and further full life will be determined.

The mechanism of occurrence. Chromosomal pathologies develop in the fetus when a zygote is formed and a sperm and egg cell merge. This process is not controllable, because it is still little studied.

Chromosomal pathology of the fetus: what it is, markers, transcript

Since the process of the emergence and development of such deviations is not well understood, markers of chromosomal pathology of the fetus are considered conditional. These include:

  • the threat of miscarriage, pain in the lower abdomen in early pregnancy;
  • low levels of PAPP-A (protein A from plasma) and AFP (protein produced by the body of the embryo), elevated hCG (human chorionic gonadotropin – placenta hormone): to obtain such data, blood is taken from the vein for 12 weeks (+ / – 1-2 weeks);
  • the length of the nasal bones;
  • enlarged cervical fold;
  • fetal inactivity;
  • enlarged renal pelvis;
  • slow growth of tubular bones;
  • previous aging or hypoplasia of the placenta;
  • fetal hypoxia;
  • poor results dopplerometry (ultrasound method to detect circulatory pathologies) and CTG (cardiotocography);
  • little and plenty of water;
  • hyperechoic intestine;
  • small size of the maxillary bone;
  • enlarged bladder;
  • cysts in the brain;
  • swelling in the back and neck;
  • hydronephrosis;
  • facial deformities;
  • umbilical cord cysts.

The ambiguity of these signs is that each of them individually, like the entire complex listed above, can be the norm, due to the individual characteristics of the mother or child. The most accurate and reliable data usually give a blood test for chromosomal pathology, ultrasound and invasive techniques.

Through the pages of history. Researching the chromosomes of modern humans, scientists found that they all received their DNA from one woman who lived somewhere in Africa 200,000 years ago.

Diagnostic methods

Chromosomal pathology of the fetus: what it is, markers, transcript

The most informative method for diagnosing fetal chromosomal abnormalities is the first screening (it is also called a double test). Make in 12 weeks of pregnancy. It includes:

  • Ultrasound (identified markers indicated above);
  • blood test (taken from a vein on an empty stomach), showing the level of AFP, hCG, APP-A.

It should be understood that this analysis of fetal chromosomal abnormalities cannot provide an accurate, 100% confirmation or refutation of the presence of anomalies. The task of the doctor at this stage is to calculate the risks that depend on the results of the research, the age and history of the young mother. The second screening (triple test) is even less informative. The most accurate diagnosis is invasive methods:

  • chorionic biopsy;
  • cord blood sampling;
  • analysis of amniotic fluid.

The goal of all these studies is to determine the karyotype (a set of features of a set of chromosomes) and, therefore, chromosomal pathology. In this case, the accuracy of diagnosis is up to 98%, while the risk of miscarriage is no more than 2%. How does the decoding of the data obtained in the course of these diagnostic methods?

Ultrasound and risks to the fetus. Contrary to the common myth about the dangers of ultrasound for the fetus, modern equipment allows to reduce the negative impact of ultrasound waves on the baby to zero. So do not be afraid of this diagnosis.

Decoding and calculation of risks

Chromosomal pathology of the fetus: what it is, markers, transcript

After the first double screening is done, ultrasound markers of the chromosomal pathology of the fetus, which were identified during the study, are analyzed. Based on them, it calculates the risk of developing genetic abnormalities. The first sign is the abnormal size of the collar space in an unborn child.

Ultrasound markers

Chromosomal pathology of the fetus: what it is, markers, transcript

Chromosomal pathology of the fetus: what it is, markers, transcript

Chromosomal pathology of the fetus: what it is, markers, transcript

Absolutely all ultrasound markers of chromosomal pathology of the fetus during the first trimester are taken into account in order to make the necessary calculations of possible risks. After this, the clinical picture is supplemented with a blood test.

Blood markers

Chromosomal pathology of the fetus: what it is, markers, transcript

All other indicators are considered deviations from the norm.

In the II trimester, inhibin A, unconjugated estriol and placental lactogen are still being evaluated. The entire transcript of the results of the research carried out is made by a special computer program. Parents can see the following values ​​as a result:

  • 1 to 100 – means that the risk of genetic defects in a baby is very high;
  • 1 in 1000 is the threshold risk of chromosomal pathology of the fetus, which is considered normal, but a slightly underestimated value may indicate the presence of some anomalies;
  • 1 to 100,000 is a low risk of chromosomal abnormality of the fetus, so it’s not worth fearing about the health of the baby from the genetic point of view.

After the doctors calculate the risk of chromosomal abnormality in the fetus, additional research is ordered (if the value obtained is lower than 1 in 400), or the woman calmly proceeds with the pregnancy until a satisfactory outcome.

This is curious! The male Y chromosome is the smallest of all. But it is she who is transmitted from father to son, maintaining the continuity of generations.

Chromosomal pathology of the fetus: what it is, markers, transcript

Parents whose child had chromosomal abnormalities prenatally discovered should understand and accept for granted that they are not treated. All that medicine can offer them in this case is an artificial interruption of pregnancy. Before making such a responsible decision, you need to consult the doctors on the following issues:

  • What pathology was diagnosed?
  • What consequences will it have for the life and health of the child?
  • Is the threat of miscarriage and stillbirth great?
  • How old do children live with such a diagnosis?
  • Are you ready to become parents of a disabled child?

To make the right decision about whether to leave a sick baby or not, you need to objectively evaluate all the possible consequences and results of chromosomal pathology of the fetus, together with your doctor. In many ways, they depend on what kind of genetic abnormality physicians suggest. After all, a lot of them.

Curious fact. Patients with Down syndrome is called the solar people. They are rarely aggressive, most often very friendly, sociable, smiling and even talented in some ways.


Chromosomal pathology of the fetus: what it is, markers, transcript

The consequences of chromosomal abnormalities identified in the fetus, can be very different: from external malformations to the central nervous system. In many ways, they depend on what kind of anomaly occurred with the chromosomes: their number has changed or mutations have affected their structure. Among the most common diseases are the following.

Chromosome abnormality

  • Down syndrome is a pathology of the 21st pair of chromosomes, in which there are three chromosomes instead of two; accordingly, these people have 47 instead of the normal 46; typical symptoms: dementia, delayed physical development, flat face, short limbs, open mouth, squint, protruding eyes;
  • Patau syndrome – disorders in the 13th chromosome, a very severe pathology, as a result of which newborns are diagnosed with many malformations, including idiocy, multiple eyes, deafness, mutations of the genital organs; such children rarely live to see a year;
  • Edwards syndrome – problems with the 18th chromosome, often associated with the elderly age of the mother; children are born with a small lower jaw and mouth, narrow and short eye slits, deformed ears; 60% of sick babies die before 3 months, and 10% live to a year, the main causes of death are respiratory failure and heart defects.

Violation of the number of sex chromosomes

  • Shereshevsky-Turner syndrome is an abnormal formation of the sex glands (most often in girls), due to the absence or defects of the sex X chromosome; symptoms include sexual infantilism, skin folds in the neck, elbow joints deformity; children with such chromosomal pathology survive, although childbirth is very difficult, and in the future, with the right maintenance treatment, women can even carry their own baby (through IVF);
  • polysomy on the X or Y chromosome is a variety of chromosome abnormalities, characterized by a decrease in intelligence, an increased likelihood of developing schizophrenia and psychosis;
  • Klinefelter syndrome – X-chromosome disorders in boys, which in most cases survive after childbirth, but have a specific appearance: lack of vegetation on the body, infertility, sexual infantilism, mental retardation (not always).


  • such a chromosomal pathology in a fetus is always fatal before birth.

Why there are gene mutations at the chromosome level, scientists are still trying to figure out. However, this is still only a matter of the future, and at this point in time, chromosomal pathologies detected in utero in the fetus account for up to 5% of all cases.

There are a number of conclusions about the dangers of detergent cosmetics. Unfortunately, not all newly-made moms listen to them. In 97% of baby shampoos, the dangerous substance Sodium Lauryl Sulfate (SLS) or its analogues is used. Many articles have been written about the effects of this chemistry on the health of both children and adults. At the request of our readers, we tested the most popular brands. The results were disappointing – the most publicized companies showed the presence of those most dangerous components. In order not to violate the legal rights of manufacturers, we cannot name specific brands.

The company Mulsan Cosmetic, the only one who passed all the tests, successfully received 10 points out of 10 (see). Each product is made from natural ingredients, completely safe and hypoallergenic.

If you doubt the naturalness of your cosmetics, check the expiration date, it should not exceed 10 months. Come carefully to the choice of cosmetics, it is important for you and your child.

What should parents do when they hear a similar diagnosis? Do not panic, accept, listen to doctors and together with them make the right decision – to leave a sick baby or agree to an artificial interruption of pregnancy.

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