Monosomy is what?

Genetic structure of a person is determined by 23pairs of chromosomes, which differ in shape and size. The largest chromosome 1. It is over the size of the chromosome 22 almost 4 times. 23 pair are the chromosomes X and Y. They determine the sex of people. In women 23, the pair contains 2 chromosomes X, this pair is designated XX. In men, 23 pairs consist of their chromosomes X and Y, i.e. is a pair of XY.

When an embryo is formed in the uterus of the future mother,He does not yet have any signs of a person, but 23 pairs of chromosomes already determine the sex of the future baby. The previous 22 pairs are called autosomes. They ensure the development of all internal organs and tissues of the baby.

Infertility as one of the signs of monosomy

Female infertility can be the resultvarious pathologies. In the case of a disruption in the structure of the 23 pairs of chromosomes, it is laid even before birth, when the potential mother herself was in a state of embryo in the womb of the mother.

If the pair XX is missing one chromosome X orit is damaged, such a pathology is called monosomy X. Infertility is one of the most revealing signs of X monosomy. Modern medicine studies both the signs of this pathology, and the ways of its treatment.

What it is?

Monosomy is a deviation called by namewho discovered him as a scientist of Turner's syndrome. This genetic disease happens only in girls. According to statistics, it is found in about 1 out of 2500 cases.

At this point in the development of medicine, preventTurner syndrome is impossible. Girls with this pathology can lead a normal life, but they need a doctor's observation, as complications can develop.

Other signs of monosomy

It was revealed that girls with the probability of having a syndrome of monosomy even in childhood may have the following signs of the disease:

In infancy, the hands and feet are swollen.
Males are lagging behind their peers in growth.
The palate of these girls is higher than that of the average child, and the ears are lower.
Sick girls are prone to gaining excessive weight.
Flat feet are often observed.
Eyelids hang low over the eyes.
Strabismus.
The neck is shortened.
Observation of hairy body parts.
Shortened hands.

In addition to these diseases, a teenage girl can be identified:

Heart disease (dislocation of valve walls).
The slowing of the onset of puberty.
Hearing problems.
Frequent elevation of blood pressure (hypertension).
Constant diseases associated with infections in the ears.
Dryness in the eyes.
Violation of posture, up to scoliosis.

From the point of view of sexual development, one observes:

Disproportion of the external genitalia.
Underdevelopment of mammary glands.
Absence of hair under armpits and above the pubis.
Underdevelopment of the uterus.
Absence or passivity of the ovaries.
Low content of female hormones.
Menstrual passivity, up to the absence of menstruation.

Difficulty diagnosing symptomsis that the same signs can be observed in other diseases. If they are in a girl of any age, it is necessary to have a check-up at a polyclinic.

One of the characteristic features of monosomy on sex chromosomes is the excess of the skin on the sides of the neck, which forms longitudinal folds.

The causes of the appearance of monosomy

At this stage of the development of science in detailsTo establish the reasons of occurrence at a fruit of a monosomy it was not possible. What is known for sure - pathology is not connected with heredity. The main influence on the appearance of pathology in the fetus is the gene disorders of the germ cells of the father during the period of conception. This is the main reason for monosomy.

If the genes of the father have undergone a mutation, arearrangement of the structure of the X chromosome, in a child - a girl, too, 23 pairs of chromosomes can be damaged. But it should be noted that in such a family it is not worthwhile to put a cross on the birth of children. At the father with infringement of an X-chromosome it is very probable conception and a birth of quite healthy child.

Why does the X chromosome appear? The causes of this disease are being studied, but at this stage medicine can say:

The appearance of monosomy in the fetus is not associated with unfavorable external conditions.
This pathology is not inherited. Otherwise, it would receive all the girls in the family of a genetically injured father.
The most likely cause of Turner's syndrome is the influence of harmful factors on the sex cells of the father shortly before conception.
During the period of division of the zygote and its transformation into an embryo, failures can occur, which are the cause of the mosaic type of monosomy.

Diagnosis of the disease

To the monosomy of the chromosome in the fetus was excluded,even before the birth of a woman at risk, they make a special genetic examination. This examination - prenatal genetic analysis - includes ultrasound examination, biopsy of the muscles and fetal skin, a laboratory blood test.

Such serious examinations the doctor appoints,when it comes to whether to leave the fetus or terminate the pregnancy. Therefore, they are appointed in the first 3 months of pregnancy. That is, if the family does not decide the question whether or not to be a child, surveys are not appointed.

A physician can recommend a genetic examination so that 21 chromosome monosomy is excluded if:

The future mother is over 35 years old.
In the family of a pregnant woman, hereditary pathologies were observed.
In the family, fragile (fragile) X chromosomes were observed.
Suspicion of hemoglobinopathy.
Suspicion of Down's syndrome in the child and other related to heredity, adverse situations.

When diagnosing such moments are taken into account thatThe examination should not cause harm to the health of the mother or the child, it can not lead to loss of the fetus. Doctors conducting diagnostics are required to have high qualifications for diagnosis based on the results of the survey.

Before conducting a genetic examination, a womanshould undergo a screening test at a gynecologist in his clinic, so that the doctor decides whether the pregnant woman is at risk, ie, is there a chance that the fetus will have a syndrome of monosomy. Only after a positive answer to this question the pregnant woman is sent for a genetic examination.

In prenatal diagnosis, there are othermethods - a puncture of a fetal bladder for the purpose of taking amniotic fluid for analysis, taking blood from the umbilical cord, fetoscopy. The latter is the introduction of the probe and the examination of the fetus through it. Fetoscopy is used very rarely, because at the modern level of medical equipment development this procedure is successfully replaced by ultrasound.

If the fetus did not detect monosomy on the X chromosome in time, and a suspicion of a diagnosis appeared several years after birth, the girl is examined in the following ways:

The absence of sexual chromatin is determined.
The karyotype is determined.
Consultation of a children's gynecologist is under way.
They make ultrasound of internal genital organs.
At the age of 9-10 years, a blood test for hormones is performed.
An x-ray of brushes is assigned to the correspondence of bone development to the age norm.

According to the results of the survey, a special commission may decide on disability.

Types of monosomy

Monosomy is a disease that happens to be differenttypes. In a girl born, a second chromosome in pair XX may be absent altogether. This type of genetics is designated as 45X0. These girls are completely absent or undeveloped ovaries and uterus. Their sexual maturation will not take place. There is no chromosome, which determines the development of secondary sexual characteristics, the sex organs themselves and the corresponding hormones.

If the second chromosome in pair XX is present,genetic type 46 XY. In this case, the girl will have a uterus and ovaries, but they will have a rudimentary structure, i.e., she will not be able to ovulate and conceive a child.

A much more dangerous case is when onechromosomes are not enough in pairs 1 to 22. They are called autosomes. With the normal development of the zygote in each cell, the two chromosomes are sent to its different poles. If one autosome is not enough, only the existing chromosome is sent to the cell pole. When it merges with a healthy one, the zygote is obtained with an abnormal amount of chromosomes. This leads to the death of the fetus and the spontaneous termination of pregnancy. If the number of chromosomes is greater by 1 than in the standard version, a miscarriage may not occur, but then a child is born who is unable to live long.

Partial monosomy

Partial monosomy is formed upon breakagechromosome, as a result of which one pair and one part of the second chromosome remain in the pair. The cause of the pathology is the structural chromosome rearrangement of the parental cells of the parents in the period shortly before conception. The consequences of the disease depend on which particular chromosome underwent partial destruction.

Syndrome "cat's scream"

The destruction of a part of the chromosome in 5 pairs creates the syndrome of "cat screaming". The larynx of a sick child is narrowed, the cartilages are soft, as a result, the baby's crying resembles a cat's meow.

This type is also characterized by muscle lethargybaby, moonlike face, mental underdevelopment and physical lag in comparison with their peers. The child has underdevelopment of the skull, low ears, strabismus and vision problems. As a rule, such children suffer from heart defects. These patients do not last long - the term reaches no more than 10 years. A similar pathology is seen in 1 of 45 000 cases.

Wolff-Hirschhorn Syndrome

Rupture of one chromosome from 4 pairs (syndromeWolf-Hirschhorn) occurs in 1 case out of 100 000. Children who have monosomal chromosomes of 4 pairs, are more likely to be obtained from young mothers and fathers. The weight of the child at birth is significantly less than the norm - about 2 kg. Infants are delayed physical and mental development, motor skills are complicated very slowly. They suffer from the development of the skull.

On external grounds, it may be noted that the beak-shapednose, protruding forehead, low ears, longitudinal folds in front of the ears. They also have muscular lethargy. They almost do not react to external stimuli. Such children are prone to convulsions. Outwardly they may have an abnormal eye structure, a small mouth with lowered lips in the corners, a curvature of the feet. Sick children often suffer from heart defects. Affected kidney diseases. Most of the children with this chromosomal destruction do not survive to a year.

Orbeli Syndrome

Rupture of a chromosome of 13 pairs is called a syndromeOrbeli. Children with this deviation are born with a low weight - up to 2.2 kg. Have pathologies of almost all internal organs. They have an underdeveloped skull, there is no nose bridge - the forehead immediately passes into the nose. The nose has an enlarged width, the sky is high, the ears are understated. The baby has visual abnormalities, underdevelopment of the musculoskeletal system. There may be no natural rectal canal and anus. Often observed heart disease, kidney disease, brain pathology. These children are usually oligophrenic, they are seized by convulsions, they often lose consciousness. Infants do not live up to 1 year.

Monosomy is a very dangerous disease, while children with partial monosomy are extremely rare. Future moms do not need to tune in to such a sad event.

Complications of monosomy X

Women with monosomy X are susceptible to various diseases of the internal organs more often than genetically healthy people. They should be observed at the doctor and periodically undergo medical examination.

A common complication is kidney pathology. In sick women, infectious diseases of the genito-urinary organs often appear, they are incorrectly located, and the kidneys are not fully developed.

If the monosomy of a person has a place to be, thensometimes the thyroid gland suffers, in which the insufficient level of hormones necessary for the body is produced. The thyroid gland inflames, because of what these troubles occur. Treatment can only serve as a medication that supports a normal hormonal background. They should be appointed by a doctor. Self-medication is unacceptable.

Those suffering from Turner's syndrome are prone to celiac disease. This pathology is expressed in the occurrence of allergies to gluten protein. Patients can not eat products from wheat and barley.

Complications can give any monosomy. Diseases that accompany monosomy may be different, for example, cardiovascular diseases. Women with pathology should observe a cardiologist who will monitor the condition of their aorta and will not allow the development of hypertension.

As patients with Turner's syndrome are prone to obesity, they may face diabetes.

Frozen pregnancy

Genetic pathologies, including monosomyfetus, is considered one of the reasons for the development of a frozen pregnancy. This is the death of the fetus inside the womb of the mother. With monosomy, this happens before the 12th week of pregnancy. Sometimes the life of the fetus is longer - up to 20 weeks. Such a danger threatens if the fetus lacks one of the chromosomes from pairs 1-22, this is the so-called trisomy. Monosomy is the reason for a deliberate termination of pregnancy.

Trying to save the fetus with serious anomaliesdevelopment does not seem to be meaningful. Frozen pregnancy results in miscarriage. This risk affects women over the age of 35 - 40 years, as well as those who have had it before.

Scientists also noted a decrease in the life span of women with monosomy, a tendency to atherosclerosis, tumors.

Treatment of monosomy

Monosomy is a pathology that does not treatgives in, but doctors successfully cope with its consequences. The essence of the treatment is that the organism devoid of hormonal regulation by the ovaries needs artificial regulation. The pathology of internal organs is treated medically or surgically. Complex treatment includes:

Admission of drugs of growth hormones to girls immediately after diagnosis.
By the age of sexual maturation of healthy children suffering from monosomy, sexual hormones are prescribed.
Wishing to endure a child with women with pathology helps reproductive medicine - the introduction of a donor fertilized egg with further monitoring of the course of pregnancy.
Treatment of pathologies of internal organs with modern preparations and procedures.
Psychological assistance to women in order to adapt them in the social environment, taking into account the characteristics of the physiology.

The most important point in treatment isits timely start is immediately after the diagnosis. The second point is the consideration of the type of monosomy. If her type is 45X0, then the woman will not be able to have her child in any ways. Psychological assistance should prepare her for the thought of adopting an orphaned child.

Mosaic view of monosomy X - 46XY with modernThe development of medicine makes it possible to carry out your child. But he can be born sick. Adoption is more preferable in this variant.