Trisomy X-syndrome. Causes, diagnosis, treatment

Trisomy on the X chromosome - a syndrome caused by genetics, caused by the presence of an additional X chromosome. Develops only in females. According to the researchers, it occurs with a frequency of 1 case per 1000 newborns, but often remains unrecognized due to the insignificant severity of symptoms. Scientists believe that 90% of women with trisomy live their lives without knowing about the existence of the mutation.

Types of pathology

The syndrome of trisomy on the X chromosome occurs in 2 variants: normal and mosaic. In the first case, an additional chromosome is present in all cells of the body. In the second, the genetic set of different cells is different. The classic clinical picture is described for patients with non-mosaic type of trisomy. Mosaicism affects the external signs of the disease and forms additional variants characterized by polymorphism of clinical manifestations:

46XX / 47XXX	Cells with 2 and 3 X chromosomes are identified. The negative influence of the additional chromosome is reduced, the signs of trisomy are less pronounced than in patients with the usual form.
45X / 47XXX	Cells with three and one additional chromosome are found. The manifestations of ordinary trisomy recede into the background, in women, a softened picture of Shereshevsky-Turner syndrome is found.
47XXX / 48XXXX	Tetrasomy causes almost the same changes as trisomy, but the signs of mutation are expressed more roughly and clearly. In patients with mosaicism, the symptoms of pathology are more noticeable than in ordinary trisomy.

Symptoms and Signs

The syndrome of trisomy on the X chromosome is characterized by significant variability. The severity of clinical manifestations ranges from almost imperceptible to obvious, attracting the attention of teachers and parents.

The most typical symptoms of the syndrome are:

• At certain age periods, there is some lag behind the age norm in speech, physical and psychological development.
• There are transient problems in communication with peers at school age, exposure to stress, and a high likelihood of abnormal behavior during puberty.
• There is a slight decrease in the level of intelligence in comparison with the average indicators (while the IQ is within the normal range), frequent learning problems, the need for additional pedagogical support.
• Characterized by rapid growth from 4 years to the beginning of adolescence - girls are taller than their peers, often have longer legs.

Infancy

Trisomy on the X chromosome does not cause external changes; babies with this syndrome look like normal healthy newborns. Sometimes attention is drawn to the low weight (the average weight of infants with this pathology is 3 kg), reduced head size and a slight decrease in muscle tone. The child seems lethargic, his arms and legs hang limply.

Younger age

Children lag slightly behind their peers in the development of motor and speech skills. On average, girls with trisomy begin to crawl at 10 months, and walk at 17 months. The delay is caused by decreased muscle tone and problems with coordination of movements. Possible unusual flexibility of the joints, increased fatigue during physical exertion. It is difficult for children to have complex motor acts, which can be expressed in the choice of simple games, difficulties in using cutlery.

Girls later begin to understand what was said, use syllabic speech, pronounce individual words and build sentences. They often need the help of a speech therapist. Some lag behind the average is also observed when mastering the toilet. The average potty training age is 3-4 years. At the same time, girls, no worse than healthy peers, master theoretical concepts: they learn to count on time, understand time, understand what money is.

Despite some difficulties in mastering movements and daily routines, with sufficient attention from parents and regular education, children do what their peers do: play the same games, successfully attend kindergarten. By the beginning of school age, the backlog in many parameters is leveled, the child goes to school on time.

School age

Half of the children learn subjects without any problems in accordance with their age. Some people need help from a reading or math tutor. Learning success correlates with the time of diagnosis: the earlier trisomy is detected, the fewer problems arise in school. Experts explain this by the possibility of successful correction of developmental lag in the early years.

Typical difficulties include poor handwriting and difficulty concentrating. Children have a slightly reduced vocabulary. They understand speech more literally, do not always read the hidden meanings. They tend to use short sentences and simple verbal constructions. This can lead to a decrease in academic performance in humanitarian subjects, anxiety if it is necessary to answer in the lesson.

At the same time, girls retain the ability to fully participate in the non-verbal component of communication. They understand facial expressions, intonations and bodily signals of the interlocutor no worse than their peers. Due to difficulties with concentration, they need to repeat the material many times. Often they realize that they are lagging behind their peers, which can lead to a decrease in self-esteem. It is difficult to make friends because they are prone to games that seem "too childish" to their peers.

Distinctive psychological characteristics are increased anxiety, low resistance to stress, frequent hyperactivity, a tendency to rituals and adherence to routines. During puberty, emotional outbursts and psychotomatic manifestations are possible. Outwardly, physical development is ahead of the norm, but the girls are thin, with long legs and thin bones. Children are more likely to have constipation, abdominal pain of unknown origin, scoliosis and disorders of the urinary system.

Puberty begins with some delay, then adolescents develop normally. Most women are fertile. Irregular periods are possible. Patients are often diagnosed with early ovarian wasting syndrome (OVF), which is presumably associated with the presence of an extra chromosome in half of the eggs that are not used by the body.

With successful correction of developmental lag, there are no intellectual and social problems in adulthood. Women successfully study in secondary and higher educational institutions, work, and form social ties. Some patients require correction of scoliosis, treatment of kidney disease. Due to the risk of developing ROS, it is necessary to pay sufficient attention to the health of the genitals and the functioning of the reproductive system.

Causes

The syndrome of trisomy on the X chromosome is provoked by violations at the stage of division of germ cells, the violation is formed even before fertilization. At the stage of meiosis, 2 X chromosomes do not diverge into different cells, but fall into 1 egg, which is then fertilized by a normal sperm that brings the 3rd X chromosome. Experts believe that the extra X chromosome is sometimes found in a malformed sperm and passed from the father, but such cases are extremely rare.

The reasons for the violation of the division of germ cells have not been established. Scientists have not found any connection between lifestyle, occupational hazards or negative environmental impacts. The only significant factor is the mother's age. Girls with trisomy are significantly more likely to be born to women over 33 years of age.

Diagnostics

The only way to reliably establish the presence of trisomy on the X chromosome is genetic analysis. Special studies to identify this pathology during pregnancy are not carried out, since most children are born practically healthy and develop without serious deviations from the norm.

Accidental detection of the third X chromosome is possible when screening a pregnant woman due to the high risk of other genetic diseases, primarily Down's syndrome. The cost of advanced analysis is 30-40 thousand. rub.

To collect material, it is necessary to carry out invasive interventions - amniocentesis or chorionic biopsy. These techniques increase the likelihood of miscarriage and the development of a number of disorders in the fetus, therefore, it is impractical to prescribe them separately to determine the extra X chromosome.

After birth, a genetic examination can be prescribed if you have an unusual appearance, deviations in mental and physical development. Trisomy is detected by karyotyping peripheral blood lymphocytes. The research cost ranges from 5-7 thousand. rub. It should be borne in mind that in girls with mosaicism, the result may be unreliable.

Prenatal diagnosis is prescribed at the place of management of the pregnant woman, the material is taken in the conditions of the gynecological department. To determine the karyotype of a girl or an adult woman, you can contact any specialized private clinic, for example, Invitro, Genomed or KDL.

Treatment methods

Trisomy on the X chromosome is a syndrome that in most cases does not require special treatment. Correctional techniques play the main role in ensuring normal development. Children with delayed speech development require the help of a speech therapist. When motor skills are lagging behind, classes are needed to improve fine motor skills and coordination of movements.

At school age, you should pay attention to academic performance. If necessary, you need to organize additional activities at home, planning them taking into account the child's increased distraction. If necessary, the participation of a tutor is possible. Socialization issues play an important role at school age. Since girls are prone to heightened emotionality and often suffer from communication problems with peers, they may need the help of a psychologist.

Early detection and prevention of scoliosis is required. In the absence of pathology of the musculoskeletal system, motor activity should not be limited. Despite the difficulties with the coordination of movements, with regular attendance of the sections, children successfully go in for sports. Before starting classes, it is necessary to assess the state of the musculoskeletal system.

SIA treatment

When ovarian depletion syndrome is detected, general therapeutic measures are taken to prevent the consequences of premature menopause. The best option is the early appointment of hormone replacement therapy before signs of menopause appear (in contraceptive mode).

General hormone therapy is complemented by local administration of estrogens in the form of vaginal suppositories. Patients are prescribed electrophoresis, hydrotherapy, acupuncture, vitamin therapy, sedatives. According to the indications, psychotherapy is performed.

Treatment of mosaicism with Turner syndrome

A special task is the treatment of patients with 45X / 47XXX mosaicism (a combination of X-chromosome trisomy and Shereshevsky-Turner syndrome). Unlike girls with non-mosaic trisomy, patients with Turner syndrome need complex measures to stimulate growth and the formation of secondary sexual characteristics. Hormone replacement therapy is required from the onset of puberty to natural menopause.

With adequate development, women can carry a child, but most require IVF using a donor egg. Patients may require surgical correction of vascular disorders and orthopedic pathologies. Excessive hair is eliminated by epilation.

Possible consequences and complications

The X-chromosome trisomy syndrome is characterized by a favorable course. Many girls, with sufficient parental attention, little or moderate participation by speech therapists, correctional teachers and tutors develop normally and do not experience difficulties in the subsequent life. An important factor influencing the prognosis is the early correction of problems with speech and motor activity that arise in the first years of life.

With a significant lag in psychological and speech development from the age norm and the absence of correction, children may not be sufficiently prepared for school, which entails a lag in most subjects, the need to transfer to special educational institutions, restrictions on choosing specialty.

The lack of correction of the delay in motor development does not lead to such severe consequences, but it can negatively affect the physical condition of patients and the attitude of peers, provoke the development of secondary neurotic disorders.

At the stage of schooling, it is important to give educational material taking into account the reduced ability to concentrate, the need for a greater number of repetitions. You should work on increasing your vocabulary, the ability to understand hidden meanings. Lack of attention from parents and teachers during this period, as in the previous case, can lead to decline in academic performance, although the consequences will not be as fatal as in the absence of compensation for early violations.

Girls with trisomy have certain personality traits that also need to be considered and compensated for. Difficulties in communicating with peers can lead to the perception of oneself as a "black sheep", the development of an inferiority complex, social fears that affect life in adulthood. The lack of sufficient emotional support sometimes becomes the cause of the development of depression and mental disorders of a neurotic level.

In childhood, you need to pay attention to the condition of the musculoskeletal system, treat and prevent postural disorders. The development of scoliosis can negatively affect the condition of the spine, heart and lungs. It is necessary to promptly identify and treat diseases of the urinary organs in order to prevent deterioration of kidney function.

Trisomy on the X chromosome can provoke certain disorders of the internal genital organs. The most important aspect of the syndrome is control over the state of the reproductive system in adult patients. Due to the high risk of developing SIA, women are not advised to postpone the birth of a child until a later age.

When symptoms of premature ovarian failure occur, hormone replacement therapy is required. In the absence of hormonal treatment, early menopause can lead to the development of osteoporosis, an increased risk of cardiovascular diseases, and a deterioration in the psychological state.

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