Triple X syndrome – is it hereditary, doctor’s appointment, tests, therapy

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Triple X syndrome, also known as trisomy X or 47, XXX, is a set of genetic defects caused by the presence of an extra, third, X chromosome in the cells of a newborn girl. In boys, this disease does not occur. Triple X syndrome occurs in 1 in 1000 live births to female babies.

Can a woman with syndrome X have children?

Many women with triple X syndrome have little or no symptoms. Girls with this genetic defect syndrome are usually taller than their peers. Sometimes symptoms such as:

– small head (microcephaly),

– eye wrinkle,

– weakened muscle tone (hypotonia).

Besides, there are no typical pathological physical changes. Rarely, there may be:

– premature decline in ovarian function – if the decline in ovarian function occurs before the expected menopause, ovulation is stopped; the woman cannot become pregnant then;

– kidney abnormalities: disorders of their structure or function; in some cases, only one kidney is present.

Sometimes a delay in the development of speech or motor skills (sitting, walking), developmental disorders in learning, e.g. dyslexia, as well as behavioral and emotional disorders, in extreme cases leading to difficulties in establishing social relations are observed. About 10% of girls experience epileptic seizures. Usually, sexual development is not impaired. If the ovaries fail prematurely, girls with triple X syndrome do not have problems getting pregnant.

Can the Triple X syndrome be inherited?

In humans, there are 46 chromosomes (23 pairs) in each cell. They contain genes, i.e. information carriers, that determine the entire body, from the growth to the shape of our nose. Two of them are the so-called the sex chromosomes, the X and Y, which determine the sex. In women, there are 2 X chromosomes (46, XX) in the cells and in men one X and one Y chromosome (46, XY).

In the triple X syndrome, the cells of the newborn girl’s body contain an extra copy of the X chromosome. As a result, the cells contain 47 instead of 46 chromosomes. The presence of additional genetic material contributes to the symptoms of the disease in some girls.

In most cases, triple X syndrome is not hereditary. It usually occurs as a result of a random abnormality in the formation of reproductive cells (egg, sperm). The effect of an error during cell division, called nondisjunction, is the presence of an abnormal number of chromosomes. For example, an egg contains 1 X chromosomes instead of 2. If it is involved in fertilization, the baby will have an extra X chromosome in every cell in her body.

There is a second mechanism of the defect occurrence, unrelated to the number of chromosomes in the egg or sperm. The embryo may develop abnormalities during cell division, leading to mosaicism. It is a phenomenon where only certain cells of the body contain one extra chromosome (47, XXX). The others have the correct number of chromosomes (46, XX)

When to see a doctor?

If you have any doubts or concerns about your daughter’s development, please consult your pediatrician or GP. Remember, however, that a visit to his office may be short. So let’s prepare well for it.

Write down all your daughter’s symptoms so far, even if they seem unrelated to the disease. Try to remember when the first developmental disorders appeared (e.g. when the daughter started talking, walking etc.). Write down all the relevant information about the course of the pregnancy, any illnesses you had during your pregnancy, and any medications you were taking at that time.

What can you expect when visiting a doctor?

Your doctor may ask you about this:

1) When did the first symptoms appear in your daughter?

2) Are there any mitigation / worsening factors?

3) Has the daughter developed properly so far? Did she start talking, walk at the expected age?

Many women never find out that their cells contain an extra X chromosome. This is because triple X syndrome is usually scanty or asymptomatic.

Is it possible to detect triple X syndrome in routine tests?

It is possible to diagnose triple X syndrome even before the baby is born. For this purpose, you can perform:

1) Chorionic villus sampling (CVS) – collection of a fragment of the villi of a part of the placenta (chorion).

2) Amniocentesis – the collection of a small amount of amniotic fluid in which the fetus is located.

3) Blood test – karyotype analysis is performed if the doctor finds abnormalities or delay in the development of the fetus (in ultrasound examination).

Each of these tests allows the analysis of the human karyotype (s). After the baby is born, a chromosome count analysis may be based on a blood test.

So far, there is no screening for triple X syndrome. If it is found it is usually during screening for other conditions (eg Down syndrome).

Need therapy?

Treatment for Triple X Syndrome depends on what, if any, symptoms are present and their severity.

If your daughter is diagnosed with triple X syndrome, treatment only focuses on symptomatic treatment. For example, if a child has learning difficulties, the professional help of a psychologist is necessary, just like any other child with a similar disorder.

If your daughter is diagnosed with triple X syndrome, the doctor may order periodic screening tests aimed at identifying symptoms of developmental delay (e.g. motor) as soon as possible and implementing e.g. rehabilitation as soon as possible.

Remember! The initial cause of this syndrome of defects, the doubling of the amount of genetic material, is incurable. However, considering that in many cases there are no symptoms or the symptoms are very scanty, a person with triple X syndrome can lead a perfectly normal life.

Text: MD Matylda Mazur

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