Mechanism of Turner syndrome
1. What is Turner syndrome?
Turner syndrome and pediatrics are closely related. Normally, more than 90% of fetuses with Turner syndrome will have a spontaneous abortion, but still about 1 in 4,000 girls are born with this syndrome.
2. What causes Turner syndrome?
In Turner syndrome, due to the complete loss of 1 X chromosome, there is only one X sex chromosome left, this is the most common cause, accounting for about 50%. This case HC Turner is also known as monosomy X, denoted by 45,X or 45,X0.
About one-third of women with Turner syndrome have both X chromosomes, but one is missing a segment.
There are also many cases of patients with Turner syndrome having mosaicism. In their body, there are 2 cell lines that exist in parallel, 1 normal cell line 46,XX and 1 abnormal cell line 45,X. These mosaic cases are more fortunate, often causing milder disorders than Turner syndrome due to the abnormality of partial or complete absence of a true X chromosome.
Sometimes there are also cases of mosaic Turner syndrome with the existence of a cell line containing a part of the Y chromosome that determines the male sex. However, the Y chromosome part is not much, so the male sex phenotype is not generated for the patient. These women have an increased risk of ovarian tumors.
Recently, scientists have identified the SHOX gene located at the short end of the X chromosome, which is mainly a consequence of the loss of a SHOX gene, causing dwarfism.
HC Turner is not curable, but can be diagnosed early in pregnancy to avoid having a baby with Turner.
3. Manifestations of people with Turner syndrome
3.1 Small figure
If the patient does not have hormone replacement, the patient will continue to grow slowly without the possibility of the growth spurt during puberty. Through many surveys, women with Turner syndrome are usually about 20cm shorter than the average person.
3.2 Premature ovarian failure
The ovaries are the only place in the body that has the function of producing eggs and female sex hormones to develop the characteristics of the female body such as: physique, breasts, menstruation, female skeletal system.
On average, only about one-third of people with Turner will show signs of breast development, but most do not complete puberty. In particular, less than 1% of patients can get pregnant naturally.
4. Turner syndrome can be diagnosed early in the fetus
Some traditional diagnostic testing methods such as chromosomal testing performed on amniotic fluid cells have a high detection rate, but still have complications, affecting the fetus. Currently, there is a modern non-invasive prenatal screening method NIPT, which helps to test fetal DNA in maternal blood safely, early detection from the 10th week of pregnancy, high accurate diagnosis rate should be trusted.
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