Turner syndrome: symptoms, types, causes and treatment

Monosomies are a type of chromosomal abnormality in which some or all of the body's cells contain a single pair of chromosomes that should be duplicated. One of the few human monosomies compatible with life is Turner syndrome, in which the defect occurs in the female sex chromosome.

In this article we will describe the symptoms and causes of the main types of Turner syndrome, as well as the therapeutic options that are commonly used in these cases.

• You may be interested in: "Edwards syndrome (trisomy 18): causes, symptoms and types"

What is Turner syndrome?

Turner syndrome is a genetic disorder that appears as a consequence of random alterations in the X chromosome. It does not usually affect the intelligence, so people with this disorder generally have normal IQs.

It is related to the presence of a single X chromosome in cases where there should be two, so the Turner syndrome is diagnosed almost exclusively in girls, although there is a subtype that appears in males. It occurs in about 1 in 2,000 female births.

This alteration affects physical development, especially because of its inhibitory effects on sexual maturation: Only 10% of girls with Turner syndrome show some signs that they have reached puberty, while only 1% have babies without medical intervention.

• You may be interested in: "Fragile X Syndrome: Causes, Symptoms, and Treatment"

Main symptoms and signs

Girls and women with this disorder have two characteristic features that are the core of the diagnosis: your height is shorter than normal and your ovaries are not fully developed, so they have amenorrhea or menstrual irregularity and cannot become pregnant.

Because the basic signs of Turner syndrome are related to biological maturation and the sexual development, it is not possible to definitively identify the presence of this disorder at least until the puberty, period in which these signs begin to manifest clearly.

The rest of the usual symptoms of Turner syndrome vary depending on the case. Some of the most common are the following:

• Morphological abnormalities of the face, eyes, ears, neck, limbs, and chest
• Swelling from fluid accumulation (lymphedema), often in the hands, feet, and neck
• Visual and hearing problems
• Growth delays
• Puberty does not complete spontaneously
• infertility
• Short stature
• Heart, kidney and digestive disorders
• Deficits in social interaction
• Learning difficulties, especially in mathematical and spatial tasks
• hypothyroidism
• Scoliosis (abnormal curvature of the spine)
• Increased risk of diabetes and heart attacks
• Hyperactivity and attention deficit

Types and causes of this disease

Turner syndrome is due to the absence of one of the two X sex chromosomes in people of the female biological sex, although sometimes it also appears in males who have an incomplete Y chromosome and who therefore develop as women.

Three types of Turner syndrome have been described depending on the specific genetic causes of the symptoms. These chromosomal alterations occur at fertilization or during the initial stage of intrauterine development.

1. by monosomy

In the classic variant of this syndrome the second X chromosome is totally absent in all the cells of the body; due to defects in the egg or sperm, the successive divisions of the zygote reproduce this basic anomaly.

2. with mosaicism

In mosaic-type Turner syndrome, an extra X chromosome can be found in most cells, but it is either not complete or defective.

This subtype of the syndrome develops as consequence of impaired cell division from a certain point in early embryonic development: cells arising from the defective lineage do not have the second X chromosome, while the rest do.

3. With incomplete Y chromosome

In some cases, individuals who are genetically male do not develop normatively because the Y chromosome it is absent or has defects in part of the cells, so they look feminine and they may also have the symptoms that we have described. It is a rare variant of Turner syndrome.

Treatment 

Although Turner syndrome cannot be "cured" because it is a genetic variation, there are different methods that can resolve or at least minimize the main symptoms and signs.

Morphological alterations and other similar associated defects tend to be difficult to modify, although this depends on the specific alteration. Depending on the case, the intervention of specialists such as cardiologists, endocrinologists, otolaryngologists, ophthalmologists, speech therapists or surgeons, among others, may be necessary.

In cases where this disorder is detected early, growth hormone injection therapy promotes the achievement of a normal height in adulthood. Sometimes they are combined with low doses of androgens in order to enhance the effects of this treatment.

with great frequency hormone replacement therapies are applied girls with Turner syndrome when they reach puberty to enhance their biological maturation (p. and. to promote the onset of menstruation). Treatment is usually started with estrogen followed by progesterone.