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Turner syndrome It is defined as a genetic disorder caused by an alteration (by total or partial absence) of the X chromosome. Humans have 46 chromosomes, which are small structures shaped containing genetic information or DNA that are present in the nucleus of all the plant and animal cells. Of these 46 chromosomes, there are two that determine the sex of individuals: the X and the and. Women have two chromosomes X, one inherited from the father and the other from the mother. For their part, men have an X chromosome inherited from the mother and one chromosome and inherited from the father.
Therefore, this genetic disease only affects girls, since children, having only one X chromosome, the total or partial absence of the same would be incompatible with life.
Exact cause why this chromosomal disorder occurs is not known, although they are running two possibilities. On the one hand, it could be due to an error in the division of sex cells (meiosis), occurred at the time of forming the egg or sperm, making that one of the two does not carry the X chromosome. On the other hand, also the option that chromosome loss occurs later, in the division of the already fertilized (mitosis), immediately Shuffle after conception. The frequency with which this syndrome occurs in the population is 1 between 2,500 new female live births.
Turner syndrome named after Dr. Henry Turner, doctor who described it for the first time in 1938. This disorder is also known as syndrome 45, X; Bonnevie-Ulrich syndrome; Morgagni-Turner-Albright syndrome or Monosomy X, among many others.

Symptoms of Turner syndrome

These are the typical clinical features of a case of a patient with Turner syndrome:
  • Stature, generally less than 1.60 meters.
  • Defective formation of ovaries and internal female organs, as well as absence of ovules (gonadal dysgenesis and infertility).
  • Child appearance of the external genitalia and sometimes malformations in them.
  • Shield-shaped chest.
  • Cardiac and renal malformations.
  • Flabby folds in the back of the neck, which is known as "webbed neck" or pterigium colli.
  • Alteration in the alignment of the bones of the forearm. What produces a cube valgus or displacement of the forearm out.
  • Low implantation of hair.
  • Increase in volume or swelling of hands and feet.

Diagnosis of Turner syndrome

Most suspected cases of Turner syndrome is diagnosed by pediatricians, because they know the clinical features of these patients. What startles most is the stature, the increase in volume of hands and feet, webbed neck, hairline line low at the neck and the cubitus valgus (the displacement of the forearm out).
The most important diagnostic test to be performed at the suspicion of a case of Turner syndrome is the karyotype, which is defined as a pattern of the chromosomes of a species. To make this test a sample of the patient's blood is taken and grown in the laboratory. About 50% of patients with Turner syndrome have the pattern 45, XO , that lack them an X chromosome. Later, more frequent findings are partial losses of pieces of chromosomes (deletions), or a full arm of chromosome X or mixture of several of them in different cells (what is known as mosaic).
When he has already confirmed the diagnosis of Turner syndrome, should be more in-depth molecular genetic studies to determine if the patient has genes of chromosome and, when it is present there is an increased risk (of 15-25%) develop tumors as gonadoblastoma or the dysgerminoma in the male pseudogandula, i.e. what would have been the testicles, surgical excision is recommended.
Other complementary tests for the diagnosis of Turner syndrome are the x-ray of wrist to calculate bone age a cardiological assessment by echocardiography to detect malformations, a hearing test, and an abdominal and pelvic ultrasound to evaluate renal malformations and reproductive organs.

Prenatal diagnosis

It occurs before birth by the analysis of fetal cells, which can be achieved by conducting various tests:
  • Chorionic biopsy: in this technique, the fetal cells, from the villus sampling which originate the placenta, are obtained by cell culture. This is done between the ninth and the twelfth week of pregnancy.
  • Amniocentesis - consisting of a puncture through the wall of the uterus to remove amniotic fluid (which float fetal cells) - can be performed between weeks 14 and 16 of pregnancy.
  • And finally, with the funiculocentesis or direct puncture of the umbilical cord, to obtain blood from the fetus. It can be from the 20th week of gestation.
An ultrasound study it can be suspected that the fetus is affected of Turner syndrome; the most common abnormalities are cystic hygroma (filled cavity of lymphatic fluid) in the neck of the fetus, in 88% of cases; hydrops (abnormal accumulation of fluid), 80%; short femur, in 59% of the patients; malformations in the heart, at 48%; and brachycephaly (flattening of the bones of the skull), 32% of those affected.

Treatment of Turner's syndrome

Patients with Turner's Syndrome should be evaluated and treated regularly by a multidisciplinary group composed of various specialists: pediatrician, surgeon, nephrologist, cardiologist, psychologist, nutritionist... The most relevant aspects are covered in the following way:
  • The stature, one of the major clinical problems of Turner syndrome, is treated with growth hormone (while the patients produce this hormone). This hormone has been developed by genetic engineering and is equal to the growth hormone that we synthesize in our body. It is often recommended the daily application of a subcutaneous injection, you must start these injections from four years of life. If not this hormone is given the final size in patients with Turner syndrome can be up to 20 cm less than that of the rest of the female population, but if growth hormone is administered properly this difference it can be reduced to only five or six centimeters less. There are other treatments that can be applied together with growth hormone which consists of the surgical limb lengthening or bone lengthening. The evolution natural of the carving in the patients with syndrome of Turner has a pattern typical:
    • Prenatal growth (inside the womb) phase: happens retardation of growth so that at birth have a size that is two to three centimeters less than the of the other newly born female.
    • Newborn stage and first year of life: during this stage is still delaying its growth in relation to the size by which never reach the percentile on the growth charts of development for their age and sex. The first year they have about 10 centimeters less than the rest of the girls.
    • Preschool and school stage: maintain the situation of growth retardation.
    • Stage preadolescence and adolescence: arriving 12 years approximately, the size of these girls is below the average and during the development stage there is the typical lug, since they do not produce hormones that are needed to make it happen.
    • Young adult stage: despite being with a stature that the rest of the girls, the growth process stays active longer and this happens for a delay in the closing of ossification points, this results in patients with Turner syndrome can continue won until the age of 19 to 20 cm approximately.
  • In relation to the problems of development must administer treatment with estrogen between 13 and 14 years to make happen the menarche (onset of menstruation), for the development of secondary sex characteristics, in order to reduce the risk of osteoporosis and reduce the risk of vascular disease. Estrogens may be administered through pills, intradermal implant patches in skin... When menstruation occurs (approximately two years later) progestins are added to treatment, making this cyclic. Despite this therapy, women with Turner syndrome usually do not become pregnant spontaneously, with subsequent infertility, however can have children through the techniques of fertilization in vitro (embryo transfer) with the same ease as another woman.
  • The stature and the failure in the ovaries are risk factors for osteoporosis, why must ensure a good supply of calcium and vitamin D.
  • If the patient presents many alterations in face and neck the possibility of plastic surgery should be discussed to attenuate these traits.
  • Weight and diet must be monitored to reduce the risk of obesity and associated diabetes, if you arrive to occur can be treated with oral hypoglycaemic.
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