It is a monosomy in which affected individuals exhibit female sex but generally do not have sexual chromatin.
Examination of its karyotype commonly reveals 45 chromosomes, and of the pair of sex chromosomes there is only one X; we say these individuals are XO (x-zero), their karyotype being represented by 45X. Many of these conceptions end in abortion; 97% of these concepts are likely to be eliminated to just 3%, so this monosomy is one of the most common causes of intrauterine death. It is therefore a rare chromosomal anomaly, affecting only 1 in 3000 normal women.
These are mainly women with gonadal dysgenesis, that is, whose ovaries are atrophied and devoid of follicles; therefore, these women do not breed except in a few reported cases of fertile Turner, in whose ovaries there are certainly some follicles.
Due to estrogen deficiency they do not develop secondary sexual characteristics upon reaching puberty and are therefore easily identified by the lack of these characters; thus, for example, they do not menstruate (ie, they have primary amenorrhea). When adults usually present shortnot more than 150 cm; genital infantilism - small clitoris, large depigmented lips, pubic hair shortage; android pelvis, that is, masculinized; loose skin due to scarcity of subcutaneous tissues, which gives it a senile appearance; narrow nails; broad and barrel-shaped chest; cardiac and bone changes. In the newborn there is often edema in the hands and feet, which leads to suspicion of the anomaly.
Early observations of severely affected individuals associated Turner syndrome with some degree of mental disability. It was later evident that these patients have only qualitatively altered cognitive development, as they have a higher verbal intelligence than normal women, thus compensating for their deficiencies in form-space perception. As a result, the Turner's global intellectual level is at or even slightly higher than the normal female population.
On the other hand, they do not exhibit personality deviations, which means that their psychosexual identification is not affected. Due to ovarian dysgenesis, the only source of estrogen for these people is the adrenals; Because the rate of these hormones is low, patients should receive estrogen applications to stimulate the development of secondary sex characters and the onset of menstruation. Usually this treatment begins at age 16 to prevent the applied estrogens from further retarding growth.