Testicular feminization syndrome (or Morris syndrome) is a disease that occurs when the tissues are totally or partially unaffected by androgens.
At the same time a person with normal male genotype (a set of genes) and the presence of chromosomes X and Y forms a female phenotype (appearance). Moreover, the appearance of these women can not even be suspected of having Y-chromosomes in them. A case when this diagnosis was put to a girl who in the sixties of the last century became a Miss of the World.
Why is this happening?
The reason for such an immutability of peripheral tissues to hormones is the congenital pathology of the receptors, due to mutation in the gene of the androgen receptor. There is a pathology in one of 50-70 thousand newborns. This syndrome refers to hereditary diseases linked to a recessive type X-chromosome.
Depending on the degree of insensitivity of the androgen receptors, there is a complete form of testicular feminization (with complete insensitivity to androgens) and incomplete form (when the sensitivity is initially partially preserved or partially restored in the puberty period).
Why do newborns look like girls in spite of the male genotype
In the process of embryogenesis of gonads in the syndrome of testicular feminization at the seventh week of intrauterine development under the influence of the Y chromosome are differentiated as a full-fledged functioning testicle. In order for the primary sexual characteristics to be formed by the male type, androgens are required.
Under the influence of two hormones (testosterone and dehydrotestosterone), the penis, scrotum, urethra and prostate gland (prostate) are formed. However, due to a defect in the tissue of the tissues of the patients, they are insensitive to androgens, but sensitivity to estrogens is preserved.
This leads to the regular formation of the female phenotype. Female internal genital organs (uterine tubes, uterus and upper third of the vagina) are absent in such patients, as in the testicles a factor inhibiting their development is synthesized.
The testicles can be located either in the abdominal cavity, or in the inguinal canals or large labia. In the intra-abdominal localization of the testes, a very high probability of their malignant degeneration, which increases with age.