What Is Androgen Insensitivity Syndrome?

English androgen insensitirity syndrome

Androgen insensitivity syndrome

English androgen insensitirity syndrome

The androgen receptor gene is located near the centromere of the long arm of the human X chromosome, contains 8 exons, encodes 910 amino acids, has two zinc finger regions in the middle, and an androgen binding region at the C-terminus. Gene mutations in some areas can cause androgen insensitivity syndromes or testicular feminization. Individuals with clinical manifestations of XY karyotypes develop into seemingly normal but infertile women. The testes usually stay in the abdominal cavity. No spermatogenic process.

Androgen insensitivity syndrome is X-linked recessive inheritance with chromosome karyotype of 46, XY. It belongs to male pseudohermaphroditism. Its testosterone and urine 17 ketones are normal male values. The internal gonads are testis. Due to lack of 5a reduction in vulvar The enzyme, testosterone cannot be converted to dihydrotestosterone, or because of the lack of dihydrotestosterone receptor, and cannot express the androgen effect, feminization of the vulva.

Clinical classification of androgen insensitivity syndrome

In 1976, Prader et al. Divided patients with AIS (Androgen Insensitivity Syndrome, AIS) into complete types without masculine manifestations and incomplete types with masculine manifestations according to whether the patients had virilized manifestations.

1. Complete androgen insensitivity: They have lived as females since childhood. Individual patients in infancy can see a doctor because of a labia majora or groin mass. Sometimes during hernia repair, it is found that the contents of the hernia are testes. Adult clinical manifestations are more consistent: primary amenorrhea, female physique, puberty breast development, but breast

Androgen insensitivity syndrome, complete type

Poor head development, no or scarce yin and axillary hair, female vulva, labia minora, poorly developed vagina, blind end, no cervix and uterus, no menstrual cycle. The gonads can be located in the labia majora, groin, or peritoneal cavity. Patients often see a doctor for primary amenorrhea, labia majora, or inguinal mass. During the embryonic period, testosterone secreted by testicular mesenchymal cells in patients with AIS cannot stimulate the development of the Merfinian duct to form male internal genitalia due to abnormal androgen receptors. Dihydrotestosterone does not work on the genitourinary sinus and external genitalia and causes differentiation into the vagina Lower segment with female vulva. Testicular Sertoli cells secrete normal MIS, and Miller's canals are suppressed without the fallopian tubes, uterus, cervix, and upper vagina. After reaching puberty, due to the complete lack of androgen suppression, a small amount of estrogen can cause breast development and female body shape. Studies have found that AIS patients are 10 times more sensitive to estrogen than normal men.

2. Incomplete androgen insensitivity: The range of clinical manifestations of such patients varies greatly. The main difference from the full type is that there are different degrees of men

Androgen insensitivity syndrome, incomplete

, Including partial fusion of the enlarged clitoris and labia, puberty, axillary hair development. In 1947, Reifenstein reported an X-linked familial disease, mainly manifested as perineal scrotal hypospadias, breast development and infertility, and it has been found that it is also caused by androgen receptor defects. In 1979, Aimen et al. Reported that androgen receptor abnormalities were also found in patients with normal male phenotypes who had only primary infertility and azoospermia or oligozoospermia. ^[1]

Androgen insensitivity syndrome hormone changes

In normal men, the mesenchymal cells of the testis secrete testosterone by stimulation of the pituitary LH; testosterone, in turn, negatively regulates LH secretion. There are abundant androgen receptors in the hypothalamus and pituitary. Pre-pubertal AIS patients usually have LH and testosterone levels consistent with their age. The situation is similar in newborns and young children, but the peak LH and testosterone in normal male infants at the 6th week of birth do not appear in AIS patients. After puberty, testosterone secretion increases, and due to androgen receptor deficiency, the negative feedback of testosterone to the hypothalamus-pituitary system is insufficient, making the LH level of AIS patients higher than that of normal men; the secretion of FSH is the same as or increased in normal men. Increased LH stimulates the testes to secrete more testosterone and estrogen. Estrogen mainly comes from the testes, and a small amount is converted from androstenedione and testosterone by aromatization in peripheral tissues. Because elevated LH increases the stimulation of mesenchymal cells, the production of estrogen is approximately twice that of normal men. As a result, AIS testosterone and estrogen are at normal high limits or elevated after puberty. After HCG stimulation, there was a normal increase in blood testosterone and DHT.

Pathological characteristics of testes in androgen insensitivity syndrome

The typical testis and its associated tissue specimens of this type of patients have three components: the testicles often have multiple brown or white nodules; a white thread-like hard smooth muscle body fused on the midline of the testis; beside it There are accessory cysts of varying sizes.

There are one of the following four changes under testicular parenchyma: diffuse tubular interstitial; lobular tubular interstitial; mixed tubular interstitial; interstitial dominated.

Most of the testicular mesenchymal cells are in a proliferative state, the seminiferous tubules are obviously atrophied and stiff, and they are filled with immature support cells, and most of them have no spermatogenesis. Muller reports that the testicular pathology of AIS patients younger than 5 years is the same as that of non-decreased testes, and the number of germ cells is normal. ^[1]