What are the causes and symptoms of testicular feminization?

As we all know, testicles are very important reproductive organs in the male body. If a man's testicles become feminized, it is obviously abnormal. Nowadays, most men have testicular feminization. So, what are the causes and clinical manifestations of testicular feminization? Please see the analysis of this issue below.

Androgen resistance refers to a group of clinical syndromes caused by the inability to fully exert the effects of androgens due to abnormal binding of androgen receptors and ligands or abnormal post-receptor signal transduction. According to the different degrees of peripheral tissue resistance to androgens, it is divided into complete androgen resistance and partial androgen resistance (PARS). Complete androgen resistance syndrome is also called testicular feminization syndrome.

Causes:

It is an androgen receptor mutation. The gene encoding the human androgen receptor is located on chromosome Xq11-22, is approximately 90KB, and contains 8 exons. The androgen receptor consists of three functional domains: a variable N-terminal transcriptional activation region, a highly conserved DNA binding region, and a moderately conserved C-terminal ligand binding region. After testosterone enters the cell, it is converted into dihydrotestosterone and binds to the receptor by 5α-reductase. Although testosterone itself can also bind to the receptor and produce an effect, the activation effect produced by dihydrotestosterone is stronger, 3 times that of testosterone. After the receptor binds to dihydrotestosterone, it enters the cell nucleus and binds to the androgen response element (ARE) to regulate the target genes of androgens.

Clinical manifestations:

The patient's chromosome karyotype is normal male type (46, XY), and the gonads are normal testicles. The external genitalia are normal female type, with poor development of the labia majora and blind vagina. Two-thirds of the patients have no uterus and fallopian tubes, and the remaining one-third only have remnants. The epididymis and vas deferens are generally absent. The testicles are located in the labia majora, inguinal duct or abdominal cavity. Testicular histological examination is normal before puberty. After puberty, the seminiferous tubules shrink, spermatogonia are scarce, no sperm occurs, and Reidy cells show adenomatous hyperplasia. The testicles have a tendency to develop malignant tumors.

During puberty, female secondary sexual characteristics develop, breast development is the same as that of normal women, female body shape, sparse pubic and axillary hair, primary amenorrhea, and normal intelligence.

Generally speaking, the feminization of male testicles is mostly related to the androgen receptor mutation in male patients. In clinical manifestations, the breast development of male patients with testicular feminization is very similar to that of females. In addition, their pubic and axillary hair will become less and less, and their body shape will also show feminine characteristics.