What happens in the embryo
The sexual differentiation in the human embryo is in itself the differentiation in the masculine sense, since the sex by default is the feminine; this means that in order for the masculine embryo to develop, the natural path that would lead the embryo to differentiate itself in the feminine sense must be deviated.
This is achieved from the product of a gene, the SRY gene, found in the Y chromosome of males, which among its most important actions, stimulates the persistence of the primary sexual cords, which is synonymous with the transformation of the undifferentiated gonad into the testicle, since if they were to atrophy, they would be replaced by the secondary sexual cords, characteristic of the ovary.
Once the gonad of the embryo has differentiated into testicle, we can find in it the cells of Sértoli and Leydig, each one with important functions in this mechanism of differentiation in the
The cells of Sértoli produce anti-müllerian hormone (HAM) that induces the involution of the Müller’s duct (Muller 1832) The cells of Leydig synthesize androgens (testosterone) that fulfill a double function in this mechanism: on the one hand they stimulate the persistence and development of the Wolff’s ducts (Caspar Wolff, 1820) and on the other hand they stimulate the external genitals.
In the female embryo, in the ovary, we do not find either of these two cell types, therefore there will be no AMH, therefore there will be no atrophy of the Müller’s duct and in the absence of androgens, if Wolff’s duct disappears (due to lack of testosterone) in this way, the external genitals will evolve in a female sense.
It is surprising how many disorders and pathologies there are, due to these complex waterfalls that exist for the generation of hormones, such as Morris syndrome or male pseudohermaphroditism, since it is a disease where the affected individual has a genotype and phenotype (inherited characteristics and external appearance) of different sexes, it would be like the case of a congenital transgender, figuratively speaking, by natural causes, without any external agent intervening.
This syndrome is defined as a physical abnormality, in which a person has the genetics of one sex (male) and the genitals of another (female). This is also known as (SIA): androgen insensitivity syndrome (testosterone), due to the absence of receptors.
The abnormality is due to the fact that men are resistant to male hormones, i.e. androgens (testosterone in between). This causes the development not only of the genital organs of the other sex, but also the appearance will be that of a woman and no one will realize that there is a pathology, until adolescence, in which menstruation will not appear, therefore the sexual assignment will be female, from birth.
They will have female traits, female sexual organs or similar, testosterone with levels similar to those of men, but due to the pathology androgens cannot act normally.
Morris syndrome( described 1953) is a rare disease (it was described as testicular feminization syndrome), affecting only 1 in 40,000 babies born. However, because only a few cases are known, it is possible that the prevalence is even higher and is considered to be the third leading cause of amenorrhea at puberty.
In the severe form, the genitals are female but sometimes they may present problems such as a smaller size of the vagina, and no connection to another organ, with hypoplasia of the lips of the vagina, most of which have testicles, but these have not descended and remain in the abdomen. These are usually removed when the diagnosis is made to prevent the development of cancer in the future.
Underarm or pubic hair does not appear (or appears sparsely) in affected persons. At puberty there is no menstruation, since they are genetically male, and the affected individuals are infertile, since neither the ovaries nor the uterus have developed.
Causes of Morris syndrome:
The disease is hereditary in nature, where there is a mutation in a gene, called RA, which is found on the X chromosome, since males only have one X chromosome, it is easier for them to develop the disease, since the female can carry the mutation of the gene, and transmit it to a child…. What causes the problem is the absence of receptors, which are the AR proteins (androgen receptors), which do not allow to act in conjunction with testosterone for male formation or development, which means that the person is resistant to testosterone.
To explain the process in a much simpler way, it should be noted that females have the XX chromosomes, while males have the XY chromosomes. Its main difference is that men produce testosterone and this hormone is responsible for the development of the male individual. When the body is absent from it (in this case there is, generated by the embryo itself, but it is as if there were not, since there are no receptors, it is transformed into estrogen), then the individual develops as a woman externally, even though inside it is still male, in its genes.
Diagnosis of Morris syndrome:
The diagnosis is usually not made during the individual’s childhood, since at that time he or she does not yet have symptoms that indicate that he or she has this disease. It is at the stage of puberty when the problem is evident, where doctors may perform different tests to diagnose the person:
A chromosomal study can confirm the existence of the karyotype 46 XY, characteristic of people with the syndrome, because the vagina is usually blind and smaller, with the help of a gynecological ultrasound, the absence of the uterus and ovaries could be observed.
People affected with the syndrome receive three treatments: dilation therapy, gonadectomy and psychological therapy that will help the patient feel comfortable with his or her body, as it should be and avoid absurd complexes.
At puberty, female sexual characteristics develop, reaching a total female appearance, by the action of estradiol, which is generated from testosterone, which is transformed by the action of an enzyme called aromatase.