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Genetic Category |
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Intersexed Links @ Open Directory
Intersexed Resources #1, Intersexed Resources #2
| Biologically speaking, the pathway towards a female form seems to be the default for humans, while the path for development of a male fetus is more tortuous, and dependent on many different genes, each of which can be faulty. This means that there is a set of a fairly varied conditions in which a fetus with XY chromosomes develops as a baby girl. |
| 1.Failure of formation of testes due to a variety of reasons (i.e. Swyer syndrome or pure XY gonadal dysgenesis, XO/XY mosaicism, testicular regression syndrome etc.). 2.Underdevelopment of cells in testes due to unresponsiveness to hormones from the pituitary gland (i.e. Leydig cell agenesis or hypoplasia).
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| Caused by prenatal exposure to exogenous androgens, most commonly
progestin.
Progestin is a drug which was administered to prevent miscarriage in the
50's and 60's and it is converted to an androgen (virilizing hormone) by
the prenatal XX persons metabolism. If the timing is right, the genital
anlagen is virilized with effects ranging from enlarged clitoris to the
development of a complete phallus and the fusing of the labia. The virilization
only occurs prenatally and the endocrinological functionality is unchanged, ie. feminizing puberty occurs due to normally functioning ovaries.
In other words, XX people affected in-utero by virilizing hormones can be born into a continuum of sex phenotype which ranges from "normal female with large clitoris" to "normal male with no testes". It is noteworthy that the use of progestin is not effective in the prevention of miscarriage. D.E.S. aka Di-Ethyl-Estrobial also made inutero changes to babies, interferring with their development of their sex.
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Swyer's Syndrome (Complete 46,XY Gonadal Dysgenesis) If the gonad fails to progress beyond the indifferent stage, it may produce no testosterone Swyer's Syndrome, complete 46 XY gonadal dysgenesis, swyer syndrome, swyers syndrome. Complete XY gonadal dysgenesis usually is diagnosed when a healthy girl of normal stature becomes concerned in her midteens about lack of pubertal development. Eunuchoid skeletal proportions may be found, and the bone age will be delayed Swyer's Syndrome, complete 46 XY gonadal dysgenesis, swyer syndrome, swyers syndrome. Primary gonadal failure is indicated by elevated levels of serum follicle-stimulating (FSH) and luteinizing hormone (LH) and a low plasma estradiol level. Pelvic ultrasound shows the presence of a small uterus, but the Chromosomal mosaicism is the cause in most cases; however, in the last 8 years, several genes that regulate gonadal differentiation and testis determination have been discovered, and mutations in several of them have been found in association with gonadal dysgenesis. In 10% to 15% of cases, complete 46,XY gonadal dysgenesis is caused either by a mutation in the SRY gene or by a Yp deletion of the pseudoautosomal junction region in All patients with CYP17 (also called P450 c17 or 17alpha-hydroxylase) deficiency are female regardless of whether they are XX or XY, because there is a complete block in the biosynthesis of androgens and estrogens both prenatally and postnatally. Adrenal hyperplasia results from impairment of cortisol biosynthesis and a secondary elevation in ACTH secretion. Consequently, the secretion of both desoxycorticosterone and corticosterone is greatly elevated, causing hypertension and hypokalemia. Renin activity and circulating aldosterone are Treatment with dexamethasone reduces ACTH secretion and therefore the levels of desoxycorticosterone and corticosterone, and blood pressure returns to normal. Estrogen is given from age 11 years to 46,XY patients who have no uterus and in combination with cyclical progestogen to 46,XX patients who do have a uterus. Low-dose testosterone is given to induce pubic hair development. The ovaries of 46,XX patients contain numerous follicles. In one case in which testosterone was provided as an aromatizable substrate, follicular maturation could be induced, but fertilization proved impossible. Numerous mutations in the gene for CYP17 have been demonstrated in patients with deficiency. Several have been expressed in COS cells, and these show that the In this rare disorder, affected XX and XY infants are phenotypic females who lack the ability to secrete any adrenal or gonadal steroids owing to a complete block in cholesterol side-chain cleavage. Salt loss becomes clinically evident within a week of birth, and severe hypoglycemia may also occur. The lips and genitalia are often deeply pigmented. Because of the apparent absence of cholesterol side-chain cleavage enzyme activity, it was assumed that the defect would reside in the gene encoding P450 scc (CYP11A); however, when this gene was cloned, it was found to be structurally normal in all cases of lipoid adrenal hyperplasia. Subsequently, mutations were found in the gene encoding the steroidogenic acute regulatory protein (StAR). This protein regulates the transport of cholesterol into the mitochondrion where it can be acted upon by P450 scc (CYP11A).
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| MRKH stands for Mayer-Rokitansky-Kuster-Hauser Syndrome, named after four men who studied this birth defect. It is a defect wherein a woman is born without a uterus, cervix, and, in many cases, a vagina, and therefore cannot reproduce. The woman is also likely to be missing one kidney |
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MRKH Syndrome Links http://ncnc.essortment.com/mayerrokitansky_rknh.htm http://www.execpc.com/~pdefrain/ http://www.surrogacy.com/online_support/mrkh/
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