- XX gonadal dysgenesis
Name = PAGENAME
OMIM = 233300
OMIM_mult = XX gonadal dysgenesis
OMIM2|233400 Perrault syndrome
OMIM2|306100 Swyer syndrome
MeshID = D023961
XX gonadal dysgenesis is a type of female
hypogonadismin which no functional ovaries are present to induce pubertyin an otherwise normal girl whose karyotypeis found to be 46, XX. With nonfunctional "streak" ovaries she is low in estrogen levels (hypoestrogenic) and has high levels of FSHand LH. Estrogenand progesteronetherapy is usually then commenced.
XX GD as a form of "pure gonadal dysgenesis"
The term “pure gonadal dysgenesis” (PGD) has been used to distinguish a group of patients from gonadal dysgenesis related to
Turner syndrome. In the latter a distinct chromosomal aberration is present, while in PGD the chromosomal constellation is either 46, XX or 46, XY. Thus XX gonadal dysgenesis is also referred to as "PGD, 46 XX", and XY gonadal dysgenesis as "PGD, 46, XY" or Swyer syndrome. [ [http://www.medscape.com/viewarticle/499501_5 Log In Problems ] ] Patients with PGD have a normal chromosomal constellation but may have localized genetic alterations.
The cause of the condition is often unclear. There are cases where abnormalities in the
FSH-receptorhave been reported. [Aittomaki, K.; Lucena, J. L. D.; Pakarinen, P.; Sistonen, P.; Tapanainen, J.; Gromoll, J.; Kaskikari, R.; Sankila, E.-M.; Lehvaslaiho, H.; Engel, A. R.; Nieschlag, E.; Huhtaniemi, I.; de la Chapelle, A. : Mutation in the follicle-stimulating hormone receptor gene causes hereditary hypergonadotropic ovarian failure. Cell 82: 959-968, 1995. PMID 7553856] Apparently either the germ cells do not form or interact with the gonadal ridge or undergo accelerated atresiaso that at the end of childhood only a streak gonad is present, unable to induce pubertal changes. As girls' ovaries produce no important body changes before puberty, there is usually no suspicion of a defect of the reproductive system until puberty fails to occur. Familial cases of XX gonadal dysgenesis are on record.
1951, Perrault reported the association of gonadal dysgenesis and deafness, now called Perrault syndrome. [Perrault, M.; Klotz, B.; Housset, E. :Deux cas de syndrome de Turner avec surdi-mutite dans une meme fratrie. Bull. Mem. Soc. Med. Hop. Paris 16: 79-84, 1951.]
Because of the inability of the streak gonads to produce
sex hormones (both estrogens and androgens), most of the secondary sex characteristics do not develop. This is especially true of estrogenic changes such as breast development, widening of the pelvis and hips, and menstrual periods. Because the adrenal glands can make limited amounts of androgens and are not affected by this syndrome, most of these girls will develop pubic hair, though it often remains sparse.
delayed pubertyusually reveals the presence of pubic hair, but elevation of gonadotropins, indicating that the pituitary is providing the signal for puberty but the gonads are failing to respond. The next steps of the evaluation usually include checking a karyotypeand imaging of the pelvis. The karyotype reveals XX chromosomes and the imaging demonstrates the presence of a uterus but no ovaries (the streak gonads are not usually seen by most imaging). At this point it is usually possible for a physician to make a diagnosis of XX gonadal dysgenesis.
The consequences to the girl with XX gonadal dysgenesis:
# Her gonads cannot make estrogen, so her breasts will not develop and her uterus will not grow and menstruate until she is given
estrogen. This is often given through the skin now.
# Her gonads cannot make progesterone, so her menstrual periods will not be predictable until she is given a
progestin, still usually as a pill.
# Her gonads cannot produce eggs so she will not be able to conceive children naturally. A woman with a uterus but no ovaries may be able to become pregnant by implantation of another woman's fertilized egg (
The XX gonadal dysgenesis is the related to the
Swyer syndromeinasmuch as both conditions have the same phenotype and clinical issues, however in Swyer syndrome the chromosome constellation is 46, XY, and thus requires gonadectomy.
Turner syndromethere is a demonstrable abnormality in or absence of one of the sex chromosomes that is the cause of the development of gonadal dysgenesis. In contrast XX gonadal dysgenesis has a normal female chromosome situation.
Another type of XX gonadal dysgenesis is known as 46 xx gonadal dysgenesis epibulbar dermoid, which follows the similar symptoms as the regular syndrome, though it also shows signs of
epibulbar dermoid(eye disorder).cite journal |author=Quayle SA, Copeland KC |title=46,XX gonadal dysgenesis with epibulbar dermoid |journal=Am. J. Med. Genet. |volume=40 |issue=1 |pages=75–6 |year=1991 |pmid=1909490 |doi=10.1002/ajmg.1320400114] [RareDiseases|5671|46,XX Gonadal dysgenesis epibulbar dermoid] [ [http://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=GB&Expert=1771 ORPHANET - About rare diseases - About orphan drugs ] ] It has been suggested to be a new type of syndrome.
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