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Errors in Gonadal Differentiation and Development

To describe the causes and manifestations of errors in differentiation and development of the gonads.

True Hermaphroditism
-What types of gonadal tissue do true hermaphrodites possess?
-What type of internal reproductive tract is characteristic of true hermaphrodites?
-What is the appearance of the external genitalia of true hermaphrodites?

Ovarian Dysgenesis
-What is the name of the most common form of ovarian dysgenesis?
-Describe the ovaries of patients with this disorder.
-What is the most common karyotype in this disorder?
-What are eight common characteristics of patients with this disorder?
-Would a patient with this disorder have normal ovarian function?
-Would plasma levels of reproductive hormones be high, low or normal?

Seminiferous Tubule Dysgenesis
-What is the name of the most common form of seminiferous tubule dysgenesis?
-What are the minimal numbers of X and Y chromosomes that define this disorder?
-What is the frequency of this disorder?
-What are the gonadal manifestations of this disorder?
-What are the four principal characteristics of this disorder which lead one to
 suspect this disorder in prepubertal boys?

True Hermaphroditism


True hermaphrodites possess both ovarian and testicular tissue, either separately or as one or more ovotestes. Gonadal tissue may be located in the ovarian, inguinal or labioscrotal region. The likelihood of an ovotestis descending is proportional to the amount of testicular tissue present. Normal oocytes, but rarely spermatozoa are seen. Most true hermaphrodites have a 46 XX chromosomal compliment but others may have a mosaic that is 46 XX, 46 XY etc complement.

Androgens, estrogens and progestins are synthesized in the gonads of true hermaphrodites. True hermaphroditism presumably results from chimerism i.e two or more cell lines derives from different zygotes in a single individual. True hermaphrodites usually have a bicornuate or unicornuate uterus external genitalia are either predominantly female or ambiguous. Breasts usually develop at puberty, if the uterus is present a true hermaphrodite usually will menstruate and can become pregnant, after removal of testicular tissue.

In the past approximately 2 thirds of true hermaphrodites were raised as males currently gender assignment is a topic of considerable discussion. In the past going adult tissue was biopsied and tissue not compatible with the gender assignment was removed currently treatment of hermaphrodites is under reconsideration.

Ovarian Dysgenesis


Most Turner syndrome patients have a 45, X karotype referred to as monosomy X. About 99% of all 45, X embryos spontaneously abort. Turner syndrome patients have decreased levels of estrogen and androgens and increased levels of FSH and LH. Most Turner syndrome patients have a 45, X karotype. About 70 percent of live-born 45, X individuals have lost a paternal sex chromosome.

Some of the notable features of Turner syndrome patients are, small but well-differentiated external genitalia, uterus and vagina. Short statured. Webbed neck. Shield like chest. Hypoplastic nails. Epicanthal folds. High arched palate. Coarctation of the aorta. Ventricular septal defect. Cubitus valgus. Short 4th metacarpal and low birth weight. Turner syndrome patients lack secondary sexual development at puberty with decreased pubic and axillary hair occasionally.

Turner syndrome patients menstruate and are fertile. Turner syndrome patients identify as female. Treatment options include growth hormone and estrogen to stimulate growth, closure of epiphyses and pubertal development.

Seminiferous Tubule Dysgenesis


In Klinefelter syndrome there is at least one Y chromosome and atleast 2 X chromosomes. Klinefelter syndrome patients have androgen deficiency with elevated gonadotropin levels. The most common cause of Klinefelter's syndrome is an extra X chromosome. Some of the notable features of Klinefelter's Syndrome patients are sparse facial hair, rare adolescent acne, small firm testes less than 1.5 centimeters in postpubertal individuals, well differentiated external genitalia, though neonates may have a small penis, smaller than normal prostate, poor muscle development, pale wrinkles skin, female fat distribution, moderate bilateral gynecomastia and slightly taller than normal males with relatively long legs compared to the trunk and arms.

Klinefelter syndrome patients undergo seminiferous tubule dysgenesis, in which Sertoli cells proliferate shortly before the expected time of puberty and thenseminiferous tubule degenerate. Leydig cells are structurally normal but produce decreased amounts of androgens. There is a lack of normal secondary sexual development due to androgen deficiency and a lack of lowering of the voice.

Klinefelter syndrome patients are identifiably male. Treatment for Klinefelter's Syndrome is testosterone therapy.