Genetic Related Developmental Sex Disorders Flashcards
What is aneuploidy?
Unequal distribution of one pair of homologous chromosomes to the daughter cells
When does aneuploidy occur?
When daughter sex cells split
What is mosaicism?
Nondisjunction during early cleavage of the zygote
When does mosaicism occur?
When zygotes split
What does every extra X chromosome found in a human cause?
Adds a 15% chance of retardation for each extra X
What is a true hermaphrodite?
Has both testes and ovaries in the same body (can be contained in the same structure or separate)
What is a pseudohermaphrodite?
Male with testes but wrong external genitalia or female with ovaries but wrong external genitalia
What aneuploidy disorders occur in females?
Turner’s Syndrome 45 XO
47 XXX
What aneuploidy disorders occur in males?
Klinefelter’s Syndrome 47 XXY
47 XYY
What sex genetic mutations occur only in females causing pseudohermaphroditism?
Congenital adrenal hyperplasia
What sex genetic mutations occur only in males causing pseudohermaphroditism?
Testosterone insensitivity
5a-reductase deficiency
Frequency of Turner’s Syndrome:
1/8000 live female births
Intelligence in Turner’s Syndrome?
Normal intelligence
What are the key features in Turner’s Syndrome?
Stature below 5 feet
Infertile
Lymph stasis in infants of hand foot and neck
Bilateral webbing of the neck
Complete loss of oocytes by 2 years old
Preductal coarctation (BP high in upper extremity low in lower extremity)
What is Klinefelter Syndrome?
47 XXY Male (can be XXXY, XXY, XYY)
What is Turner’s syndrome?
45 XO
What does a Klinefelter patient present as?
Male with completely female features
What is the histology of the testis in Klinefelter patients?
Pink
Hyaline
Collagenous ghosts
Atrophic tubules
What happens to seminiferous tubules in Klinefelter?
They do not form leading to decreased inhibin and increased FSH
What occurs to sex hormones in Klinefelter?
No Leydig cells to produce Testosterone so GnRH will increase but only effect is an increase in estradiol production
Frequency of Klinefelter:
1/660 Male births
What occurs in testosterone insensitivity?
Can be one of multiple reasons there is a dysfunction in androgen receptors
What is elevated in testosterone insensitivity?
Testosterone and LH
What is absent in testosterone insensitivity?
Mesonephric ducts
DHT
Prostate and external genitalia
How is testosterone insensitivity differentiated from 17 alpha-hydroxylase deficiency?
Absence of hypertension
Why are there no ovaries in testosterone insensitivity?
Because the testis are present therefore are the Sertoli cells to secrete AMH causing destruction of Wolffian ducts
Why do testosterone insensitive males have female and not male external genitalia?
No DHT to form male secondary/external genitals
Where are testis located in testosterone insensitive females?
In the Labia majora
Why do the testis develop in testosterone insensitive females?
There is a Y chromosome to encode for them and not the default ovaries
What does 5a-reducatase deficiency cause in males?
No DHT formation from Testosterone
What is 5a-reductase deficiency genitalia like?
Testis with female genitalia
What is different about 5a-reductase deficiency and testosterone insensitivity?
5a-reductase deficiency you have Wolffian duct since you have AR for testosterone to bind and activate Sertoli cells to release AMH and you develop a rudimentary penis when puberty hits bc the increase in testosterone
What can cause female pseudohermaphroditism congenital adrenal hyperplasia?
21a-hydroxylase deficiency
11b-hydroxylase deficiency
Key signs in 21a-hydroxylase deficiency?
Water wasting
Hypotension
Hyponatremia
Hyperkalemia
Key signs in 11b-hydroxylase deficiency?
Water retention
Edema
Hypertension
Hypernatremia
Why does congenital adrenal hyperplasia occur?
A deficiency in the enzymes forming mineralocorticoids or glucocorticoids will cause a shunting to the formation of androgens causing hyperplasia of the zona reticularis
