What do SRY and SOX9 do?
produce AMH and cause regression of the paramesonephric duct
What happens during the 4th week of conception?
the germ cells form in the wall of the yolk sac
The most common cause of ambuiguous genitalia in a female is _____.
What is sex chromosome aneuploidy?
disorders that don't have the normal # of X or Y chromosomes
Mesonephric/Wolffian ducts result in _____ structures because of the ____ and _____ genes.
male; SRY; SOX9
What are the signs and symptoms for Triple X Syndrome?
females with tall stature, learning disabilities, delayed speech and motor milestones, seizures, kidney problems
What is the incidence rate for Triple X Syndrome?
1:1000 newborn females
Which chromosome carries the AR gene?
What is the incidence rate for Jacobs Syndrome?
1:1000 newborn males
What is the incidence rate of Kleinfelter Syndrome?
1:500 newborn males
What is the karyotype of Kleinfelter Syndrome?
What happens during the 8th week of conception in a male?
Leydig cells make T; Sertoli cells make AMH; sex cords differentiate
What happens during the 5th week of conception?
the coelomic epi becomes the genital ridge
Half of a female's cells express the _____ inherited X, while the other half express the _____ inherited X chromosome.
Females are ______ for their X chromosome.
X chromosome inactivation wont occur without ____.
WNT4 protein _________.
differentiates the ovary
What happens during the 7th week of conception?
the genital ridge begins to differentiate
Under the influence of ________, the paramesonephric ducts become the _______.
Estrogen, uterus, cervix, broad ligament, Fallopian tube, and upper 1/3 of the vagina
When is X chromosome inactivation skewed?
when females have X-linked recessive conditions, the normal gene is sometimes turned off, allowing the female to express the phenotype
x chromosome inactivation
one x chromosome is randomly turned off
How would you test a child with disorder of sexual differentiation?
1) FISH for X and Y 2) check hormone levels 3) check for mutations
What is the result of 5-alpha reductase deficiency?
decreased ability of the body to convert T to dihydrotestosterone
What does FGF9 do?
differentiates the testes
What are the signs and symptoms of Kleinfelter Syndrome?
learning disabilities, tall stature, small testicles, reduced body hair, infertile, hypospadias, gynocomastia
What does SF1/NR5A1 do?
stimulates differentiation of Sertoli and Leydig cells
The X chromosome has about _____ genes.
Ectopic presence of SRY gene in 46XX results in ____.
a phenotypically normal male
Where is XIST located? What expresses it?
On the X chromosome; the inactive X
When does X chromosome inactivation occur?
in week 1 of embryogenesis
What is the karyotype for 5-alpha reductase deficiency?
What is primary sex determination?
determination of the gonads
Both male and female external genitalia originate from the _____.
What happens during the 6th week of conception?
the primordial germ cells migrate to the dorsal mesentery and enter the gonad; sex cords form
What is the karyotype for Androgen Insensitivity Syndrome?
What is the karyotype for Triple X Syndrome?
What is the phenotype of 5-alpha reductase deficiency?
at birth, undervirilized genitalia but this improves at puberty
When does nonrandom X chromosome inactivation occur?
when there is a structurally abnormal X chromosome- more of the normal X is turned on
What is the karyotype for Jacobs Syndrome?
21-hydroxylase deficient patients have a karyotype of _____.
What is secondary sex determination?
the gonads determine the 2a sex characteristics
What happens during the 8th week of conception in a female?
sex cords dissociate; Medullary cords regress; cortical cords are formed to become follicular cells
The mesonephric duct, because of T, will become the ____, _____, and _____.
epidymis, seminal vesicles, vas deferens
What is X chromosome aneuploidy?
no matter how many X chromosomes are present, all but one are always inactivated
Gonad determination Is ______.
There are about ____ genes on the Y chromosome.
Denys-Drash and Frasier Syndrome pts phenotypically _____.
have sex reversal and kidney issues
the inactivated X chromosome clumped up
Which gene inactivates the X chromosome?
What complicates 21-hydroxylase deficient patients?
salt wasting- decreased Na and Cl with increased K
What prevents the inactivated X chromosome from being expressed?
methylation of the promoter region
Mutation of the AR gene causes what phenotypes?
mild under-virilization to full sex reversal
Mutations of SRY in a 46XY individual results in _____.
reduced or absent production of anti-Mullerian hormone and under virilization of the male
What are the 2 pairs of genital ducts in both males and females at 6 weeks?
Mesonephric (Wolffian) and Paramesonephric (Mullerian)
Denys-Drash and Frasier Syndrome is due to a mutation in ____.
What are the signs and symptoms for Jacobs Syndrome?
learning disabilities, speech delays, developmental delays, behavioral issues, autisms, tall stature
The paramesonephric or Mullerian ducts result in ____ structures because ___ and ____ are not present.
female; SRY; SOX9