Sex Chromosomes and Disorders Flashcards Preview

M2M Unit II > Sex Chromosomes and Disorders > Flashcards

Flashcards in Sex Chromosomes and Disorders Deck (57):
1

What do SRY and SOX9 do?

produce AMH and cause regression of the paramesonephric duct

2

What happens during the 4th week of conception?

the germ cells form in the wall of the yolk sac

2

The most common cause of ambuiguous genitalia in a female is _____.

21-hydroxylase deficiency

3

What is sex chromosome aneuploidy?

disorders that don't have the normal # of X or Y chromosomes

3

Mesonephric/Wolffian ducts result in _____ structures because of the ____ and _____ genes.

male; SRY; SOX9

4

What are the signs and symptoms for Triple X Syndrome?

females with tall stature, learning disabilities, delayed speech and motor milestones, seizures, kidney problems

4

What is the incidence rate for Triple X Syndrome?

1:1000 newborn females

4

Which chromosome carries the AR gene?

X

5

What is the incidence rate for Jacobs Syndrome?

1:1000 newborn males

6

What is the incidence rate of Kleinfelter Syndrome?

1:500 newborn males

7

What is the karyotype of Kleinfelter Syndrome?

47XXY

7

What happens during the 8th week of conception in a male?

Leydig cells make T; Sertoli cells make AMH; sex cords differentiate

8

What happens during the 5th week of conception?

the coelomic epi becomes the genital ridge

9

Half of a female's cells express the _____ inherited X, while the other half express the _____ inherited X chromosome.

maternally; paternally

10

Females are ______ for their X chromosome.

mosaic

11

X chromosome inactivation wont occur without ____.

XIST

12

WNT4 protein _________.

differentiates the ovary

13

What happens during the 7th week of conception?

the genital ridge begins to differentiate

13

Under the influence of ________, the paramesonephric ducts become the _______.

Estrogen, uterus, cervix, broad ligament, Fallopian tube, and upper 1/3 of the vagina

14

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

15

x chromosome inactivation

one x chromosome is randomly turned off

16

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

16

What is the result of 5-alpha reductase deficiency?

decreased ability of the body to convert T to dihydrotestosterone

17

What does FGF9 do?

differentiates the testes

18

What are the signs and symptoms of Kleinfelter Syndrome?

learning disabilities, tall stature, small testicles, reduced body hair, infertile, hypospadias, gynocomastia

19

What does SF1/NR5A1 do?

stimulates differentiation of Sertoli and Leydig cells

20

The X chromosome has about _____ genes.

1000

20

Ectopic presence of SRY gene in 46XX results in ____.

a phenotypically normal male

22

Where is XIST located? What expresses it?

On the X chromosome; the inactive X

23

When does X chromosome inactivation occur?

in week 1 of embryogenesis

24

What is the karyotype for 5-alpha reductase deficiency?

46XY

26

What is primary sex determination?

determination of the gonads

27

Both male and female external genitalia originate from the _____.

urogenital sinus

28

What happens during the 6th week of conception?

the primordial germ cells migrate to the dorsal mesentery and enter the gonad; sex cords form

29

What is the karyotype for Androgen Insensitivity Syndrome?

46XY

31

What is the karyotype for Triple X Syndrome?

47XXX

32

What is the phenotype of 5-alpha reductase deficiency?

at birth, undervirilized genitalia but this improves at puberty

33

When does nonrandom X chromosome inactivation occur?

when there is a structurally abnormal X chromosome- more of the normal X is turned on

34

What is the karyotype for Jacobs Syndrome?

47XYY

35

21-hydroxylase deficient patients have a karyotype of _____.

46XX

36

What is secondary sex determination?

the gonads determine the 2a sex characteristics

37

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

38

The mesonephric duct, because of T, will become the ____, _____, and _____.

epidymis, seminal vesicles, vas deferens

40

What is X chromosome aneuploidy?

no matter how many X chromosomes are present, all but one are always inactivated

41

Gonad determination Is ______.

chromosomal

43

There are about ____ genes on the Y chromosome.

200

44

Denys-Drash and Frasier Syndrome pts phenotypically _____.

have sex reversal and kidney issues

45

Barr body

the inactivated X chromosome clumped up

46

Which gene inactivates the X chromosome?

XIST

47

What complicates 21-hydroxylase deficient patients?

salt wasting- decreased Na and Cl with increased K

49

What prevents the inactivated X chromosome from being expressed?

methylation of the promoter region

52

Mutation of the AR gene causes what phenotypes?

mild under-virilization to full sex reversal

53

Mutations of SRY in a 46XY individual results in _____.

reduced or absent production of anti-Mullerian hormone and under virilization of the male

54

What are the 2 pairs of genital ducts in both males and females at 6 weeks?

Mesonephric (Wolffian) and Paramesonephric (Mullerian)

55

Denys-Drash and Frasier Syndrome is due to a mutation in ____.

WT1 gene

56

What are the signs and symptoms for Jacobs Syndrome?

learning disabilities, speech delays, developmental delays, behavioral issues, autisms, tall stature

57

The paramesonephric or Mullerian ducts result in ____ structures because ___ and ____ are not present.

female; SRY; SOX9