Sex Chromosomes and Disorders Flashcards Preview

M2M Unit II > Sex Chromosomes and Disorders > Flashcards

Flashcards in Sex Chromosomes and Disorders Deck (57)
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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