Genetic development: birth defects Flashcards Preview

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Flashcards in Genetic development: birth defects Deck (23):
1

What are the two classes of transcription factors?

Unspecific and specific

2

What gene is responsible for the development of the anterior/posterior axis?

HOX genes

3

How do cells signal their relative position in an embryo?

cell-cell contact
secretion of morphogens

4

What are morphogens? How does it affect development?

Secretions of cells that signals their position, leading to a gradient in the embryo. Cells change their development based on [mophogens]

5

What is the sonic hedgehog protein? How does it influence development?

secreted from the notocord and develops a gradient. Helps organize the different cells in the brain and spinal cord

6

A mutation in shh leads to what?

Midline defects

7

What chemical must the Shh protein interact with for function?

Cholesterol

8

What is SLOS (Smith-Lemli-Opitz syndrome)?

Severe congenital malformations due to the impairment of Shh by a lack of cholesterol

9

What does cell changing shape in development consist of?

Rearranging the cytoskeleton and polarizing the secretions of proteins to apical or basal surface

10

What is polycystic disease (where cysts develop on the kidneys) the result of?

An overgrowth of a kidney duct due to a lack of polycstin 1 or 2. this disrupts cell's ability to sense flow of fluid to stop and change development

11

Why is migration important in embryonic development?

CNS cells need to migrate from the neural tube in waves

12

What is lissencephaly?

Mutation or deletion of the LIS1 gene that interferes with the orderly migration of CNS cells away from the neural tube. Severe MR.

13

Apoptosis is a key feature in the development of which organs?

Heart
separation of digits
perforation of anal and choanal membranes
connection b/t vagina and uterus
immune system

14

How do autoimmune diseases develop?

failure of lymphocyte that react to the body to undergo apoptosis in development

15

What is hermaphroditism?

When pt has both testes and ovarian tissues

16

What is pseudohermaphroditism?

Pts have either testes or ovaries, but phenotype does not match their sex

17

What is the critical region on the Y chromosome for male development?

Sex-determining region of Y (SRY)

18

What happens if the SRY region is destroyed?

female develops with a Y chromosome

19

What happens if the SRY region is translocated to an X chromosome?

Male develops with XX chromosomes

20

What is female pseudohermaphroditism?

females with normal ovaries but ambiguous or male genitalia

21

Female pseudohermaphorditism is caused by Congenital adrenal hyperplasia (CAH). What is this?

Caused by a defect in a 21-hydroxylase involved in cortisol synthesis. Cortisol shunted to androgen synthesis

22

What are the three possible causes of male pseudohermaphroditism?

a defect in testes during development
problem in androgen biosynthesis
Deficiency in androgen receptor production

23

What is the tumor progenitor cell model?

Abnormalities in stem cells leads to a pool of cells that are incompletely differentiated. Benign, but can mutate, leading to CA.