Genetic development: birth defects

Question 1

What are the two classes of transcription factors?

Answer 1

Unspecific and specific

Question 2

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

Answer 2

HOX genes

Question 3

How do cells signal their relative position in an embryo?

Answer 3

cell-cell contact

secretion of morphogens

Question 4

What are morphogens? How does it affect development?

Answer 4

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

Question 5

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

Answer 5

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

Question 6

A mutation in shh leads to what?

Answer 6

Midline defects

Question 7

What chemical must the Shh protein interact with for function?

Answer 7

Cholesterol

Question 8

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

Answer 8

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

Question 9

What does cell changing shape in development consist of?

Answer 9

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

Question 10

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

Answer 10

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

Question 11

Why is migration important in embryonic development?

Answer 11

CNS cells need to migrate from the neural tube in waves

Question 12

What is lissencephaly?

Answer 12

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

Question 13

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

Answer 13

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

Question 14

How do autoimmune diseases develop?

Answer 14

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

Question 15

What is hermaphroditism?

Answer 15

When pt has both testes and ovarian tissues

Question 16

What is pseudohermaphroditism?

Answer 16

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

Question 17

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

Answer 17

Sex-determining region of Y (SRY)

Question 18

What happens if the SRY region is destroyed?

Answer 18

female develops with a Y chromosome

Question 19

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

Answer 19

Male develops with XX chromosomes

Question 20

What is female pseudohermaphroditism?

Answer 20

females with normal ovaries but ambiguous or male genitalia

Question 21

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

Answer 21

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

Question 22

What are the three possible causes of male pseudohermaphroditism?

Answer 22

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

Question 23

What is the tumor progenitor cell model?

Answer 23

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