Birth Defects Flashcards
What are the 2 classes of transcription factors?
unspecific, general: CREB:
specific: HOX
What would happen to if HOXA13 and HOXD13 were mutated?
disturb the development of the fingers and toes; as late hox genes are important for the development of the distal pole
What is Shh secreted from?
notochord
What is the role of Shh (2 things)
- brain/spinal cord
2. posterior limb development
If there is a mutation in Shh, what does this lead to in general?
Midline defects (failure to develop the midface and the forebrain)
What is holoprosencephaly?
Caused by a mutation in Shh; midline defect
What is important for Shh protein synthesis? If this isnt around, what disease can result?
cholesterol
Smith Lemli Opitz Syndrome: cause multiple severe congenital malformations
During development, cells must respond to environmental clues by changing shape and polarity. Explain this process in the kidney.
- kidney cells need to develop an apical and basal side
2. they do this by detecting a stream, which will cause cells to stop proliferating, causing correct polarization.
What happens if polycystin 1 or 2 are mutated? what disease does this cause?
renders a cell incapable of sensing flow; no polarity developed
leads to polycystic kidney disease
Explain the process of cell migration in the developing CNS.
- neuronal stem cells of neural tube –> neuronal precursor cells
- migrate outward from the ventricle along a scaffold of glial cells (occurs in waves)
What occurs in a mutation of the LIS1 gene?
lissencephalpy; smooth brain; cells cant migrate
Apoptosis is especially important for what 5 things?
- heart
- digits
- anal
- uterus and vagina connection
- immune system
True hermaphroditism? vs pseudohermaphroditism?
true: have both testes and ovaries
psuedo: patients pheno does not equal geno
What are 2 reasons for chromosomal aberrations involving SRY leading to sex reversal disorders?
- if sry is deleted on the Y chorm, the embryo develops into a female of XY
- if sry is translocated to the X-chrom, the embryo develops into a male with an XX
Adrenal hyperplasia is the most common cause for what?
female pseudohermaphroditism: caused by a defect in cortisol biosynthesis, so everythign shunted to androgen pathway