Review session slides

Question 1

signs of AR

Answer 1

• M and F equally effected
• NOT in every generation
• affected child of unaffected parents

Question 2

signs of AD

Answer 2

• M and F equally effected
• present in every generation
• variable expressivity and reduced penetrance
• affected parent and child

Question 3

X linked R

Answer 3

-males more likely to be affected
-no male to male transmission
-carrier females unlikely to show symptoms
-

Question 4

X linked D

Answer 4

• sometimes male lethality
• no male to male transmission
• females do show symptoms

Question 5

x chromosome
-why it happens
-which chromosome
-preferential inactivation
-

Answer 5

• equalizing x chromosome expression for males and females
• random which x gets inactivated
• if one x is damaged, it is preferentially inactivated

Question 6

heteroplasmy and threshold concepts

Answer 6

• if the progenitor cell has some healthy adn some mutated mitochondria, it is completely random how they will be distributed during mitosis
• could result in one cell having all mutated and the other having all healthy or somewhere in between
• heteroplasmy = some mutant and some normal mitochondria in one cell
• a certain threshold of mutated mitochondria must be reached before there is an observable phenotype

Question 7

anticipation

Answer 7

-disorders that are caused by a propogation and elongation of tandem repeats often get worse with each subsequent generation due to an increase in the number of repeats getting longer

Question 8

two ways in which to get prader willi or angelmans

Answer 8

• uniparental disomy: due to nondisjunction, an egg has two homologous chromosome and when the sperm introduced, the paternal homologous chromosome it destroyed leaving two maternal chromosome 15’s
• genomic imprinting: the pternal chromosome 15 is imprinted (methylated) and this gene needs to come specifically from the father

Question 9

why would UPD disorders not run in fmailies?

Answer 9

because genomic imprinting gets reset

Question 10

liability

Answer 10

collectively describes all genetic and environmental factors that contribute to the development of a disorder
-there is a threshold of liability that must be reached to develop a phenotype

Question 11

malformation

Answer 11

• due to an intrinsicly abnormal problem with formation, growth or differentiation
• cleft palate, syndactyly, reenal agenesis

Question 12

deformation

Answer 12

• normally formed structure tpushed out by mechanical/external forces that mold a fetus over a period of time
• club foot,
• congenital hip dysplasia

Question 13

disruption

Answer 13

• changes in morphology of already formed tissue or structures due to destructive processes
• amniotic banding

Question 14

dysplasia

Answer 14

• abnormal cellular organization, intrinsic to the cellular architecture of a tissue
• achondroplasia,