lecture 43

Question 1

The majority of human genetic disorders are……

Answer 1

multifactorial

Question 2

what is meant by multifactorial?

Answer 2

disease can be affected by genetics and environment

Question 3

What is genetic liability?

Answer 3

This model try’s to explain the populations genetic and environment risk of certain diseases

Question 4

What is the familial relative risk?

Answer 4

The more closely related you are to someone with a mulifactorial disorder, the more likely you are to have similar alleles

but that risk drops by half for every degree of distance from that affected person

Question 5

What is the relative risk ratio?

Answer 5

prevalence of the disease in relatives over the prevalence in the general population.

Question 6

what does a high and low heritability risk mean?

Answer 6

high = more genetic

low = more environmental

Question 7

liability threshold model explains what?

Answer 7

1. ) Risk of recurrence is higher in relatives of severely affected individuals
2. Recurrence risk is high in close relatives and
   decreases rapidly in more distant relations
3. Greater risk if more than one close relative is
   affected
4. sex-based traits

Question 8

What is the threshold of pyloric stenosis in both genders?

Answer 8

the threshold is much lower in mans compared to females

Question 9

What tools can be used to determine the genetic component of a disease?

Answer 9

1. population and migration studies
2. family studies
3. twin studies
4. adoption studies
5. association studies

Question 10

What is concordance?

Answer 10

means that both twins have the same disease

Question 11

what is discordance?

Answer 11

means that one twin has the disease and not the other

Question 12

what are the limitations of twin studies?

Answer 12

1. may underestimate heritability
2. MZ’s do have some different genes
3. different environmental exposures
4. ascertainment bias