lecture 43 Flashcards
The majority of human genetic disorders are……
multifactorial
what is meant by multifactorial?
disease can be affected by genetics and environment
What is genetic liability?
This model try’s to explain the populations genetic and environment risk of certain diseases
What is the familial relative risk?
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
What is the relative risk ratio?
prevalence of the disease in relatives over the prevalence in the general population.
what does a high and low heritability risk mean?
high = more genetic
low = more environmental
liability threshold model explains what?
- ) Risk of recurrence is higher in relatives of severely affected individuals
- Recurrence risk is high in close relatives and
decreases rapidly in more distant relations - Greater risk if more than one close relative is
affected - sex-based traits
What is the threshold of pyloric stenosis in both genders?
the threshold is much lower in mans compared to females
What tools can be used to determine the genetic component of a disease?
- population and migration studies
- family studies
- twin studies
- adoption studies
- association studies
What is concordance?
means that both twins have the same disease
what is discordance?
means that one twin has the disease and not the other
what are the limitations of twin studies?
- may underestimate heritability
- MZ’s do have some different genes
- different environmental exposures
- ascertainment bias
