Multifactorial and Polygenic Inheritance Flashcards
How can you tell if something is multifactorial?
not 100% in monozygotic twins
What is polygenic?
genetic load determines risk (i.e more than one gene)
Diabetes type I and II, cleft lip, pyloric stenosis, NTD are all what?
polygenic/multifactorial
HOw can you prevent complications from diabetes?
blood glucose and lipid levels are kept in check
Why has diabetes increased?
environmental factors/ obesity
Is susceptibility to obesity and diabetes genetic?
yes
HOw can you know that obesity and diabetes has genetic linkage?
cuz mono and dizygotic twins dont have the same ratio of obesity.
If the concordance rate for both monozygotic and dizygotic twins is 40x higher than
the population risk, is the risk of disease predominantly genetic or environmental?
environmental, cuz if mono and di have the same concordance rate, then it is influenced by environment completely
How do you get calculate the heritability caused by genes?
Heritability (concordance rate)= (monozygotic twins–dizogotic) X 2.
In what type of diabetes do you have normal glycemic control and then it messes up?
type I
In polygenic/multifactorial disorders, although clearly genetic, risk cannot be calculated based on (blank)
degree of relationship i.e. probability of shared genes
In polygenic/multifactorial disorders, how are recurrence risks determined?
empirical data
In polygenic/multifactorial disorders, recurrence risk will change from population to population and from family to family due to differences in (blank)
genetic load
When dealing with polygenic/multifactorial inheritence, how can you know that this is what is occuring just by looking at recurrence risk?
because the relationship between distant family members (coefficient of relationship) with an affected indivdiual doesnt correlated correctly. In fact, risk is less than predicted
(blank) increases if more than one family member affected.
recurrence
Recurrence risk is higher if proband is of the less commonly affected (blank)
sex
In multifactorial/polygenic inheritance, if you are affected, what is the liklihood that your aunt is affected?
significantly lower than the coefficient of relationship would suggest. Like 7% or something
(blank) trait is when the phenotype distributes across a more or less
Gaussian (normal) distribution across a population.
quantitative trait
What does this describe:
disease does not have a normal distribution, but is the result of a continuous underlying liability. If threshold is exceeded, then disease results.
threshold of liability
In threshold liability, the disease doesnt have a normal (blank). HOwever, the genetic susceptibility does.
gaussian distribution
(blank) can alter thresholds.
sex
If you have a multifactorial/polygenic disease that must reach a threshold and it is seen more often in males, who would be at greater risk siblings of an affected female or of an affected male?
female
