Genetic Probability and Risk Assessment

Dr. Bruce Korf discusses genetic risk assessment, focusing on Mendelian inheritance and Bayes' Theorem. The lecture covers autosomal recessive, dominant, and X-linked recessive inheritance, as well as incomplete and age-dependent penetrance. Practical examples illustrate how to calculate genetic risks, emphasizing the importance of Bayes' Theorem in refining these calculations. The session concludes with a call for feedback to improve the content.

What is the primary focus of genetic risk assessment as introduced by Dr. Bruce Korf?

• Assessing risks through psychological evaluation

• Calculating risks based on environmental factors

• Understanding genetic risks through Mendelian inheritance and Bayes' Theorem

• Evaluating risks based on lifestyle choices

In autosomal recessive inheritance, what is the probability of two carrier parents having an affected child?

• 1 in 2

• 1 in 3

• 1 in 5

• 1 in 4

If a woman has a sibling with an autosomal recessive trait, what is her estimated risk of being a carrier?

• 2/3

• 3/4

• 1/3

• 1/4

In autosomal dominant inheritance, what is the chance of an affected individual passing the trait to their offspring?

• 100%

• 75%

• 50%

• 25%

For an x-linked recessive trait, what is the probability of a carrier female having an affected male child?

• 50%

• 100%

• 0%

• 25%

What does incomplete penetrance mean in genetic terms?

• The trait is always expressed when the gene is present

• The trait is never expressed when the gene is present

• The trait is expressed only in some individuals with the gene

• The trait is expressed in all individuals regardless of the gene

How does age-dependent penetrance affect the expression of genetic traits?

• The probability of expression increases with age

• The probability of expression remains constant with age

• Age has no effect on the expression of genetic traits

• The probability of expression decreases with age

In a scenario using Bayes' Theorem, what is the prior probability of a woman being a carrier if her father is affected?

• 1.0

• 0.75

• 0.5

• 0.25

What is the joint probability of a woman being a carrier and having two healthy sons in an x-linked recessive pedigree?

• 0.75

• 0.125

• 0.25

• 0.5

What is the posterior probability of a woman not being a carrier if she has two healthy sons?

• 0.2

• 0.4

• 0.6

• 0.8