Genetic Counseling Video Lessons

Concept

# Problem: Consider the following pedigree of a rare autosomal recessive disease. Assume all people marrying into the pedigree do not carry the abnormal allele.a) If individuals A and B have a child, what is the probability that the child will have the disease?b) If the first child of C * D has the disease, what is the probability that their second child will have teh disease?

###### FREE Expert Solution

Individual A, having unaflicted parents but with an afflicted sibling tells us that her parents are both carriers of the disease, and she, while not being afflicted with the disease, still has a 66.7% chance of being a carrier. Remember that out of 4 possible outcomes, 2 will result in being a carrier of the disease, but the 4th outcome cannot happen as she is not affected. Thus, it is just 2 out of 3, which is 66.7%.

###### Problem Details

Consider the following pedigree of a rare autosomal recessive disease. Assume all people marrying into the pedigree do not carry the abnormal allele.

a) If individuals A and B have a child, what is the probability that the child will have the disease?

b) If the first child of C * D has the disease, what is the probability that their second child will have teh disease?