Consider the below scenario to answer questions 38-41.
In a certain population, there's an autosomal recessive disorder called
Phenylketonuria (PKU), characterized by the inability to metabolize the amino acid
phenylalanine. The mutation responsible for PKU occurs in the gene PAH. While PKU
is rare in the general population, it's relatively common in certain ethnic groups, such
as those with Northern European ancestry. A 28-year-old woman named Emily,
whose grandfather and maternal uncle has PKU, is concerned about the likelihood
of having an affected child with her 30-year-old husband, Jack. Jack's family history
is negative for PKU.
