A Woman and Her Husband Have a Child Affected with Maple

A woman and her husband have a child affected with maple syrup urine disease (MSUD) . The woman subsequently has an affair and becomes pregnant, but the father of this baby cannot be contacted for genetic testing. What information would be used to determine the risk of MSUD in the second child?

A) Mutation rate for the MSUD genes
B) Carrier frequency for MSUD mutations in the general population
C) Carrier frequency for MSUD mutations in the appropriate ethnic population
D) The risk can be calculated based on the mother's genotype alone
E) The risk cannot be calculated with reasonable accuracy