You are a doctor who specializes in genetic diseases. A married couple comes to see you for genetic ...

Since the woman has the disease, she must be homozygous recessive for the defective autosomal gene. If her husband is not a carrier, all their children will be heterozygous carriers of the disease. However, since the man and woman are closely related, there is a high probability that the man is a carrier of the PKU gene. If he is a carrier, there is a 50 chance that any of their children will have the disease. You would perform a detailed pedigree analysis for the couple to better determine the probability that the husband carries the recessive allele.