Question

A normal men and women who have phenylketonuria(affected)child,which is autosomal recessive trait.The woman becomes pregnant again and carrying monozygotic twins.What is the probability of phenylketonuria in twins​

Answer 1

Since the first child is affected the mother is the carrier of the disease therefore there is chances for affected, carrier and normal children and even twins with the same constitution

Answer 2

Explanation:

Normal men and women who have phenylketonuria gene, but does not show the disease, had passed to the child, which is an autosomal recessive trait as an inheritance pattern.

The monozygotic conditions result in twins from one egg and one sperm, which results in two embryos. Hence the one child may be a carrier of PKU genes which may be active and symptoms and the other may just carry the gene but no symptoms as their parents.