Question

If Jane has 3 healthy sons but just gets word that her maternal cousin Ashley has a son with DMD. Both Jane and Ashley would like to have more children. What would the pedigree look like? Who’s the carrier? Who’s affected? What’s the probability of the unborn children having DMD?

Answer 1

no information is given about Jane's husband, mother and father. however, the unborn son to have DMD, jane must be carrier (Xx). for the unborn daughter to have DMD, Jane should be carrier and her husband should be affected.

probability of jane's mother to be carrier is 1/2.

probability of jane to be carrier is 1/2.

jane's husband to be affected is 1/2.

children to would be 1/2 (if jane is carrier and her husband is affected)

unborn children to have DMD would be 1/2 x 1/2 x 1/2 x 1/2 = 1/16.