Answer to Question #166059 in Genetics for Kristiina Hyttinen

Question

4. You are advising prospective parents on possible outcomes if they have children. Both are carriers of the gene for cystic fibrosis. If they have 2 children, what are the probabilities that a) one will have the disease? b) both will have the disease? C) both will be disease free but both will be carriers? d) both will be disease free, and neither will be a carrier?

Answer 1

a) One will have the disease.

It is an autosomal recessive disorder. In the affected child, both copies of the gene are mutated.