Question

"Chloe’s mother wants to have another child. However, she is concerned that a second child might also have CF, so she encourages Chloe’s stepfather to be tested. Tests reveal that he does NOT carry the CF gene. What is the chance that a second child born to Chloe’s mother and stepfather will have CF?"

Answer 1

Answer:

0%

Explanation:

The cystic fibrosis transmembrane conductance regulator (CFTR) protein is responsible for cystic fibrosis. It is transmitted in a autosomal recessive manner. This means that both parents must have the CF gene in order for the development of CF in the child.

Here, Chloe's father and mother both had the CF gene so Chloe developed CF. However, Chloe's stepfather does not have the CF gene hence a child with the step father will not have CF.