Cardiology>>>>>Genetics, Lipids And Tumours
Question 3#

You are seeing a 28-year-old man in clinic. He has long QT sydrome due to a mutation in the KCNH2 gene. He has two sons and a daughter. One son and his daughter have been tested and found to have the same mutation as him.

What is the chance that his younger son also has this mutation?

A) 0
B) 1/3
C) 1/2
D) 2/3
E) 1

Correct Answer is C

Comment:

He is affected with a dominantly inherited condition. Therefore there is 1 in 2 chance for each child.