Pyloric stenosis (PS) is a condition that is associated with hypertrophy (enlargement) of the muscle of the pyloris (outlet of the stomach). Infants with PS usually have severe vomiting beginning...

Pyloric stenosis (PS) is a condition that is associated with hypertrophy (enlargement) of the muscle of the pyloris (outlet of the stomach). Infants with PS usually have severe vomiting beginning around 2 to 6 months of life. PS is inherited in a multifactorial manner. It is more common in boys. A couple’s first born child (a male) was born with PS. It began when he was 2 months old. They come to you with questions about recurrence risk. Correct information to give them would include:

A. their recurrence risk would be lower if the first (affected) child had been a female. B. if the PS had been less severe (onset at 6 months), the recurrence risk would be higher. C. if there are any other affected relatives, the risk would be lower. D. the recurrence risk is about 20% to 25%. E. the inheritance of pyloric stenosis could also be called monogenic.