Is there any genetic component to the top of your differentials?

A three-month-old baby boy comes into your clinic with the main complaint that he frequently vomits after eating. He often has a swollen upper belly after feeding and acts fussy all the time. The vomiting has become more frequent this past week and he is beginning to lose weight.

Write three (3) differential diagnoses at this time?
Is there any genetic component to the top of your differentials?
What tests would you order?