The patient is a 22 year old man who is found on routine exam to have a serum calcium of 11.4 mg/dL. His vital signs and physical examination are normal. On further questioning he states that his father and paternal uncle have had neck surgery and and his father has also had a tumor in his pancreas. His brother has had surgery of his pituitary.

1. What is your differential diagnosis?

2. What testing would like to do?