What is Zollinger-Ellison syndrome ?
It is defined as pancreas and small intestine tumors that produces high level of gastrin causes peptic ulcer. It is also known as gastrinomas.

Symptoms
Constant loosing of weight
loose stools
Nausea
Vomitings
Abdominal pain
Acid reflux
burning and heartburn
Digestive tract bleeding
Complete loss of appetite

Causes
Its reason is still unknown. It could be genetic, can passes from old ancestors to siblings.