What are the causes of celiac disease (gluten allergy)?

A reaction to gluten: Celiac disease (gluten allergy) occurs in a person who may have a genetic tendency to react abnormally to gluten (a protein in wheat, barley, and rye). Something causes his immune system to over-react to gluten. Later, when he eats foods containing gluten, his immune system reacts with the intestine that is digesting the gluten, thus causing intestinal problems and abnormal digestion.

Gluten sensitivity: There are hereditary factors involved, but in general, celiac disease is a sensitivity to gluten. Gluten is found in wheat, oats, rye and barley.