The exact specific cause of Celiac Disease not known, yet. The only thing that is known for sure is that you have to have specific genes, have been ingesting gluten, and have had something trigger the disease. You have to have all three factors to develop Celiac Disease.
If you are going to develop Celiac Disease, you must have certain genes: either HLA-DQ2 or HLA-DQ8. These are actually the names of molecules on cells that are used as the names of the genes. Celiac Disease cannot develop unless ones of these genes is present, but having one of these genes does not mean that developing Celiac Disease is inevitable. But if you do not have one of these genes, you won’t develop Celiac Disease.
I guess we all know that ingesting gluten means eating gluten.
While the exact trigger is not yet known, there are several things that are common triggers. This includes pregnancy, physical injury/accident, emotional trauma, illness, or surgery.