There seems to be a major gap in the Gluten theory that is puzzling me.

There does not appear to be any reason why somebody would be affected with one medical disorder rather than another.

Even if there are proteins in the body that have similar structures to the two proteins in gluten, and that each of these proteins are related to a different medical disorder, it still doesn't explain why only one of these would be affected in one individual and another would be affected in another individual.