So for some people maybe non-celiac gluten sensitivity isn't a protein...but a carbohydrate?
http://www.npr.org/blogs/thesalt/2014/05/22/314287321/sensitive-to-gluten-a-carb-in-wheat-may-be-the-real-culprit
"That carbohydrate, called fructan, is a member of a group of carbs that gastroenterologists say is irritating the guts of a lot of people, causing gas, diarrhea, distention and other uncomfortable symptoms. Altogether, these carbs are called fermentable oligo-di-monosaccharides and polyols, or the cumbersome acronym FODMAPs.
If you're someone with a sensitive stomach and you've never heard of FODMAPs, listen up. In addition to fructan in wheat (and garlic and artichokes), FODMAPs include fructose (found in some fruit), lactose (found in some dairy products) and galactans (found in some legumes).
While most people can digest FODMAPs with no problem, for many with chronic gut disorders like irritable bowel syndrome, they're poorly absorbed by the small intestine and then fermented by bacteria to produce gas, which leads to those unpleasant symptoms. IBS affects up to 20 percent of Americans."
This report suggests that up to 70% of people see improvement in their IBS symptoms when they try the low-FODMAP diet. My symptoms that are the worst from gluten are not the IBS symptoms, but FODMAP might be an interesting diet choice for other people and for other problems.