--there is the controversy now in gluten/celiac circles as to whether thaat conditon can manifest in those who have other than the human leukocyte antigen (HLA) DQ2 or DQ8 genetic subtype. (There's some evidence that some people who tend more towards neurological manifestations of gluten sensitivity, such as ataxia or neuropathy, are more likely to be subtype DQ1; apparently there are even a few biopsy-proven celiacs with that type, according to some of the work of Dr. Hadjivassiliou and colleagues).

I know Liza Jane has some knowledge of mitchondrial disorders--perhaps she'll chime in.

It is a very interesting area--made all the more confusing by the idea of genetic predisposition then being expressed (or not expressed) by environmental factors turning certian genes on or off. Much of what we know now will certainly go through revision and reparadigmization over the next decades.