Celiac without HLA genes

A friend of mine got diagnosed with Collagenous Colits about 5 years ago. Also diagnosed with soy allergy at the Enterolab about the same time.
He recently did an HLA and it was negative.
He also did Endomysial Antibody IgA, Gliadin Peptide IgG, Gliadin Peptide IgA and Tissue Transglutaminase IgA - all negative.

Are there any other blood tests?

I read on the Celiac Center page from the Chicago University (http://www.cureceliacdisease.org/archives/faq/can-you-have-celiac-disease-without-having-the-genes-for-it) that Dr Guandalini says that you can't have Celiac without the gene.

According to him if you don’t have the genetic markets for celiac that you don’t have it, and there’s never been any documented cases of anybody having celiac without the genetic markers.

Does anybody know somebody with Celiac who doesn't have this HLA gene? Or can you have something that has the same symptoms as Celiac, but doesn't have the gene - what would it be called and how would you test for it?

Thank you