Mirrasi

My 12 year old has had GI issues since birth. He's had blood tests and 2-3 years ago had a colonoscopy. All tests and biopsies came back negative for Celiac's. He had inflammation and pictures where all bumpy but we didn't really get any answers. Is it possible he could have Celiac's and have had a false negative on the biopsy. He has soooooo many symptoms...