Of 1974 cases included in this study, 1002 underwent an intestinal biopsy and in 542 at least Marsh type 2 mucosal damage was found: 511 (94%) were classified as CCD, because of positivity of tTG or EMA, 31 (6%) were classified as UCD because of negativity of both tTG and EMA. The gene discussed is TGM2; the disease is urea cycle disorder.