The cut-off value of anti-tTG antibody titer levels for diagnosing Celiac disease using receiver operating characteristics (ROC) curve in predicting Marsh greater than two at histology was observed to be 84.6 U/ml with sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 91.7%, 68.4%, 94.2%, and 59%, respectively. The gene discussed is TGM2; the disease is celiac disease.