Subjects with any history of organic GI diseases, i.e., celiac disease, Crohn ́s disease, lactose intolerance, reflux, ulcer, or ulcerative colitis (n = 54), had the same zonulin levels as those without (53.6 (47.9–63.4) ng/mL vs. 53.6 (44.0–62.7) ng/mL; p = 0.566), as was also true for those with any functional GI symptoms, i.e., functional dyspepsia or IBS (n = 61), compared with those without (52.7 (46.2–59.7) ng/mL vs. 53.7 (44.2–63.7) ng/mL; p = 0.530). The gene discussed is HP; the disease is irritable bowel syndrome.