In the H. pylori-positive children, a negative correlation was observed between MCV (r = −0.26; p = 0.01) and MCH (r = −0.27; p = 0.01) values and the degree of antral chronic inflammation; as well as between MCH and the degree of corpus chronic inflammation (r = −0.29, p = 0.008) and active inflammation (r = −0.27, p = 0.002). The gene discussed is PMCH; the disease is inflammation.