[The relationship between genetic polymorphism of CYP2C19 and the efficacy of Helicobacter pylori eradication therapy in children].

Objective: To investigate the relationship between genetic polymorphisms of cytochrome P450 2C19 (CYP2C19) and the efficacy of Helicobacter pylori (Hp) eradication therapy in children. Methods: The retrospective cohort study was conducted on 125 children with gastroscopy and positive rapid urease test (RUT) from September 2016 to December 2018 who presented to the Children's Hospital of Zhejiang University School of Medicine due to gastrointestinal symptoms including nausea, vomiting, abdominal pain, bloating, acid reflux, heartburn, chest pain, vomiting blood and melena. Hp culture and drug susceptibility test were carried out with gastric antrum mucosa before treatment. All the patients completed 2 weeks of standardized Hp eradication therapy and had ¹³C urea breath test 1 month after that, which was used to evaluate the curative effect. The DNA of gastric mucosa after RUT was analyzed and CYP2C19 gene polymorphism was detected. Children were grouped according to metabolic type. Combined with the results of Hp culture and drug susceptibility, the relationship between CYP2C19 gene polymorphism and the efficacy of Hp eradicative treatment was analyzed in children. Chi square test was used for row and column variables, and Fisher exact test was used for comparison between groups. Results: One hundred and twenty five children were enrolled in the study, of whom 76 were males and 49 females. The genetic polymorphism of CYP2C19 in these children found poor metabolizer (PM) of 30.4% (38/125), intermediate metabolizer (IM) of 20.8% (26/125), normal metabolizer (NM) of 47.2% (59/125), rapid metabolizer (RM) of 1.6% (2/125), and ultrarapid metabolizer (UM) of 0. There were statistically significant in positive rate of Hp culture among these groups (χ²=124.00, P<0.001). In addition, the successful rates of Hp eradication in PM, IM, NM and RM genotypes were 84.2% (32/38), 53.8% (14/26), 67.8% (40/59), and 0, respectively, with significant differences (χ²=11.35, P=0.010); those in IM genotype was significantly lower than that in PM genotype (P=0.011). With the same standard triple Hp eradicative regimen, the successful rate of Hp eradication for IM type was 8/19, which was lower than that of PM (80.0%, 24/30) and NM type (77.3%, 34/44) (P=0.007 and 0.007, respectively). There was a significant difference in the efficacy of Hp eradication treatment among different genotypes (χ²=9.72, P=0.008). According to the clarithromycin susceptibility result, the successful rate of Hp eradication treatment for IM genotype was 4/15 in the sensitive group and 4/4 in the drug-resistant group (χ²=6.97, P=0.018). Conclusions: The genetic polymorphism of CYP2C19 in children is closely related to the efficacy of Hp eradication treatment. PM has a higher successful rate of eradication treatment than the other genotypes.