[Relationship between gene polymorphisms in MMP-9 and Helicobacter pylori-related upper gastrointestinal disease in children]

To investigate the relationship of the promoter of matrix metalloproteinase-9 (MMP-9) gene polymorphisms with the susceptibility and clinical features of Helicobacter pylori (H. pylori)-related chronic gastritis and duodenal ulcer in children.One hundred children with chronic gastritis, 32 children with duodenal ulcer and 102 healthy children were enrolled.The promoter of MMP-9-1562C/T gene polymorphisms were genotyped by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) and sequencing. MMP-9 mRNA expression in gastric mucosa was confirmed by reverse transcription polymerase chain reaction.The genotype distributions and allele frequencies of MMP-9-1562C/T gene polymorphisms were similar in gastric upper gastrointestinal disease and healthy subjects. The relative risk for H.pylori infection in C/C genetype carriers was 3.1 times as high as that in T allele (C/T+T/T) carriers in children with chronic gastritis. MMP-9-1562 C/T gene polymorphisms did not affect MMP-9 mRNA expression level.These data suggest that MMP-9-1562 C/T gene polymorphisms are not associated with susceptibility to chronic gastritis and duodenal ulcer in children. The C/C genotype of MMP-9-1562 C/T gene polymorphism might be associated with H.pylori infection.