study aimed to identify the role of TLR9 (rs352140) gene in suppressing or promoting the inflammation related to H. pylori infection in children.This cross-sectional study was conducted on 50 children with positive H. pylori infection and 50 age and sex matched, negative H. pylori children, all children undertook full history, complete clinical investigation, laboratory testing, upper digestive endoscopies and genotyping of TLR9 (rs352140).

H. pylori infection is acknowledged as one of the major causes of gastrointestinal bacterial infections globally, imposing a substantial load on public health organizations, mostly in low-resource countries . H. pylori infection continues to pose a substantial challenge, particularly in vulnerable populations like infants, despite the significant advance made in health care organization and medicine .

The implications of H. pylori infection in minors have a profound impact on numerous aspects of health and well-being, which extend beyond the gastrointestinal tract.

In addition to its immediate effect on the gastric mucosa integrity of, H. pylori infection has systemic impacts that can have a negative impact on, growth trajectories, the nutritional status and overall health results of children who are affected .

A variety of gastrointestinal disorders, involving moderate gastritis and additional serious diseases like peptic ulcer disease, have been correlated with chronic infection by H. pylori. In addition, epidemiologic evidence indicates a potential correlation between an elevated hazard for acquiring gastric adenocarcinoma and mucosa-associated lymphoid tissue lymphoma in later life and the acquisition of H. pylori infection during childhood. These long-term effects reinforce the urgent need to address H. pylori infection in children as a major community health importance .

Currently, there are numerous invasive and non-invasive diagnostic assessments accessible to identify H. pylori infection in children. However, tissue culture and the rapid urease test or concordant-positive histopathology tests remains the gold standard results .

Mast, macrophages, dendritic, eosinophils, neutrophils, and natural killer (NK) cells are cell actors of the innate immune system which provide antigen-independent defense against H. pylori infection .

Toll-like receptors (TLRs) are critical innate immunity regulators that can be stimulated upon the identifying of pathogen-associated molecular patterns (PAMPs) such as viral and bacterial ligands. They serve as the initial line of defense for the host against a variety of circumstances, involving H. pylori infection .

There are 13 TLRs (TLR1-13) in mammals, but only 10 (TLR1-10) are present in humans, but all are present in mice, with TLR10 being nonfunctional.

The human stomach's gastric epithelial cells are known to produce TLR4 and TLR9, which are crucial for innate immune signaling to H. pylori .

Inclusion Criteria:

1. children with age between 1 and 18 years with gastrointestinal symptoms that necessitates upper digestive endoscopy like:

   • persistent pain in the abdomen and/or the stomach,
   • Heartburn,
   • vomiting,
   • nausea.

2. children who showed red flag signs like :

   • anemia,
   • gastrointestinal hemorrhage,
   • failure to thrive,
   • increased ESR .

Exclusion Criteria:

• cases on proton pump inhibitors,
• those with substantial medical diseases,
• those with gastrointestinal conditions that could explain their stomach discomfort (such as celiac disease, functional abdominal pain and inflammatory bowel disease).