Influence of host gene polymorphisms on development of gastroduodenal diseases

Helicobacter pylori infection remains the commonest chronic bacterial infection in the world and is associated with a variety of clinical outcomes that range from simple asymptomatic gastritis to more serious conditions such as peptic ulcer disease and gastric cancer. The key determinants of these outcomes are the severity and distribution of H. pylori-induced gastritis. Host genetic factors play an important role in influencing disease risk, but identifying candidate genes is a major challenge that has to stem from a profound understanding of the pathophysiology of the disease. In the case of H. pylori-associated disease, the initial search focused on candidate genes that attenuate gastric physiology and lead to a destructive chronic inflammatory response against the infection. In particular, certain cytokine and innate immune response gene polymorphisms appear to influence risk of gastric cancer and its precursor conditions. More recent genome-wide association studies have identified novel genetic markers that show impressive associations with gastric cancer risk but whose function remains unclear. Very recently, there has been progress in identifying genetic risk markers for acquisition of H. pylori infection, but there remains a lack of suitable markers for risk of peptic ulcer disease. Future research agenda should focus on identifying the full genetic risk profile for H. pylori-induced gastroduodenal disease. This will help target the population most at risk by directing eradication therapy and closer follow-up to the affected individuals.