A blood group determined by an antigen specified by the Le gene on human chromosome 19. The Lewis antigen is expressed on epithelial surfaces as well as erythrocytes. The Lewis gene encodes a fucosyltransferase, which adds fucose to the same heterosaccharoside precursor targeted by the glycotransferases encoded by the genes of the ABO blood group system. The bacterium that causes gastric ulcers attaches to the gastric mucosa by binding to receptors containing fucose. Therefore, individuals with the Lewis antigen on their mucosal surfaces are more susceptible to this disease. See AB antigens, blood group, Helicobacter pylori, Lutheran blood group.
Subjects: Genetics and Genomics — Medicine and Health.