FUT2 secretor status

# What is the FUT2 secretory status? The FUT2 secretion status influences a variety of physiological processes. The FUT2 gene codes for the enzyme α(1,2)-fucosyltransferase, which is responsible for the synthesis of H antigens on the surface of mucosal and salivary cells. These antigens are precursor molecules for the formation of the blood group antigens of the ABO system. Individuals with the so-called secretor status have at least one functional FUT2 allele and are therefore able to produce these H antigens in their body fluids such as saliva, mucus and digestive secretions. In contrast, "non-secretors" have a reduced or no ability to synthesize these antigens due to a mutation in the FUT2 gene that restricts enzyme activity. Secretor status affects not only blood type, but also various aspects of health, including susceptibility to certain infectious diseases and chronic conditions. In addition, secretor status can have an impact on the gut microbiota, as H antigens in the mucosa play a role in colonization by certain bacterial strains. This in turn can modulate the immune response and the absorption of nutrients, including the regulation of vitamin B12 in the blood. # Influence of secretor status on vitamin B12 Secretor status, which is mediated by the FUT2 gene, has a significant influence on the metabolism of vitamin B12, especially on its transport and storage in the body. Vitamin B12, which is essential for cell division and the function of the nervous system, is transported in the blood bound to two main proteins: Haptocorrin and transcobalamin. Research shows that secretor status primarily affects the concentration of haptocorrin, while transcobalamin is less affected. Non-secretors who are unable to produce H antigens due to an inactive FUT2 gene tend to have lower concentrations of vitamin B12 bound to haptocorrin. This suggests that secretor status may influence the availability of vitamin B12, which in turn could have an impact on vitamin B12 status and related health parameters. > ## Good to know > > FUT2 secretor status may influence how well certain viruses, such as noroviruses, can attach to the mucosa, meaning that non-secretors may have partial natural resistance to certain viral infections. # Susceptibility to infections and chronic diseases Individuals with an active FUT2 gene, i.e. secretors, show a different immune response than non-secretors. Secretors appear to be less susceptible to certain viral and bacterial infections because the H antigens they produce can serve as binding sites for pathogens in the mucous membranes. Non-secretors may therefore have a higher risk of certain infections and associated complications. In addition, there is evidence that secretor status is associated with the development of chronic diseases such as inflammatory bowel disease and autoimmune diseases. These correlations highlight the far-reaching impact of FUT2 secretor status on human health. # What does genetics have to do with it? The FUT2 genotype plays a crucial role in categorizing a person as "secretor" or "non-secretor". The SNP rs601338 in the FUT2 gene is strongly associated with secretor status in Caucasian populations. A particular variant of this SNP leads to a loss of function of the FUT2 gene, resulting in the affected individual not producing a functional enzyme that enables the synthesis of H antigens. These individuals are referred to as "non-secretors" as they do not secrete blood group antigens in their body fluids. This genotype is associated with various health effects, including increased susceptibility to certain infections, particularly gastrointestinal diseases. The SNP rs1047781 in the FUT2 gene is of similar significance, but in the Japanese population. Here, too, the variant of this SNP influences the activity of the FUT2 gene and thus the secretor status. People with the corresponding variant in rs1047781 are just as frequently "non-secretors". This also has an impact on their susceptibility to certain diseases, although the specific health risks may vary due to ethnic differences and associated environmental factors.