What does this gene do?
The FUT2 genes interferes with vitamin B12 absorption. It also has a minor association with plasma homocysteine levels. Homocysteine is an amino acid that requires B vitamins to be broken down into further important body chemicals. This could have an indirect relationship with vitamin B levels, meaning that if you have inherited a variant of this gene, it could affect the circulating levels of B-vitamins in your blood. There is also limited evidence that FUT2 can influence the composition of your microbiome.
The risk allele is the G allele, it increases risk for vitamin B12 deficiency and is associated with lower vitamin B12 concentrations. It has been associated to helicobacter pylori infection, gastritis and inflammatory bowel diseases (Crohn’s disease and ulcerative colitis). GG genotypes have been mainly observed in Asian populations, and seen in about 20% of Europeans and African Americans
The variant with an A allele is seen as beneficial. There is an association with higher vitamin B12 levels and reduced susceptibility of bacterial infection. About 40% of Europeans and African Americans were observed to have the AA genotype.
Other genes that work together; MTHFR, MTR and MTRR genotypes.