FUT2 (secretor status)

rs601338

FUT2 helps produce certain sugar structures in secretions and on mucosal surfaces. The rs601338 variant can affect secretor status and has been associated with differences in susceptibility to some norovirus strains, vitamin B12 levels and the microbiome. How informative rs601338 is on its own also depends on ancestry and other FUT2 variants.

Key points

About 20 percent of Europeans are non-secretors (rs601338 A/A).
Non-secretor status protects against some norovirus strains, but not all.
FUT2 influences the vitamin B12 level and the bacterial composition in the gut.

#Secretor and non-secretor

FUT2 encodes an enzyme that produces certain sugar structures in bodily secretions. With an inactivating FUT2 variant, some or all of these structures are absent. Some norovirus strains use such sugars as binding sites, but susceptibility also depends on the viral strain and other factors.

#Wide-ranging side effects

Studies report associations between FUT2 variants, vitamin B12 levels, gut microbiome composition and some conditions. These associations can differ by population and trait; they do not predict an individual's outcome.

#Context

FUT2 is a good example of a single variant having many small effects at once. Genome shows the genotype; the individual associations are documented to differing degrees depending on the question.

What Genome measures. The genotype at rs601338 (W143X), a common marker of secretor status. It does not capture every functional FUT2 variant.

Sources

1Ferrer-Admetlla et al., 2009 A natural history of FUT2 polymorphism in humans. Molecular Biology and Evolution 26:1993-2003. doi.org/10.1093/molbev/msp108
2Hazra et al., 2008 Common variants of FUT2 are associated with plasma vitamin B12 levels. Nature Genetics 40:1160-1162. doi.org/10.1038/ng.210