A/APublished research associates this genotype with "non-secretor" status — associated with resistance to some of the most common norovirus strains, and a distinct gut microbiome profile compared to secretors.
G/AOne copy of each allele. Typically still a secretor, though with somewhat reduced antigen expression.
G/GPublished research associates this genotype with "secretor" status — ABO blood-type antigens are also present in saliva and other bodily fluids, and this genotype is associated with a different gut microbiome composition and altered susceptibility to certain norovirus strains.
Source: Kindberg et al. 2007, Journal of General Virology — FUT2 genotype and norovirus susceptibility.