Figure 3. Secretor status.
• ~80% of humans are secretors, meaning their H antigens are released from the originating cell. FUT2, the causal locus for secretion, encodes a fucosyltransferase that produces soluble H antigen which is decorated by ABO oligosaccharides.
• Secretor status is autosomal dominant and non-secretors are homozygous for nonsense mutations at the FUT2 locus.
• These soluble antigens can be found in bodily fluids beyond the circulatory system such as saliva, tears, urine, and mucus.