HealthMap

Secretor Status and the FUT2 Gene

Overview

• The FUT2 gene (Fucosyltransferase 2) is the primary genetic determinant responsible for governing the secretion of ABO blood group antigens into bodily fluids.
• Individuals who possess a functional copy of this gene are classified as Secretors, while those with homozygous inactivating mutations are classified as Non-Secretors.

Biochemical Mechanism

• The FUT2 gene encodes an enzyme called alpha-(1,2)-fucosyltransferase.
• This enzyme is required in the mucus-secreting secretory tissues (such as saliva, sweat, tears, gastric juices, and milk) to add a fucose sugar to precursor molecules.
• Adding this fucose creates the H antigen, which is the essential chemical foundation upon which A and B blood group antigens are built and subsequently secreted.

Key Physiological Distinctions

• Secretors (SeSe or Sese):
• Express ABO antigens in bodily fluids and mucosal linings.
• Comprise approximately 80% of the human population.
• Maintain a protective mucosal barrier with specific glycoproteins that influence microbial flora and immune defense.

• Non-Secretors (sese):
• Lack the functional alpha-(1,2)-fucosyltransferase enzyme in mucosal secretions.
• Comprise approximately 20% of the population.
• Do not release ABO antigens into saliva or gut linings, which alters their susceptibility profile to certain infections, autoimmune challenges, and digestive variations.