ABO (gene)

ABO (gene) is a gene present in humans that is responsible for producing the ABO blood group system, one of the primary blood types used in medical transfusions. The ABO gene is located on the long arm of chromosome 9 at position 34.1-34.2, spanning over 18,000 base pairs. The gene encodes a glycosyltransferase, an enzyme that transfers sugar molecules to proteins and lipids.

Function

The glycosyltransferase enzyme produced by the ABO gene plays a crucial role in the synthesis of ABO blood group antigens. These antigens are found on the surface of red blood cells and other cells in the body. The specific antigen produced (A, B, or O) depends on the version (allele) of the ABO gene that an individual has inherited.

Genetic Variation

There are three main alleles of the ABO gene: A, B, and O. The A and B alleles encode slightly different versions of the glycosyltransferase enzyme, leading to the production of A and B antigens, respectively. The O allele does not produce a functional enzyme, resulting in the absence of A and B antigens (the O blood type).

Clinical Significance

The ABO blood group system is critical in blood transfusion and organ transplantation. Mismatched blood types can lead to severe immune reactions, potentially causing organ failure or death. The ABO gene has also been associated with various diseases, including cardiovascular disease and certain types of cancer.

See Also

• Blood type
• Glycosyltransferase
• Blood transfusion
• Organ transplantation