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Blood group gene family

Reviewed May 2008

What are the blood group genes?

Blood is classified into different groups according to the presence or absence of molecules called antigens on the surface of every red blood cell in a person's body. The genes that provide instructions for making proteins that contain antigens are known as blood group determining genes. Antigens determine blood type and can either be proteins or complexes of sugar molecules (polysaccharides). Blood group proteins, which carry antigens, serve a variety of functions within the cell membrane of red blood cells. These protein functions include transporting other proteins and molecules into and out of the cell, maintaining cell structure, attaching to other cells and molecules, and participating in chemical reactions.

Blood group antigens play a role in recognizing foreign cells in the bloodstream. For example, if a person with blood type A receives a blood transfusion with blood type B, the recipient's immune system will recognize the type B cells as foreign and mount an immune response. Antibodies against type B blood cells (anti-B antibodies) are made, which attack and destroy the type B blood cells. This sort of blood type mismatch can lead to illness. Some blood types are associated with more severe immune reactions than others. The blood type of donated cells, or tissues in the case of organ donation, is checked before being given to a recipient in order to prevent this immune response.

There are 29 recognized blood groups, most involving only one gene. Variations (polymorphisms) within the genes that determine blood group give rise to the different antigens for a particular blood group protein. For example, changes in a few DNA building blocks (nucleotides) in the ABO gene give rise to the A, B, and O blood types of the ABO blood group. The changes that occur in the genes that determine blood group typically affect only blood type and are not associated with adverse health conditions, although exceptions do occur.

Which gene is included in the blood group gene family?

The HUGO Gene Nomenclature Committee (HGNC) provides a list of genes in the blood group familyThis link leads to a site outside Genetics Home Reference..

Genetics Home Reference provides additional information about this member of the blood group gene family: XK.

What conditions are related to genes in the blood group gene family?

Genetics Home Reference includes these conditions related to genes in the blood group gene family:

Where can I find additional information about the blood group gene family?

You may find the following resources about the blood group gene family helpful.

Where can I find general information about genes and gene families?

The Handbook provides basic information about genetics in clear language.

What glossary definitions help with understanding the blood group (blood group determining genes) gene family?

antibody ; antigens ; cell ; cell membrane ; DNA ; gene ; immune response ; immune system ; molecule ; nucleotide ; polymorphism ; protein ; red blood cell ; syndrome ; tissue

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

References (10 links)


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.

Reviewed: May 2008
Published: January 30, 2009