A blood type is a classification of blood, based on the presence and absence of antibodies and inherited antigenic substances on the surface of red blood cells (RBCs). These antigens may be proteins, carbohydrates, glycoproteins, or glycolipids, depending on the blood group system. Some of these antigens are also present on the surface of other types of cells of various tissues. Several of these red blood cell surface antigens can stem from one allele and collectively form a blood group system.
Rh disease is a type of hemolytic disease of the fetus and newborn (HDFN). HDFN due to anti-D antibodies is the proper and currently used name for this disease as the Rh blood group system actually has more than 50 antigens and not only the D-antigen. The term "Rh Disease" is commonly used to refer to HDFN due to anti-D antibodies, and prior to the discovery of anti-Rho(D) immune globulin, it was the most common type of HDFN. The disease ranges from mild to severe, and occurs in the second or subsequent pregnancies of Rh-D negative women when the biologic father is Rh-D positive.
Duffy antigen/chemokine receptor (DARC), also known as Fy glycoprotein (FY) or CD234, is a protein that in humans is encoded by the ACKR1 gene.
The ABO blood group system is used to denote the presence of one, both, or neither of the A and B antigens on erythrocytes. For human blood transfusions, it is the most important of the 44 different blood type classification systems currently recognized by the International Society of Blood Transfusions (ISBT) as of December 2022. A mismatch in this, or any other serotype, can cause a potentially fatal adverse reaction after a transfusion, or an unwanted immune response to an organ transplant. The associated anti-A and anti-B antibodies are usually IgM antibodies, produced in the first years of life by sensitization to environmental substances such as food, bacteria, and viruses.
The Kell antigen system is a human blood group system, that is, a group of antigens on the human red blood cell surface which are important determinants of blood type and are targets for autoimmune or alloimmune diseases which destroy red blood cells. The Kell antigens are K, k, Kpa, Kpb, Jsa and Jsb. The Kell antigens are peptides found within the Kell protein, a 93-kilodalton transmembrane zinc-dependent endopeptidase which is responsible for cleaving endothelin-3.
XK is a protein found on human red blood cells and other tissues which is responsible for the Kx antigen which helps determine a person's blood type.
The Rh blood group system is a human blood group system. It contains proteins on the surface of red blood cells. After the ABO blood group system, it is the most likely to be involved in transfusion reactions. The Rh blood group system consisted of 49 defined blood group antigens in 2005. As of 2023, there are over 50 antigens among which the five antigens D, C, c, E, and e are the most important. There is no d antigen. Rh(D) status of an individual is normally described with a positive (+) or negative (−) suffix after the ABO type. The terms Rh factor, Rh positive, and Rh negative refer to the Rh(D) antigen only. Antibodies to Rh antigens can be involved in hemolytic transfusion reactions and antibodies to the Rh(D) and Rh antigens confer significant risk of hemolytic disease of the fetus and newborn
McLeod syndrome is an X-linked recessive genetic disorder that may affect the blood, brain, peripheral nerves, muscle, and heart. It is caused by a variety of recessively inherited mutations in the XK gene on the X chromosome. The gene is responsible for producing the Kx protein, a secondary supportive protein for the Kell antigen on the red blood cell surface.
Blood group Rh(CE) polypeptide is a protein that in humans is encoded by the RHCE gene. RHCE has also recently been designated CD240CE.
Glycophorin A (MNS blood group), also known as GYPA, is a protein which in humans is encoded by the GYPA gene. GYPA has also recently been designated CD235a (cluster of differentiation 235a).
Rh-associated glycoprotein (RHAG) is an ammonia transporter protein that in humans is encoded by the RHAG gene. RHAG has also recently been designated CD241. Mutations in the RHAG gene can cause stomatocytosis.
Glycophorin B (MNS blood group) (gene designation GYPB) also known as sialoglycoprotein delta and SS-active sialoglycoprotein is a protein which in humans is encoded by the GYPB gene. GYPB has also recently been designated CD235b (cluster of differentiation 235b).
Basal cell adhesion molecule, also known as Lutheran antigen, is a plasma membrane glycoprotein that in humans is encoded by the BCAM gene. BCAM has also recently been designated CD239.
Galactoside 2-alpha-L-fucosyltransferase 1 is an enzyme that in humans is encoded by the FUT1 gene.
Urea transporter 1 is a protein that in humans is encoded by the SLC14A1 gene.
Ecto-ADP-ribosyltransferase 4 is an enzyme that in humans is encoded by the ART4 gene. ART4 has also been designated as CD297.
Erythroid membrane-associated protein is a protein that in humans is responsible for the Scianna blood group system, and is encoded by the ERMAP gene.
Histo-blood group ABO system transferase is an enzyme with glycosyltransferase activity, which is encoded by the ABO gene in humans. It is ubiquitously expressed in many tissues and cell types. ABO determines the ABO blood group of an individual by modifying the oligosaccharides on cell surface glycoproteins. Variations in the sequence of the protein between individuals determine the type of modification and the blood group. The ABO gene also contains one of 27 SNPs associated with increased risk of coronary artery disease.
HMG box transcription factor BBX also known as bobby sox homolog or HMG box-containing protein 2 is a protein that in humans is encoded by the BBX gene.
Willy Albert Flegel is a German-American medical researcher, geneticist, and physician who is best known for his work in the field of the Rh blood group. Flegel is the chief of the laboratory services section of the Department of Transfusion Medicine at the National Institutes of Health Clinical Center (NIH).
