Vel blood group

Vel blood group is a rare blood group system that was discovered in 1952. It is characterized by the presence or absence of the Vel antigen on the red blood cells. The Vel blood group is clinically significant as it can cause hemolytic transfusion reactions and hemolytic disease of the newborn.

History

The Vel blood group was first identified in 1952 in a patient named Mrs. Vel. She experienced a severe transfusion reaction after receiving a blood transfusion. The cause of the reaction was found to be an unknown blood antigen, which was later named Vel.

Genetics

The Vel blood group is determined by the SMIM1 gene located on chromosome 1. The presence of the Vel antigen is associated with a specific variant of the SMIM1 gene. Individuals who lack the Vel antigen have a deletion in the SMIM1 gene.

Clinical significance

The Vel antigen is highly immunogenic, meaning it can stimulate an immune response. Individuals who lack the Vel antigen and are exposed to it through blood transfusion or pregnancy can produce antibodies against the Vel antigen. This can lead to hemolytic transfusion reactions or hemolytic disease of the newborn.

Testing

Testing for the Vel blood group is done using serological methods. However, due to the rarity of the Vel antigen, it can be difficult to find suitable test reagents. Molecular testing methods are also available and can be used to detect the presence or absence of the SMIM1 gene variant associated with the Vel antigen.

Prevalence

The Vel antigen is present in about 1 in 2500 individuals of European descent. It is less common in other populations. The frequency of Vel-negative individuals is estimated to be about 1 in 5000 in the general population.

See also

• Blood type
• Blood transfusion
• Hemolytic disease of the newborn
• Hemolytic transfusion reaction

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