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💀anatomy and physiology i review

Blood Group Genetics

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Blood group genetics refers to the inheritance and expression of different blood group antigens on the surface of red blood cells. These antigens, determined by specific genes, are the basis for the ABO and Rh blood group systems, which are clinically important in blood typing, transfusion medicine, and organ transplantation.

5 Must Know Facts For Your Next Test

  1. The ABO blood group system is determined by the presence or absence of A and B antigens on the surface of red blood cells, which are encoded by the ABO gene.
  2. The Rh blood group system is determined by the presence or absence of the Rh (D) antigen, which is encoded by the RHD gene.
  3. Individuals can inherit different combinations of ABO and Rh alleles, resulting in the various blood types (A, B, AB, and O) and Rh status (positive or negative).
  4. Blood group genetics play a crucial role in transfusion medicine, as incompatible blood types can lead to potentially life-threatening immune reactions.
  5. Understanding blood group genetics is also important in organ transplantation, as matching blood types between donors and recipients can improve the success of the transplant.

Review Questions

  • Explain the role of the ABO blood group system in blood typing and its clinical significance.
    • The ABO blood group system is based on the presence or absence of A and B antigens on the surface of red blood cells. Individuals can have type A (with A antigens), type B (with B antigens), type AB (with both A and B antigens), or type O (with neither A nor B antigens). This system is clinically important because individuals can develop antibodies against the antigens they lack, which can lead to potentially life-threatening immune reactions during blood transfusions or organ transplantation if the donor and recipient have incompatible blood types.
  • Describe the role of the Rh blood group system in blood typing and its significance in pregnancy.
    • The Rh blood group system is based on the presence or absence of the Rh (D) antigen on the surface of red blood cells. Individuals can be Rh-positive (with the Rh antigen) or Rh-negative (without the Rh antigen). During pregnancy, if the mother is Rh-negative and the fetus is Rh-positive, the mother's immune system may produce antibodies against the Rh antigen, a condition known as Rh incompatibility. This can lead to complications such as hemolytic disease of the newborn, which can be prevented through the administration of Rh immunoglobulin during pregnancy and after delivery.
  • Analyze how an understanding of blood group genetics can impact the field of organ transplantation.
    • In the context of organ transplantation, a deep understanding of blood group genetics is crucial. Matching the ABO and Rh blood types between the donor and recipient is essential to minimize the risk of rejection and ensure the success of the transplant. Individuals with type AB blood are considered universal recipients, as they can accept organs from donors of any blood type. Conversely, individuals with type O blood are considered universal donors, as their organs can be transplanted into recipients of any blood type. Additionally, Rh compatibility is also important, as Rh-negative recipients should receive organs from Rh-negative donors to avoid potential complications. By carefully considering the genetic factors underlying blood group systems, healthcare professionals can optimize the chances of successful organ transplantation.