Hemophilia Chapter 10 Flashcards

Hemophilia Overview

• Hemophilia is classified into two main types: Hemophilia A (mutation of the F8 gene) and Hemophilia B (mutation of the F9 gene).
• Both types exhibit X-linked recessive inheritance patterns, primarily affecting males.

Hemophilia A

• Caused by mutations in the F8 gene, leading to impaired production of coagulation Factor VIII.
• Factor VIII is crucial for proper blood coagulation.
• Severity classifications:
  • Severe: < 1% normal factor activity; spontaneous joint and muscle bleeding occurs.
  • Moderate: 1-5% normal factor activity; bleeding from minor trauma and postoperative.
  • Mild: 5-40% normal factor activity; bleeding occurs post-operatively or after mild trauma, no spontaneous bleeding.

Hemophilia B

• Caused by mutations in the F9 gene, resulting in insufficient levels of coagulation Factor IX.
• Also characterized by X-linked recessive inheritance.

Variable Expressivity

• Refers to the varying expression of disease symptoms among affected individuals, demonstrating different levels of severity.

Laboratory Findings

• Initial lab findings for both Hemophilia A and B include:
  • Prolonged activated partial thromboplastin time (APTT).
  • Normal prothrombin time (PT), bleeding time, and fibrinogen levels.
• APTT is part of the intrinsic pathway of the coagulation cascade.

Genetic Transmission

• Hemophilia is not inherited from father to son because males transmit only Y chromosomes to male offspring.
• Commonly affected joints in severe hemophilia include knees, ankles, and elbows.

De Novo Mutations

• Alterations that occur for the first time in a family member, not inherited.
• Key for understanding unique cases of hemophilia.

Screening and Monitoring

• APTT is most sensitive for detecting moderate to severe hemophilia.
• APTT is also useful for monitoring heparin therapy and detecting clotting inhibitors.
• Prothrombin time (PT) measures the extrinsic pathway, useful for liver function and monitoring long-term anticoagulant therapy.

Testing and Counseling

• Essential screenings for bleeding disorders include APTT, PT, bleeding time, and platelet count.
• Specific coagulation factors are assessed based on initial screening results.

Management & Treatment

• Treatments to increase levels of factors VIII and IX include:
  • Hormonal treatments (estrogens, oral contraceptives).
  • Epinephrine and desmopressin acetate, the latter enhancing factor VIII levels.
  • Vigorous exercise can aid in management.

Platelet Function Testing

• Bleeding time is the best screening test for platelet function disorders, prolonged in von Willebrand's disease and qualitative platelet disorders.

Mutation Types in Hemophilia

• Mild to moderate disease often linked to point or missense mutations.
• Severe disease typically associated with deletion mutations that respond poorly to therapy.
• Males with hemophilia pass the mutation to all daughters but none of their sons.

Explore key concepts and definitions related to Hemophilia in this comprehensive flashcard quiz. Understand the coagulation cascade, mutations involved in Hemophilia A and B, and their inheritance patterns. Perfect for studying or reinforcing knowledge on this important topic.