W1-10 Hemogloinopathies and associated anemias
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Questions and Answers

Which of the following is the underlying mutation in HbC disease?

  • Polymorphism in the α-globin gene
  • Insertion mutation in the γ-globin gene
  • Deletion of the β-globin gene
  • Point mutation (Glu —> Val at amino acid 6) in β-globin (HBB) gene (correct)
  • What is the major cause of pathogenesis in sickle cell disease?

  • Decreased production of RBCs
  • Polymerization of deoxygenated HbS (correct)
  • Disruption of RBC membrane integrity
  • Oxidative damage to hemoglobin
  • What type of anemia is sickle cell disease?

  • Aplastic anemia
  • Macrocytic hyperchromic anemia
  • Microcytic hypochromic anemia
  • Normocytic hemolytic anemia with extravascular hemolysis (correct)
  • Which population is primarily affected by sickle cell disease?

    <p>African Americans</p> Signup and view all the answers

    What is the genetic nature of sickle cell disease?

    <p>Autosomal recessive disorder</p> Signup and view all the answers

    What proportion of sickled RBCs undergo intravascular hemolysis?

    <p>A small proportion</p> Signup and view all the answers

    Which condition is characterized by the loss of three α-globin genes, relative excess of β-globin chains, and the formation of stable β4 tetramers?

    <p>HbH disease</p> Signup and view all the answers

    What is the consequence of deletion of all four α-globin genes?

    <p>Lethal in utero due to virtually no oxygen-delivering capacity</p> Signup and view all the answers

    In which condition does the excess in γ-globin chains lead to the formation of γ4 tetramers (Hb Barts)?

    <p>Hydrops fetalis</p> Signup and view all the answers

    Which condition is characterized by the proportional severity of the disease to the number of missing α-globin genes?

    <p>Silent carrier state</p> Signup and view all the answers

    Which test is considered the best for diagnosing sickle cell disease?

    <p>High performance liquid chromatography (HPLC)</p> Signup and view all the answers

    What is the characteristic feature seen in HbC disease on peripheral blood smear (PBS)?

    <p>HbC crystals</p> Signup and view all the answers

    What is the clinical behavior of HbSC disease?

    <p>Similar to sickle cell anemia (SCA) but with a milder clinical course</p> Signup and view all the answers

    What demographic is endemic for thalassemias?

    <p>Mediterranean, African, and Asian regions</p> Signup and view all the answers

    Which type of thalassemia is characterized by decreased/absent α-globin chains with excess of β-globin chains?

    <p>Alpha-thalassemia</p> Signup and view all the answers

    What is the primary mechanism of anemia in β-thalassemia?

    <p>Inadequate HbA formation</p> Signup and view all the answers

    What is the characteristic feature of HbC disease in terms of erythrocyte morphology?

    <p>Target cells with increased MCHC</p> Signup and view all the answers

    Which test is used in review books but is not clinically indicated for screening or managing sickle cell disorders?

    <p>&quot;Sickledex&quot; sodium metabisulfite test</p> Signup and view all the answers

    What does the presence of Howell-Jolly bodies in patients with sickle cell anemia indicate?

    <p>Hyposplenism or autosplenectomy</p> Signup and view all the answers

    What is the result of a high serum bilirubin level in patients with sickle cell anemia?

    <p>Intravascular hemolysis</p> Signup and view all the answers

    What feature distinguishes HbSC disease from sickle cell anemia (SCA)?

    <p>Presence of nucleated RBCs in peripheral blood smear (PBS)</p> Signup and view all the answers

    What is the primary consequence of excess unpaired α-chains in β-thalassemia?

    <p>Production of insoluble hemoglobin precipitates</p> Signup and view all the answers

    What is the primary event in the pathogenesis of β-thalassemia?

    <p>Destruction of erythroid precursors</p> Signup and view all the answers

    In β-thalassemia, what results in extensive extramedullary hematopoiesis and hepato- and splenomegaly?

    <p>Erythroferrone release</p> Signup and view all the answers

    What is the genetic basis for the clinical classification of β-thalassemia?

    <p>Severity of anemia and gene defect</p> Signup and view all the answers

    Which type of β-thalassemia is characterized by severe anemia but does not require regular blood transfusions?

    <p>β-thal intermedia</p> Signup and view all the answers

    What is a characteristic morphological change in the peripheral blood smear (PBS) of β-thalassemia major?

    <p>Microcytic, hypochromic cells with basophilic stippling</p> Signup and view all the answers

    What is a common complication in β-thalassemia that leads to 'bronze diabetes'?

    <p>Secondary hemochromatosis</p> Signup and view all the answers

    What is the cause of α-thalassemia?

    <p>Deletion of one or more α-globin genes</p> Signup and view all the answers

    In α-thalassemia, which type of genetic deletion results in the most severe manifestations?

    <p>-- -- -- +</p> Signup and view all the answers

    What type of hemoglobin is predominant in normal adult individuals?

    <p>HbA/HbA</p> Signup and view all the answers

    Which type of Hb spectrum (%) is characteristic of sickle cell trait?

    <p>HbA/HbS</p> Signup and view all the answers

    What are the predominant types of hemoglobin in sickle cell trait?

    <p>HbS/HbC</p> Signup and view all the answers

    What is the most common manifestation of vaso-occlusion in sickle cell disease?

    <p>Acute chest syndrome</p> Signup and view all the answers

    What is the primary cause of death in children with sickle cell disease?

    <p>Infection with encapsulated bacteria</p> Signup and view all the answers

    What does the presence of Howell-Jolly bodies on peripheral blood smear indicate in sickle cell disease?

    <p>Autosplenectomy</p> Signup and view all the answers

    What is the common cause of death in adults with sickle cell disease?

    <p>Acute chest syndrome</p> Signup and view all the answers

    What condition results from the infection of red cell progenitors by parvovirus B19 in sickle cell disease?

    <p>Aplastic crisis</p> Signup and view all the answers

    Which manifestation in sickle cell disease is characterized by rapid splenic enlargement, hypovolemia, and shock?

    <p>Sequestration crisis</p> Signup and view all the answers

    What is the primary cause of chronic anemia in sickle cell anemia?

    <p>Irreversible sickled RBCs</p> Signup and view all the answers

    Which type of crisis in sickle cell disease is associated with an acute drop in hemoglobin and high reticulocyte count?

    <p>Hyperhemolytic crisis</p> Signup and view all the answers

    What is the characteristic bone change seen in individuals with sickle cell anemia?

    <p>&quot;Crew-cut&quot; appearance on skull x-ray</p> Signup and view all the answers

    "Dactylitis" (hand-foot syndrome) in infants with sickle cell disease is characterized by:

    <p>Bone infarcts with swelling of hands and feet</p> Signup and view all the answers

    What is the primary consequence of deletion of all four α-globin genes?

    <p>Excess of γ-globin and formation of γ-globin tetramers (Hb Barts)</p> Signup and view all the answers

    What is the characteristic morphological change in the peripheral blood smear (PBS) of HbH Disease?

    <p>HbH aggregates</p> Signup and view all the answers

    What condition results from a decline in Hb Portland production in Trimester 3?

    <p>Hydrops fetalis</p> Signup and view all the answers

    Which manifestation is characteristic of Hb Barts Disease?

    <p>Severe pallor, generalized edema, and massive hepatosplenomegaly</p> Signup and view all the answers

    What is the clinical presentation of α-Thal: Hb Barts Disease (-/- -/-)?

    <p>Severe pallor, generalized edema, and massive hepatosplenomegaly</p> Signup and view all the answers

    What does the excess in γ-globin chains lead to in Hb Barts Disease?

    <p>Formation of γ-globin tetramers (Hb Barts)</p> Signup and view all the answers

    What is the primary mechanism of anemia in β-thalassemia?

    <p>Reduced hemoglobin synthesis</p> Signup and view all the answers

    What is the characteristic bone change seen in individuals with sickle cell anemia?

    <p>Avascular necrosis of the hip</p> Signup and view all the answers

    What is the consequence of deletion of all four α-globin genes?

    <p>Hydrops fetalis</p> Signup and view all the answers

    Which condition exhibits manifestations similar to β-thalassemia minor?

    <p>Alpha-thalassemia trait</p> Signup and view all the answers

    What is the genetic nature of sickle cell disease?

    <p>Autosomal recessive</p> Signup and view all the answers

    What is the clinical behavior of HbSC disease?

    <p>More severe than HbAS but milder than HbSS</p> Signup and view all the answers

    Which type of crisis in sickle cell disease is associated with an acute drop in hemoglobin and high reticulocyte count?

    <p>Aplastic crisis</p> Signup and view all the answers

    What is the common cause of death in adults with sickle cell disease?

    <p>Acute chest syndrome</p> Signup and view all the answers

    Which type of thalassemia is characterized by decreased/absent α-globin chains with excess of β-globin chains?

    <p>Beta-thalassemia minor</p> Signup and view all the answers

    What is the primary event in the pathogenesis of β-thalassemia?

    <p>Reduced hemoglobin synthesis</p> Signup and view all the answers

    What demographic is endemic for thalassemias?

    <p>Mediterranean and Southeast Asians</p> Signup and view all the answers

    Which population is primarily affected by sickle cell disease?

    <p>Africans and African Americans</p> Signup and view all the answers

    Which type of hemoglobin is predominant in normal adult individuals?

    <p>HbA</p> Signup and view all the answers

    What is the primary cause of chronic anemia in sickle cell anemia?

    <p>Vaso-occlusion</p> Signup and view all the answers

    What is the genetic basis for the clinical classification of β-thalassemia?

    <p>Reduced expression of beta-hemoglobin</p> Signup and view all the answers

    What feature distinguishes HbSC disease from sickle cell anemia (SCA)?

    <p>Different types of hemoglobin present</p> Signup and view all the answers

    What is the primary pathophysiological mechanism in β-thalassemia major?

    <p>Severely reduced production of β-Hb chains</p> Signup and view all the answers

    In β-thalassemia, what is the specific consequence of the surplus of β-like chains?

    <p>Formation of homo-tetramers</p> Signup and view all the answers

    What is the characteristic phenotype of HbE/HbE homozygotes?

    <p>Mild hypochromic, microcytic anemia</p> Signup and view all the answers

    Which type of thalassemia exhibits a mixed process as it changes both the content and amount of protein?

    <p>HbE/ -thalassemia compound heterozygotes</p> Signup and view all the answers

    What is the primary consequence of deletion of all four α-globin genes?

    <p>Surplus production of γ-Hb chains</p> Signup and view all the answers

    What is the underlying mutation in HbC disease?

    <p>Substitution GAG-to-AAG in codon 26 leading to Glu26Lys</p> Signup and view all the answers

    What is the characteristic feature seen in HbC disease on peripheral blood smear (PBS)?

    <p>Presence of Howell-Jolly bodies</p> Signup and view all the answers

    Which condition results from the infection of red cell progenitors by parvovirus B19 in sickle cell disease?

    <p>-Thalassemia trait</p> Signup and view all the answers

    Study Notes

    • The text discusses sickle cell disease (SCD) and associated anemias, with a focus on sickle cell disease, HbC disease, and β- and α-thalassemia.
    • Sickle cell disease is a normocytic hemolytic anemia with extravascular hemolysis, affecting African Americans and caused by a point mutation in the β-globin gene (HBB).
    • The disease results from the formation of sickle polymers when HbS deoxygenates, leading to sickled RBCs and various complications.
    • Sickle cell anemia (homozygosity) presents with severe anemia, irreversible sickled RBCs, and frequent crises, while sickle cell trait (heterozygosity) is usually asymptomatic.
    • Enhancing factors for sickling include hypoxia, dehydration, acidosis, and high altitude, while preventive factors include HbF and hydroxyurea.
    • Sickle cell disease crises include vaso-occlusive, sequestration, aplastic, and hyperhemolytic, each presenting with distinct clinical features and complications.
    • Vaso-occlusive crises result from vaso-occlusion and ischemia caused by sickled RBCs, leading to pain, infarctions, and organ damage.
    • Sequestration crisis occurs in children with an intact spleen, resulting in rapid splenic enlargement, hypovolemia, and shock.
    • Aplastic crisis is caused by infection of red cell progenitors by parvovirus B19, leading to transient cessation of erythropoiesis and worsening anemia.
    • Hyperhemolytic crisis is characterized by an acute drop in hemoglobin and high reticulocyte count, often resulting from infection or other stressors.
    • Complications of sickle cell disease include splenic infarcts, infections, and bone changes, as well as damage to various organs.
    • Treatments for sickle cell disease include supportive care, hydroxyurea, and bone marrow transplantation, while prevention includes newborn screening, gene therapy, and vaccinations.
    • SCD can lead to chronic anemia, jaundice, pigmented gallstones, and reticulocytosis, as well as crises and organ damage if left untreated.
    • HbC disease is caused by a different mutation in the β-globin gene, leading to the production of HbC and HbE, which form inclusions in RBCs.
    • β- and α-thalassemia are genetic disorders affecting the production of β- or α-globin chains, respectively, leading to various hemoglobin abnormalities and complications.

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    Description

    Explore the etiology, pathogenesis, morphological changes, clinical presentation, complications, laboratory data, treatment, and prognosis of sickle cell disease. Understand the implications of splenic infarct and Howell-Jolly bodies.

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