Hemoglobinopathies

Question 1

Polypeptide chains in HbF

Answer 1

alpha 2 gamma 2

Question 2

Polypeptide chains in HbA2

Answer 2

Alpha 2 Delta 2

Question 3

Polypeptide Chains in HbA

Answer 3

Alpha 2 Beta 2

Question 4

Characteristics of Thalassemia Traits

Answer 4

• RBC survival is usually normal
• Microcytosis
• normal/slightly decreased Hb

Question 5

Characteristics of Thalassemia Majors (5)

Answer 5

• Ineffective erythropoiesis
  
  • Marrow tries to make RBCs which lyse
• Decreased RBC viability
  
  • excess alpha chains percipitate out as Heinz Bodies and lyse cell
• Splenomegaly
  
  • RBCs are sequestered in spleen–> enlargement
• Marrow space expansion
  
  • due to increased eryhtropoeises –> frontal bossing and long bone breaks
• Iron overload
  
  • 1) from Transfusions (treatment)
  • 2) from increased erythropoeises –> incresed Fe absorption from gut
  • Hypogonadism, pancreatic, liver, heart failure

Question 6

In what population are beta thalassemias most commonly found?

Answer 6

Mediterrainian

Question 7

Beta-Thalassemia Minor

Answer 7

• Heterozygous, have one normal beta globin allele
• Lab values
  
  • Normal Hb
  • decreased MCV (no Hb in RBCs)
  • increased RBC (to make up for lysed)
  • Smear: hypochromasia, microcytosis, target cells, basophillic stippling
  • increased HbA2 is HALLMARK

Question 8

What is the hallmark of Beta-thalassemia minor?

Answer 8

• increased HbA2

Question 9

Beta-Thalassemia Major

Answer 9

• Homozygous
• Cooley’s anemia
• unpaired alpha chains percip. out as Heinz bodies
• Effects
  
  • Severe and chronic anemia
  • chronic hemolysis
  • organ damage from Fe overload
  • increased bone marrow RBC progenitors