Pathology of Anemia II Flashcards
What is thalassemia?
Group of genetic disorders characterized by the lack, or decreased synthesis, of either alpha or beta-globin chains of hemoglobin A
What is alpha thalassemia?
– alpha-thalassemia - globin chain synthesis is reduced
What is beta thalassemia?
– beta-thalassemia - -globin chain synthesis is absent or reduced
What are some consequences of thalassemia?
– low intracellular hemoglobin (hypochromia)
– relative excess of other chain
What are the 4 types of alpha thalassemia?
- Silent carrier -a/aa
- α-thalassemia trait
- -/aa (Asian)
- a/-a (black African)
- HbH disease –/-a
- Hydropsfetalis –/–
ß˚-thalassemia
It refers to lack of ß-globin expression
ß+-thalassemia
It refers to decreased ß-globin expression
How does ß-thalassemia cause anemia?
– reduced synthesis of -globin leading to inadequate HbA formation
– hemolytic component of the disease due to relative excess of -globin chains
Thalassemia Major
Clinical term to describe severe disease, reliance on transfusions
Thalassemia Minor
Clinical term to describe patients with asymptomatic, mild or absent anemia, some RBC abnormalities
What can be seen in the skull of ß-thalassemia patients?
Crew cut - expansion of marrow in the skull trying to
produce RBCs in beta thalassemia major
What do target cells in the smear indicate?
ß-thalassmia Minor
What is the only acquired defect in the RBC membrane?
Paroxysmal Nocturnal Hemoglobinuria
What is the change in Paroxysmal Nocturnal Hemoglobinuria?
Stem cell disorder that results from a mutation in the phosphatidylinositol glycan A (PIGA) gene which results in a deficiency of the GPI anchor
What are some important GPI proteins and what are they functions?
– CD55 (decay-accelerating factor)
– CD59 (membrane inhibitor of reactive lysis)
– C8 binding protein
These proteins are involved in inactivating or the complement pathway - leads to unchecked activation and RBC destruction
