Thalassemia Flashcards
Alpha thalassemia
defect (deletion) of ALPHA globulin gene so no normal hemoglobulin chains of 2A and 2B.
autosomal recessive
seen in Asians and African populations
single alpha gene mutation results in
alpha thalassemia minor.
clinically silent carriers no dx
two alpha gene mutation results in
alpha thalassemia trait
mild anemia and more fatigability
Hgb 10 and see low MCV
they will have normal iron stores
normal hemoglobulin electrophoresis
three gene mutation of alpha thalassemia is
Hemoglobin H disease
more severe anemia Hgb of 7-8
- tetramere of beta globulin called hemoglobin H
only one alpha globulin for the 3 beta globulin
how to diagnose alpha thalassemia?
can screen with a hemoglobin electrophoresis confirmation is with genetic testing
Hgb H disease is
three alpha mutation alpha thalassemia
has Hgb of 7-8 but seldom transfusion dependent
danger with giving iron to Hgb H dx alpha thalassemia
need to avoid giving iron supplements can have iron overload if they have heart and liver failure. need iron chelation therapy with IV desferrioxamine or oral iron chelators (deferiprone or defersirox)
what do alpha thalassemia trait (2 gene) pts need to get?
need to get genetic counseling
what should all patients with alpha thalassemia get?
folate supplementation.
beta thalassemia is
autosomal recessive mutation on chromosome 11
decreased or no production of beta globulin.
seen in Mediterrean, Asian, and Africans
three types of beta thalassemia
beta thalassemia - the beta gene mutation codes for either reduced or no beta globulin so see three spectrums of dx:
minor - 1 mutation resulting in one either reduced beta globulin. Asymptomatic
intermedia - 2 beta globulin genes are reduced, see more hgbF
major- no beta globulin is made. seen only after 6 months of life as there is HgbF. some people can have some production after 6 months of life.
electrophoresis of beta thalassemia
consequences of beta thalassemia major
consequence of this is the alpha chains clump together and damage the RBC membranes which Hemoglobulin Alpha congreate and cause damage to the RBC membrane which leads to hemolysis and anemia. Can also see splenomegaly as the macrophages eat at damaged RBCs in spleen.
see elevated conjugated bilirubin and see iron overload as extra iron is taken in
can see hypoxia - see bone marrow and extramedullary production of RBCs.
Beta thalassemia intermedia and major will have
Hgb A2 - two alpha and two delta globulins since there’s less beta globulin made
