Hemoglobinopathies Flashcards
(27 cards)
What globin chains are hemoglobin A composed of?
2 beta and 2 alpha chains
What is Hgb A2 composed of?
Two alpha chains and 2 delta chains
What is Hgb F composed of?
Two alpha and 2 gamma chains.
What are the clinical and laboratory features of Beta thalassemia trait?
+/- mild anemia with no symptoms, elevated Hgb A2>3.5, microcytosis, hypochromia, target cells.
What do you find on electrophoresis for beta thalassemia trait?
Hgb A2>3.5% (3.5-8) and Hgb F 1-2%.
What do you find on electrophoresis for beta thalassemia intermedia (Hgb F value)?
Hgb F will be much higher (30-75%). Hgb A2 will be higher than what you see in Minor Dx
What do you find on electrophoresis in beta thalassemia major (Hgb F)?
Hbg F>95%. There is 0 Hbg A.
What infection can happen as a result of chelator therapy?
Yersinia infection
What are some general side effects of chelator therapy?
Growth retardation, skin reaction, cytopenias, GI side effects, hepatic/renal abnormalities, hearing/vision issues.
What is the mechanism of action with Luspatacerpt?
It binds TGF beta superligand that binds to activin causing a ligand trap and increased late stage erythropoiesis.
What complication should you be mindful of if using Luspatacerpt in those with splenectomy?
Increased thrombosis
What is hemoglobin barts?
4 gamma chains in alpha thalassemia
What is hemoglobin H?
4 beta chains in alpha thalassemia
What are the clinical and laboratory differences between alpha silent carrier and alpha trait?
Alpha silent carrier-normal to very mild anemia, no morphological abnormalities, very mildly low MCV
Alpha Trait-mild anemia/microcytosis with no symptoms, target cells/hypochromia
For both alpha silent carrier and alpha trait what are the results of the Hgb electrophoresis?
In both conditions the Hgb A2 concentration will be normal.
Summarize the key clinical features of Hemoglobin H disease
Splenomegaly, moderate anemia, high reticulocyte, hypochromia, very variable Red cell size/shape
Will Hemoglobin H patients typically require transfusions?
No they generally do not require transfusions. Unless they need a surgery or for instance develop a severe infection (situational).
What is the MCV in constant spring?
The MCV will be normal!
In hemoglobin M disease what is the principal pathology present?
The iron in hemoglobin is oxidized Fe+3 (ferric state) from Fe+2 and thus is unable to bind oxygen. This causes a functional anemia.
When hemoglobin variants have a high O2 affinity what happens to the O2 dissociation curve?
It shifts to the left.
For alpha thalassemia trait which population carries the cis configuration vs the trans configuration?
African American/mediterranean-trans configuration (-,a)(-,a)
Asian, cis-(-,-) (a,a)
What is the genotype for Hemoglobin Constant Spring?
(–/aCS,a)
What type clinical severity of symptoms do you expect from Hemoglobin Constant Spring?
These patients have much more significant anemia/splenomegaly and symptoms compared to hemoglobin H disease. These patients more often will require intermittent transfusion support compared to Hgb H disease.
How does Hemoglobin E carriers present clinically and homozygotes present? What is the MCV? What causes them to have symptoms?
Carriers are silent and have no symptoms at all w/low MCV. Homozygotes are also asymptomatic (unless they have co-inheritance of Beta or alpha thal).
