Hemoglobinopathies

Question 1

What is the amino acid substitution responsible for Sickle cell hemoglobin?

Answer 1

On the Hgb beta chain allele there is a valine instead of glutamic acid at position 6

Question 2

What happens to Hbg S when deoxygenated and how does this affect the body?

Answer 2

It polymerizes and concentrates, causing sickled cells that are rigid and don’t travel easily through microvasculature; they cannot then deliver O2 to tissues effectively and can obstruct small vessels; they also have shorter lifespan

Question 3

Describe lab findings of Sickle cell disease, HbgSS

Answer 3

severe anemia, incrsd reticulocytes and NRBCs, sickle (long pointed OR sickle shape!) cells, target cells, polychromasia, Ho-Jos, and Pappenheimer bodies

Question 4

What is the amino acid sub in HgCC disease?

Answer 4

Lysine for glutamic acid at position 6 of beta chain allele

Question 5

Lab findings typical of Hgb C disease? Include electrophoresis and what also migrates with it

Answer 5

mild anemia (hgb 8 to 12 g/dL), target cells, Hexagonal or rod shaped crystals in RBCs; 
90% HbC on electrophoresis: C moves with A2, E & Oarab

Question 6

What are the lab findings and pathophys of Hbg SC disease?

Answer 6

This is when a patient has both the S and C mutations so all Beta chains are abnormal.
moderate anemia with target cells, SC cells: folded/fingerlike projections all w/ precipitated hgb inside, perhaps micro-hypo-RBCs, spherocytes, schistocytes, Aniso and poikilocytosis

Question 7

How do the hemoglobins migrate at pH 8.6 on cellulose

Answer 7

A1 fastest, closest to anode; F is next fastest, then altogether SDG (think SluDGe), and finally altogether A2, C, E and O (think 2 ACE-O)

Question 8

How do the hemoglobins migrate at pH 6.2 on agar?

Answer 8

Most anodal/fastest: C & S; then A1A2DEG together, then F