Unit 5: Hemoglobin Disorders

What is the structure of hemoglobin?

4 globin chains

4 heme groups

What 4 things is hemoglobin made of?

1. iron (in heme)

2. protoporphyrin IX ring (in heme)

3. polypeptide chains (in globin)

4. amino acids (in globin)

95-98% of total hemoglobin in a healthy patient is Hg __.

A

What is the structure of Hg A?

2 alpha chains + 2 beta chains

2-3% of total hemoglobin in a healthy patient is Hg __.

A2

What is the structure of Hg A2?

2 alpha chains + 2 delta chains

< 1% of total hemoglobin in a healthy patient is Hg __.

F

What is the structure of Hg F?

2 alpha chains + 2 gamma chains

Hemoglobinopathies are (qualitative/quantitative) disorders that alter amino acid sequences in hemoglobin. What is one example?

qualitative

Sickle Cell

Sickle cell anemia is caused by ______ replacing glutamic acid in the beta chain.

valine

Sickle cell anemia causes low oxygen due to irregularly shaped RBCs. This can lead to splenic dysfunction, causing what RBC inclusions to form?

Howell-Jolly bodies

Sickled RBCs adhering to the vascular endothelium is called:

vasoocclusion

An alkaline envronement of 8.4-8.6 will cause hemoglobins to travel away from the _______ and move towards the ________.

cathode

anode

What is the normal hemoglobin electrophoresis pattern?

cathode -

crawl - Hg C, A2, E

slow - Hg S, D

fast - Hg F

accelerate - Hg A

anode +

What screening is used to detect Hg F?

Kleihauer-Betke

What screening is used to detect Hg S?

dithionite solubility

Thalassemias are (qualitative/quantitative) disorders that cause a decreased synthesis of globin chains.

quantitative

Are alpha or beta thalassemias more severe?

alpha

What is a common RBC shape you’ll see in thalassemias?

codocytes

What type of anemia are thalassemias?

microcytic, hypochromic

What is the most common screening test for hereditary spherocytosis?

osmotic fragility

An increase in hemoglobin A₂ may be indicative of beta thalassemia (major/minor).

minor

Hemoglobin H disease results from an absence of ___ of the 4 alpha genes.

3

Which hemoglobin is resistant to alkali denaturation and acid elution?

Hg F

Hemoglobin affinity for oxygen is regulated by:

2,3-DPG