42 Hemoglobin C (Hb CC) Disease

Michelle To and Valentin Villatoro

Cause(s): 

β globin chain amino acid substitution in the 6th position from glutamic acid (Glu) to lysine (Lys).1,2

 

Inheritance:

Autosomal dominant1

 

Demographics: 

West Africa1

 

Clinical Features:1-3

See Hemoglobin C under RBC inclusions for additional information.

Less splenic sequestration and milder chronic hemolysis compared to sickle cell disease. Patients are usually asymptomatic.

 

Laboratory Features:1,2

CBC:

Hb: Decreased

Hct: Decreased

PBS:

Normochromic, normocytic RBCs

*Hb C crystals

Target cells

nRBCs

BM:

N/A

Hemoglobin Electrophoresis:

Hb S: >90

Hb A: None

Hb A2: Normal

Hb F: <7%

 

*Not always seen, more likely in patients who have had a splenectomy.

Other Tests:

Solubility Screen: Negative

Metasulfite Sickling Test: Negative

HPLC

Hemoglobin Electrophoresis


References:

1. Laudicina RJ. Hemoglobinopathies: qualitative defects. In: Clinical laboratory hematology. 3rd ed. New Jersey: Pearson; 2015. p.231–50.

2. Randolph TR. Hemoglobinopathies (structural defects in hemoglobin). In: Rodak’s hematology clinical applications and principles. 5th ed. St. Louis, Missouri: Saunders; 2015. p. 426-453.

3. Harmening DM, Yang D, Zeringer H. Hemolytic anemias: intracorpuscular defects. 5th ed. Philadelphia: F.A. Davis Company; 2009. p. 207-29).

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A Laboratory Guide to Clinical Hematology by Michelle To and Valentin Villatoro is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.

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