Diagnosis: Hemoglobin C trait
• Hemoglobin C is a β-chain hemoglobin variant that results from a mutation in the β-globin gene (β6Glu->Lys).
• Glutamate is a negatively charged amino acid and lysine is positively charged; which results in a +2 net gain of charge. Therefore, it migrates slower than hemoglobin A and hemoglobin S on alkaline electrophoresis.
• Hemoglobin C trait (hemoglobin A/hemoglobin C; ββC) is a clinically asymptomatic hemoglobinopathy.
• It is important to identify the presence of hemoglobin C for genetic counseling and prenatal testing. When a child inherits hemoglobin C from one parent and hemoglobin S (βS) from the other parent, the child will have the clinically significant sickling disorder hemoglobin SC disease.
• Hematologically, the hemoglobin is usually normal in hemoglobin C trait. The mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) can be normal or slightly below the reference range because of red cell dehydration. The peripheral blood smear is normal, or it can show hypochromia and microcytosis and/or target cells.