Figure 4:

Hemoglobin alleles and degree of sickling. Most people have 2 hemoglobin (Hb) A alleles. Patients with sickle cell trait have 1 allele for either HbS (sickle cell trait) or HbC (HbC trait) and generally have a low level of sickling. The most common form of sickle cell disease involves 2 HbS alleles (HbSS). Patients with HbSC disease, like our patient, have 1 HbS allele and 1 HbC allele (HbSC). Hemoglobin C disease (2 HbC alleles) does not lead to sickling, but is characterized by hemolysis with associated anemia.¹