Key Takeaways

Hemoglobin (Hb) C disorders are a group of chronic, hereditary anemias characterized by presence of ≥ 1 HbC allele leading to symptomatic disease.

Hemoglobin (Hb) C disorders are divided into 2) HbC disease, which includes HbCC and a number of compound heterozygous conditions, and 2) sickle cell disease, which occurs with HbSC .

HbC is an inherited single base mutation at codon 6 of the beta-globin gene, leading to substitution of lysine for glutamic acid.

HbCC leads to Hb crystallization and red cell dehydration. The latter results in microcytic, hyperchromic red cells with reduced mean cell volume (MCV) and mean corpuscular hemoglobin concentration (MCHC).

Patients homozygous for HbC (HbCC, hemoglobin C disease) may have mild hemolytic anemia and splenomegaly, while those with HbSC present with a sickle cell disease phenotype.

Diagnosis is confirmed by hemoglobin electrophoresis.

HbCC is clinically mild/silent and does not need treatment. Patients with HbSC are treated similarly to those with HbSS.