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.