Prevalence: 1/3,000 to 1/6,000 in populations of African origin (voltaic plateau in Burkina Faso).

Hemoglobinopathy due to a mutation in the β globin chain (mutation ß6 [A3] Glu ðLys) leading to the synthesis of an abnormal hemoglobin C instead of normal hemoglobin A. This anomaly is called HbC Harlem when a second mutation is present in the β chain. This results in dehydration of the red blood cells that contain this Hb, which increases their fragility.

Clinical picture:

-        subjects heterozygous for HbC (AC): asymptomatic; moderate microcytosis with increased osmotic resistance;

-        subjects homozygous for HbC (CC): compensated hemolysis  with splenomegaly and hypersplenism, biliary lithiasis, deficiency in folate, symptomatic erythroblastopenia in case of Parvovirus B19 infection;

-        association of HbC with β-Thalassemia: clinical picture similar to that of homozygosis CC;

-        subjects heterozygous composite SC (HbS and HbC): major sickle cell syndrome (less severe than in the homozygous SS form); high frequency of painful vaso-occlusive crises and acute chest syndrome; priapism; epiphyseal osteonecrosis; proliferative retinopathy, vitreous hemorrhage, retinal detachment; splenomegaly after the age of 5 years may be complicated (infarct, splenic sequestration); prevention of pneumococcal infections (vaccination) and daily penicillin until at least the age of 5 years; symptomatic treatment of painful crises; transfusion in case of poorly tolerated acute anemia (splenic sequestration, erythroblastopenia due to Parvovirus B19)

Anesthetic implications: 

for the homozygous and composite forms SC, same precautions as for sickle cell disease: avoid any hypoxemia, acidosis, hypothermia and stasis, maintain a normal heart rate. Two types of complications to fear:

-         specific: hyperalgesic vaso-occlusive crises, painful acute chest syndrome, erythrocyte alloimmunisation, transfusion reactions;

-         non-specific: thromboembolic events, bleeding, fever, severe infections.

References : 

Updated: April 2019