Especially found in the Balkans, North Africa, Saudi Arabia, Sudan, and the West Indies. Hemoglobin abnormality due to the replacement of Glu by Lys in 121 in the β chain of hemoglobin (autosomal dominant transmission).

-  heterozygous form:         moderate anemia (7-9 g/dL) with normocytosis and reticulocytosis. At electrophoresis of hemoglobin Hb O Arab: 45-50 %, HbA2: 2-3 %;  association with the HbS trait results in severe sickle cell syndrome (see drepanocytosis)

-  homozygous form:         paucisymptomatic; chronic microcytic and hemolytic anemia; > 95 % HbO at electrophoresis

Anesthetic implications: 

check hemoglobin level and for a possible association with the sickle cell trait

References : 

Updated: October 2021