Sickle cell disease (SCD) and its variants are genetic disorders resulting from the presence of a mutated form of hemoglobin, hemoglobin S (HbS).
The most common form of SCD found in North America is homozygous HbS disease (HbSS), an autosomal recessive disorder first described by Herrick in 1910.
SCD causes significant morbidity and mortality, particularly in people of African and Mediterranean ancestry.
Morbidity, frequency of crisis, degree of anemia, and the organ systems involved vary considerably from individual to individual.
