
Figure 1. Sickle red blood cell.
SCD refers to all genotypes containing at least one sickle gene, in which HbS makes up at least half of the hemoglobin present. Major sickle genotypes described so far include:
HbSS disease or sickle cell anemia (the most common form): Homozygote for the S globin with usually a severe or moderately severe phenotype and with the shortest survival
HbS/b-0 thalassemia: Compound heterozygote for HbS and b-0 thalassemia; clinically indistinguishable from sickle cell anemia (SCA)
HbS/b+ thalassemia: Mild-to-moderate severity with variability in different ethnicities
HbSC disease: Compound heterozygote for HbS and HbC characterized by moderate clinical severity
HbS/hereditary persistence of fetal Hb (S/HPHP): Very mild or asymptomatic phenotype
HbS/HbE syndrome: Very rare, with a phenotype usually similar to HbS/b+ thalassemia
Rare combinations of HbS with other abnormal hemoglobins such as HbD Los Angeles, G-Philadelphia, HbO Arab, and others
Learn more about the genetics of SCD.
Medscape © 2021 WebMD, LLC
Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: Emmanuel C. Besa, Sophie M. Lanzkron. Fast Five Quiz: Are You Prepared to Confront Sickle Cell Disease? - Medscape - Sep 23, 2021.
Comments