The Type of SCD Depends on the Mutation
Sickle Cell Traits vs SCD Genotypes1,3-6
Sickle Cell Trait

Individuals with sickle cell trait inherit 1 mutant allele (Hbs)
- ~8% of African Americans are sickle cell trait carriers1
Sickle Cell Anemia

Individuals with sickle cell anemia inherit 2 HbS alleles
- ~74%-76%* of SCD population4,5
- ~70% are of African ancestry4,5
Other SCD Genotypes

Individuals inherit 1 HbS allele and another mutant Hb allele
5 different subtypes, depending on other mutation
- HbSC represents ~18%-24% of SCD population4,5*
- ~25%-30% are of African ancestry
- HbSβ0-thalassemia represents ~1%-6% of SCD population4,5*
- Most prevalent in people of Eastern Mediterranean or Indian descent
- HbSβ+-thalassemia represents ~1%-6% of SCD population4,5*
- Most prevalent in people of Eastern Mediterranean or Indian descent
- HbSD represents 1.3% of SCD population5*
- Most prevalent in northern India but occurs worldwide
- HbSα-thalassemia6
- ~40% are of African ancestry
- ~45% are of South East Asian ancestry
*Based on 3 large multicenter cohorts of patients with SCD of predominantly African ancestry in the Americas and the United Kingdom.5