Disease Facts

Sickle Cell Disease Facts

Sickle Cell Disease (SCD)

Sickle Cell Disease Overview

Approximately 100,000 people living with SCD in the United States, millions worldwide.
About 300,000 people born with SCD annually globally.
Historically received little attention and resources compared to other genetic disorders.
Only one FDA-approved drug for SCD until December 2018.
Primary affected population consists of racial and ethnic minorities.
Persistent discrimination and racism contribute to lack of awareness and resources.
Funding for SCD historically low compared to other conditions.

Lifelong Illness and Treatment

SCD is a lifelong illness.
Blood and bone marrow transplant is the only cure for SCD.

Sickle Cell Trait (SCT)

Sickle Cell Trait Overview

1-3 million Americans and 8-10 percent of African Americans in the U.S. have SCT.
Over 100 million people globally live with SCT.

Inheritance and Genetic Transmission

If both parents have SCT:
50% chance child inherits SCT.
25% chance child has SCD.
25% chance child does not have SCD or SCT.

Genotypes of SCD

Sickle Cell Disease Types

Various types of inherited disorders based on HBB gene mutations.
Hemoglobin S (HbS) is the most common abnormal hemoglobin.
Severity and symptoms vary depending on the type of SCD.

Sickle Cell Anemia (HbSS)

Most common and severe type of SCD.
Occurs when a person inherits two genes for HbS.
Causes chronic anemia, pain episodes, and organ damage.

Sickle Cell Trait (HbAS)

Occurs when a person inherits one gene for HbS and one gene for normal hemoglobin A.
Usually asymptomatic, but can pass on the HbS gene to children.
Rarely may experience pain crises.

HbSC

Inheritance of HbS gene and abnormal hemoglobin C gene.
Milder anemia and less frequent complications than sickle cell anemia.
Complications include proliferative sickle cell retinopathy and osteonecrosis.

HbS Beta-Thalassemia

Inheritance of HbS gene and beta-thalassemia gene.
Severity depends on the amount of normal hemoglobin produced.
Similar complications to sickle cell anemia.

Other Types of SCD

Less common types include HbSD, HbSE, and HbSO.
Result from inheritance of HbS gene and gene for another abnormal hemoglobin (D, E, or O).
Vary in symptoms and prevalence based on ancestral backgrounds.