Words to know: Sickle cell disease
- Hemoglobin
- The protein in red blood cells that carries oxygen.
- Hemoglobin S
- The sickle form of hemoglobin that makes red cells stiff and curved when oxygen is low.
- Fetal hemoglobin (HbF)
- A type of hemoglobin made before birth that helps block sickling.
- Sickle cell trait
- Having one sickle gene and one normal gene. It is not a disease.
- Anemia
- Too few red blood cells, which can cause tiredness and shortness of breath.
- Hemolysis
- The early breakdown of red blood cells.
- Vaso-occlusive crisis (pain crisis)
- Sudden pain caused by sickled cells blocking blood flow.
- Acute chest syndrome
- A serious lung problem in sickle cell disease with chest pain, fever, or trouble breathing.
- Spleen
- An organ in the upper left belly that filters blood and helps fight infection.
- Splenic sequestration
- When the spleen suddenly traps a lot of blood, causing a fast drop in hemoglobin. It is an emergency.
- Priapism
- A painful erection that will not go away. It needs urgent care.
- Transcranial Doppler (TCD)
- An ultrasound that measures blood flow in the brain to check stroke risk.
- Silent stroke
- A small stroke with no obvious symptoms that can still affect thinking and learning.
- Reticulocyte
- A young red blood cell. The count shows how fast the marrow is making new red cells.
- Hydroxyurea
- A daily pill that raises fetal hemoglobin and lowers sickling.
- Exchange transfusion
- Removing sickle blood and replacing it with donor blood.
- Iron overload
- Too much iron in the body, often from many transfusions.
- Iron chelation
- Medicine that removes extra iron from the body.
- Gene therapy
- Treatment that changes or adds genes in your own stem cells to treat a disease.
- CRISPR
- A tool that can edit genes very precisely. It is used in exa-cel.
- Stem cell transplant
- Replacing your blood-making cells with healthy ones from a donor.
- Avascular necrosis
- Bone damage, often in the hip, caused by poor blood flow.
- Pulmonary hypertension
- High blood pressure in the blood vessels of the lungs.
Last updated: 2026-10-27. Medically reviewed by Veli Bakalov, MD, medical oncologist (October 2026). General education from Step by Step, the patient portal of HemeOncBuddy.