Genetic Disorders

Sickle Cell Disease

겸상적혈구병

Abnormal hemoglobin (HbS) from HBB gene mutation

Written and edited by Dr. Kwang Lee, D.C., L.Ac. · Updated 2026-10-04

How common: 1 in 365 African ancestry
Typical age: Late infancy onset

What is it?

β-globin (HBB) codon 6 Glu→Val mutation → HbS polymerizes when deoxygenated → RBC sickling.

Commonly affected: RBCs (systemic microvascular impact)

How it develops

HBB mutation (AR)Codon 6 Glu→Val (β6E6V)
HbS polymerizationPolymerizes under hypoxia, acidosis, dehydration
Sickling + vaso-occlusionMicrovascular occlusion, chronic hemolysis
Infarction + pain + organ damageStroke, autosplenectomy, renal/lung damage

Symptoms

Vaso-occlusive pain crisisSevere bone, hand-foot, back pain
Acute chest syndromePulmonary infiltrate + fever + chest pain (emergency)
Stroke risk~11% of children have stroke
Hemolytic anemiaHb 6–9 g/dL, jaundice
AutosplenectomySplenic loss by age 6 → pneumococcal sepsis

How it is examined

Hb electrophoresisSeparates HbS, HbF (HPLC)
Peripheral smearSickle cells, target cells, Howell-Jolly bodies
Transcranial DopplerStroke risk (velocity ≥200 cm/s)

Imaging

CXR: acute chest syndrome infiltrate. Bone XR: infarcts.

Pulmonary infiltrate
Bone infarcts
H-shaped vertebrae

Brain MRI/MRA for infarcts and moyamoya.

Silent infarcts
Avascular necrosis of femoral head

Non-surgical care

HydroxyureaIncreases HbF → reduces crisis frequency
Pneumococcal vaccine + PCN ppxDaily penicillin until age 5
Folate supplementationChronic hemolysis increases folate need
Fluids + analgesia (crisis)Step-wise analgesia including opioids
Transfusion (crisis/stroke ppx)Chronic transfusion for stroke prevention

Conservative options are generally tried first. Medications listed here can have side effects — discuss them with your prescriber.

When surgery is considered

Refractory + stroke + organ damage

Procedures that may be discussed

Hematopoietic stem cell transplant - curative
Gene therapy (exa-cel, lovo-cel) - FDA approved
Cholecystectomy (gallstones)

Outlook

Mean survival now into 50s with treatment; gene therapy now curative.