Sickle cell anemia

Haematopoiesis

Haemolysis

Disease

Hemoglobinopathy

Biology

Stem cell

Acute chest syndrome

Internal medicine

Immunology

Genetics

Medicine

Nature Reviews Disease Primers

Sickle cell disease (SCD) is a group of inherited disorders caused by mutations in HBB, which encodes haemoglobin subunit β. The incidence is estimated to be between 300,000 and 400,000 neonates globally each year, the majority in sub-Saharan Africa. Haemoglobin molecules that include mutant sickle β-globin subunits can polymerize; erythrocytes that contain mostly haemoglobin polymers assume a sickled form and are prone to haemolysis. Other pathophysiological mechanisms that contribute to the SCD phenotype are vaso-occlusion and activation of the immune system. SCD is characterized by a remarkable phenotypic complexity. Common acute complications are acute pain events, acute chest syndrome and stroke; chronic complications (including chronic kidney disease) can damage all organs. Hydroxycarbamide, blood transfusions and haematopoietic stem cell transplantation can reduce the severity of the disease. Early diagnosis is crucial to improve survival, and universal newborn screening programmes have been implemented in some countries but are challenging in low-income, high-burden settings. Sickle cell disease includes genetic conditions that are caused by mutations in one of the genes encoding haemoglobin. Mutant haemoglobin molecules can polymerize, causing the red blood cells to acquire a characteristic crescent shape that gives the disease its name.

Sickle cell disease