Sickle cell disease

Alternative names	Sickle cell anaemia
About the condition	Sickle cell disease is a group of inherited conditions affecting haemoglobin structure. It is caused by specific changes in the beta-globin gene (HBB), which codes for part of the protein component of haemoglobin. The abnormal haemoglobin can precipitate, causing the red cell to change shape (to a crescent or “sickle” shape) and allowing them to ‘stick’ in capillaries and small blood vessels. This impedes blood flow and oxygen supply to tissues, potentially causing severe pain, organ damage, infection, and possibly stroke. The red cells are also more fragile than normal, resulting in chronic anaemia (due to higher red cell breakdown) and jaundice. Sickle cell disease mainly impacts people of African, Middle Eastern, Indian and Mediterranean descent.
Inheritance	Autosomal recessive
Year screening started in WA	2026
Incidence in Australia	Low, currently unknown.
Defect	A specific homozygous genetic variation in the HBB genes causing sickle haemoglobin (HbSS), or a compound heterozygous state of a single HbS variant with another pathogenic variant in the HBB genes (e.g. beta thalassaemia).
Symptoms if untreated	Chronic anaemia Fatigue and weakness Pain crises (bones, abdomen) Swelling in hands and feet along with fever. Frequent infections (including risk of overwhelming sepsis) Potential life-threatening episodes including acute chest syndrome (resulting in blockage of blood flow to lungs), stroke, and chronic organ damage including renal failure, heart and lung disease
Determinants on bloodspot screening	Detection of the HBB variant encoding HbS and detection of other pathogenic HBB variants by DNA PCR and sequencing analysis
Diagnostic tests	Haemoglobin analysis and genetic HBB gene testing
Treatment	Supportive care including folic acid, antibiotics and pain relief Hydroxycarbamide Blood transfusions Exchange transfusion (removal of abnormal red cells with simultaneous administration of normal red cells via transfusion) Bone marrow transplant
Screening issues	Sickle cell trait; HbS simple heterozygotes (carriers) are not reported in bloodspot newborn screening.