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SCD is a group of autosomal recessive disorders characterised by the predominance of HbS that results in the production of abnormal RBCs. Due to mutations of the beta-globin gene,1 Hb are ‘sickle’ shaped and inflexible; this can increase blood viscosity and block or limit blood flow to the limbs and organs.2
SCD is most common in people living or originating from sub-Saharan Africa, but also affects people of Mediterranean, Caribbean, Middle-Eastern and Asian origin. The WHO estimates that 220,000 babies in Africa are born with SCD every year, many of whom die before the age of 5 years. In the UK, SCD is the most common serious genetic disorder and affects over 1 in 2,000 live births.3
SCD is commonly expressed in patients in different forms:
SCD is a multi-system disease with unpredictable acute and chronic components, including:
SCD increases the risk of stroke, organ damage, bacterial infections, and complications of blood transfusion. As a result, SCD is associated with lifelong morbidity and a reduced life expectancy, especially in young children. About 10% of children with HbS may develop a stroke, and more than 50% of these may suffer recurrent strokes.3
SCD and the risk of iron overload
Frequent blood transfusions are recommended to help treat SCD-associated complications (most notably anaemia), predisposing SCD patients to iron overload.4–6
Abbreviations: HbS, sickle haemoglobin; RBC, red blood cell; SCD, sickle cell disease; WHO, World Health Organization.
References
- Quinn CT. Clinical severity in sickle cell disease: the challenges of definition and prognostication. Exp Biol Med (Maywood). 2016;241(7):679–688.
- Yawn BP and John-Sowah J. Management of sickle cell disease: recommendations from the 2014 Expert Panel report. Am Fam Physician. 2015;92(12):1069–1076.
- Meremikwu MM and Okomo U. Sickle cell disease. BMJ Clin Evid 2016:01:2402.
- McCavit T and Desai P. National Heart, Lung and Blood Institute. 2014. Available at: www.hematology.org/Clinicians/Guidelines-Quality/Quick-Ref/3466.aspx. Last accessed February 2020.
- Claster S and Vichinsky EP. Managing sickle cell disease. BMJ 2003;327:1151–1155.
- Davis BA, et al. Guidelines on red cell transfusion in sickle cell disease. BJH 2017;176:179–191.
