let's recode the building blocks
sickle cell disease
Sickle cell disease (SCD) is a serious, progressive, lifelong genetic disease caused by a single mutation in the HBB gene that leads to production of sickled hemoglobin (HbS).i
Typically, red blood cells are flexible and round allowing them to move easily through blood vessels. Sickling is when the hemoglobin inside red blood cells sticks or clumps together, causing the cell to become fragile, rigid, and crescent—or sickle—shaped and making movement through blood vessels difficult.i
What are the symptoms?
The blockages caused by sickled red blood cells can lead to the damaging of blood vessels and organs associated with the signs and symptoms associated with sickle cell. This can include painful and often unpredictable vaso-occlusive crises, anemia, and other acute and chronic complications.ii,iii,iv Over time, these symptoms and complications can lead to progressive organ damage including organ failure and even death.v,vi
How is it diagnosed?
A doctor can diagnose sickle cell disease based on the results from various screening tests, including a blood test for the presence of abnormal sickle hemoglobin.vii,viii
SCD may be diagnosed at birth as enabled by national newborn screening programs in the U.S. and UK, regional newborn screening programs in Italy and Germany, and targeted screening of at-risk births in France.ix,x
What are the clinical complications of SCD?
Sickled hemoglobin tends to stick together, causing red blood cells to take on a characteristic sickle shape, become sticky and inflexible, and have a shorter lifespan. This results in severe anemia, blockage of blood vessels and progressive damage to the blood vessel walls (called vasculopathy).i,ii,iii,iv
Over time, SCD can lead to complications such as infections, delayed growth and unpredictable episodes of vaso-occlusive events (VOEs) such as acute pain, priapism, acute chest syndrome (a condition characterized by chest pain, cough, fever, low oxygen level and breathing problems), stroke and organ failure that can lead to sudden death.xi,xii,v,vi
The severity of SCD complications varies.xiii Most children who have sickle cell disease can be pain-free between crises.xiv But adolescents and adults may also suffer from chronic, ongoing pain. Pain onset is sudden and unpredictable in individuals with SCD. It can be triggered by stress, illness, dehydration, temperature changes, wind speed, altitude, and barometric pressure, but often there is no detected factor. Chronic complications increase in prevalence and severity with age, with some beginning in childhood.xv,xvi,xvii
Resulting complications of acute complications, vasculopathy and end-organ damage can lead to pulmonary hypertension, renal failure and early death; in the U.S. the median age of death for someone with sickle cell disease is 43 - 46 years.xviii
How common is sickle cell disease?
Worldwide, there are approximately 300,000–400,000 new births of individuals with SCD annually.i,xix
Incidence and prevalence of SCD are geographically variable, with the majority of cases occurring in sub-Saharan Africa, India, Middle East, Caribbean, South America, and the Mediterranean.xix,xx
In the United States, it is estimated that sickle cell disease:
- Affects approximately 100,000 Americans.xxi,xxii
- Occurs among about 1 out of every 365 Black or African-American births.xxii
- Occurs among about 1 out of every 16,300 Hispanic-American births.xxii
Find out more.
You can find more information about sickle cell disease by visiting patient resources.
iKato GJ, Piel FB, Reid CD, et al. Sickle cell disease. Nat Rev Dis Primers. 2018;4:18010. iiLi X, Dao M, Lykotrafitis G, Karniadakis GE. Biomechanics and biorheology of red blood cells in sickle cell anemia. J Biomech. 2017;50:34-41. iiiConran N, Belcher JD. Inflammation in sickle cell disease. Clin Hemorheol Microcirc. 2018;68(2-3):263-299. ivBrousse V, Colin Y, Pereira C, et al. Erythroid adhesion molecules in sickle cell anaemia infants: insights into early pathophysiology. EBioMedicine. 2015;2(2):154-157. vChaturvedi S, Ghafuri DL, Jordan N, Kassim A, Rodeghier M, DeBaun MR. Clustering of end-organ disease and early mortality in adults with sickle cell disease: A retrospective-prospective cohort study. Am J Hematol. 2018;93(9):1153-1160. viPowars DR, Chan LS, Hiti A, Ramicone E, Johnson C. Outcome of sickle cell anemia: a 4-decade observational study of 1056 patients. Medicine (Baltimore). 2005;84(6):363-376. https://www.ncbi.nlm.nih.gov/pubmed/16267411. Accessed March 2021. viiUS Preventive Services Task Force. Screening for sickle cell disease in newborns: recommendation statement. American Family Physician. 2008;77(9):1300-1302. viiiStreetly A, Sisodia R, Dick M, Latinovic R, Hounsell K, Dormandy E. Evaluation of newborn sickle cell screening programme in England: 2010-2016. Arch Dis Child. 2018;103(7):648-653. ixColombatti R, Martella M, Cattaneo L, et al. Results of a multicenter universal newborn screening program for sickle cell disease in Italy: A call to action. Pediatr Blood Cancer. 2019:e27657. xKunz JB, Awad S, Happich M, et al. Significant prevalence of sickle cell disease in Southwest Germany: results from a birth cohort study indicate the necessity for newborn screening. Ann Hematol. 2016;95(3):397-402. xiBallas SK, et al. Sickle cell pain: a critical reappraisal. Blood. (2012) 120 (18): 3647–3656. xiiDarbari DS, Kple Faget P, Kwagyan J, Rana S, Gordeuk VR, Castro O. Circumstances of death in adult sickle cell disease patients. Am J Hematol. 2006;81(11):858 863. xiiiPace BS, Goodman SR. Sickle cell disease severity: an introduction. Exp Biol Med (Maywood). 2016;241(7):677-678. xivSmith WR, Penberthy LT, Bovbjerg VE, et al. Daily assessment of pain in adults with sickle cell disease. Ann Intern Med. 2008;148(2):94 101. xvBrandow AM, Zappia KJ, Stucky CL. Sickle cell disease: a natural model of acute and chronic pain. Pain. 2017;158 Suppl 1:S79-S84. xviNHLBI. Sickle cell Disease. https://www.nhlbi.nih.gov/health-topics/sickle-cell-disease. Accessed March 2021. Page updated September 1, 2020. xviiPiel FB, Steinberg MH, Rees DC. Sickle Cell Disease. N EnglJ Med. 2017;376(16):1561-1573. xviiiPayne AB, Mehal JM, Chapman C, Haberling DL, Richardson LC, Bean CJ, Hooper WC. Trends in sickle cell disease-related mortality in the United States, 1979-2017. Annals of Emergency Medicine. 2020; 76 (3S):S28-S36. xixPiel FB, Patil AP, Howes RE, et al. Global epidemiology of sickle haemoglobin in neonates: a contemporary geostatistical model-based map and population estimates. Lancet. 2013;381(9861):142-151. xxPiel FB, Patil AP, Howes RE, et al. Global distribution of the sickle cell gene and geographical confirmation of the malaria hypothesis. Nat Commun. 2010;1:104. xxiHassell KL. Population estimates of sickle cell disease in the U.S. Am J Prev Med. 2010;38(4 Suppl):S512 521. xxiiCenters for Disease Control and Prevention. Data & Statistics on Sickle Cell Disease. Page last reviewed: December 2020. Available at https://www.cdc.gov/ncbddd/sicklecell/data.html. Accessed March 2021.