What is the difference between sickle cells and healthy RBCs? 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The abnormally shaped cells are unable to perform the function of healthy RBCs efficiently. As a result, a person may experience various symptoms and complications. SCD describes a group of genetic RBC disorders that affects roughly 100,000 people in the United States. RBCs are an important component of the blood, and they are responsible for its red color. The human body produces roughly 2 million RBCs every second. RBCs have the vital role of carrying oxygen throughout the body. If they cannot perform this role due to SCD, a person may experience various complications, including anemia, severe pain, and organ damage. In this article, we discuss the differences between sickle cells and healthy RBCs. We also explain how these differences affect the function of sickle cells. How do sickle cells differ from healthy RBCs Share on PinterestMedical illustration by Bailey Mariner Illustration by Brittany EnglandSickle cells are a type of hemoglobinopathy. This term refers to conditions that alter the production or structure of hemoglobin. This iron-rich protein plays a key role in delivering oxygen around the body and provides RBCs with their shape and color. Many different types of hemoglobin exist. The most common type in healthy RBCs is hemoglobin A (HbA). This type of hemoglobin provides RBCs with a soft, round shape that allows them to pass easily through blood vessels and deliver oxygen effectively. On average, these healthy RBCs live for 120 days before the body replaces them with new ones. A person with SCD instead makes a different type of hemoglobin, which is known as hemoglobin S (HbS). This type of hemoglobin causes RBCs to distort into a C-shape, or the shape of a sickle. Unlike healthy RBCs, sickle cells only live for 10–20 days. Why do they differ The type of hemoglobin a person produces can alter the shape of their RBCs. The hemoglobin protein consists of smaller subunits, which contain two chains of alpha-globin and two chains of beta-globin. A person with SCD has a gene alteration in the HBB gene, which is present on chromosome 11. This alteration provides the body with instructions to produce HbS instead of HbA. This change replaces a single building block of protein, known as an amino acid, in beta-globin. Specifically, it replaces glutamic acid with valine. This single change causes the RBCs to have the characteristic sickle shape. How does this change in shape affect their function Healthy RBCs are round and flexible, which allows them to move easily through blood vessels and transport oxygen around the body. Due to their C-shape and rigidity, sickle cells have difficulty passing through blood vessels. As they break apart easily, clump together, and stick to the walls of blood vessels, they may block the flow of oxygen-rich blood. This clumping of red blood cells and lack of oxygen to tissue can cause severe pain, infections, and damage to the body. Doctors refer to these severe instances of pain as a sickle cell crisis. Potential complications of SCD may include: strokeacute chest syndromeorgan damage In severe cases, SCD can result in premature death. Types of sickle cell disease Everyone inherits two sets of genes that code for the production of hemoglobin — one from each parent. This is similar to how people receive the genes that determine their hair and eye color. The exact type of SCD a person has depends on what combination of genes they inherit. Statistics show that SCD genes are more common in people of African, South and Central American, Middle Eastern, Asian, Indian, and Mediterranean descent. There are several types of SCD. The most common types include:HbSS or sickle cell anemia: A person with this condition has inherited two SCD genes that both code the production of HbS. This tends to be the most severe type of SCD.HbSC: HbSC occurs when a person inherits a gene that codes for hemoglobin S and a gene that codes for another type of hemoglobin, known as hemoglobin C (HbC). This type of hemoglobin causes a similar change to HbS but changes the amino acids in a slightly different way, resulting in a milder form of the disease.Sickle cell beta-thalassemia: HbS beta-thalassemia occurs when a person inherits a gene that codes for HbS and a gene that codes for beta-thalassemia, which is another condition that affects hemoglobin.HbAS or sickle cell trait (SCT): A person with SCT has inherited only one gene for HbS, with the other gene coding for HbA. In most cases, a person with SCT does not show symptoms, but the HbS gene can pass to their children. Treatment options The treatment for SCD can involve a variety of approaches, including medications, procedures, and lifestyle changes. The following medications can help reduce SCD complications:pain relievershydroxyurea (Hydrea), which can help reduce the number of sickle cell crises by increasing the amount of fetal hemoglobin (HbF), a type of hemoglobin that sickling does not affectcrizanlizumab (Adakveo), which binds to a protein called P-selectin to prevent RBCs from sticking togethervoxelotor (Oxbryta), which tries to prevent RBCs from forming the sickle shape Several procedures also aim to reduce the severity of SCD symptoms:Blood transfusions: This option involves a person receiving blood that contains healthy RBCs from a compatible donor.Stem cell transplants: This procedure has the potential to cure SCD by replacing an individual’s cells with donor cells that are free of sickling. Gene therapy: This treatment is similar to stem cell transplants and also offers a potential cure for SCD. Rather than using a donor, doctors modify a person’s own stem cells to produce healthy RBCs. A person with SCD may be more susceptible to dangerous complications from an infection. However, they can take steps to minimize this risk. These include:washing the hands frequentlyreceiving vaccinations, including the flu vaccinationavoiding handling reptiles such as turtles, snakes, and lizards, as they carry Salmonellaexcluding raw eggs and unpasteurized dairy products from the dietcooking meat thoroughly before eating it Summary Sickle cell disease refers to a group of genetic conditions that affect the type of hemoglobin a person’s body produces. Different types of hemoglobin affect both the shape and function of red blood cells. This can lead to a person experiencing a variety of symptoms and health complications. Treatments are available to minimize the effects of sickle cell disease and encourage the production of healthy red blood cells. Last medically reviewed on August 26, 2022GeneticsVascularBiology / BiochemistryBlood / Hematologysickle cell disease 24 sourcescollapsedMedical News Today has strict sourcing guidelines and draws only from peer-reviewed studies, academic research institutions, and medical journals and associations. We avoid using tertiary references. We link primary sources — including studies, scientific references, and statistics — within each article and also list them in the resources section at the bottom of our articles. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.About sickle cell disease. (2020). https://www.genome.gov/Genetic-Disorders/Sickle-Cell-DiseaseAshorobi, D., et al. (2022). Bone marrow transplantation in sickle cell disease. https://www.ncbi.nlm.nih.gov/books/NBK538515/Blood basics. (n.d.). https://www.hematology.org/education/patients/blood-basicsBorhade, M. B., et al. (2021). Sickle cell crisis. https://www.ncbi.nlm.nih.gov/books/NBK526064/de Guarda, C. C., et al. (2020). Sickle cell disease: A distinction of two most frequent genotypes (HbSS and HbSC). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6988974/Gene therapy program: SCD. (n.d.). https://www.childrenshospital.org/programs/gene-therapy-program/conditions-we-treat/scdHaemoglobinopathy evaluation. (2018). https://labtestsonline.org.uk/tests/haemoglobinopathy-evaluationHBB gene. (2020). https://medlineplus.gov/genetics/gene/hbb/Hemoglobin electrophoresis. (2021). https://medlineplus.gov/lab-tests/hemoglobin-electrophoresis/Hemoglobin S. (n.d.). https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=167&contentid=hemoglobin_sHemoglobinopathies: Current practices for screening, confirmation and follow-up. (2015). https://www.cdc.gov/ncbddd/sicklecell/documents/nbs_hemoglobinopathy-testing_122015.pdfHow your body replaces blood. (n.d.). https://www.blood.co.uk/the-donation-process/after-your-donation/how-your-body-replaces-blood/Hydroxyurea for sickle cell disease. (n.d.). https://www.hematology.org/-/media/Hematology/Files/Education/Hydroxyurea-Booklet.pdfKaufman, D. P., et al. (2022). Physiology, fetal hemoglobin. https://www.ncbi.nlm.nih.gov/books/NBK500011/Red blood cells and why they are important. (n.d.). https://www.redcrossblood.org/donate-blood/dlp/red-blood-cells.htmlSickle cell disease. (2020). https://medlineplus.gov/genetics/condition/sickle-cell-disease/Sickle cell disease. (n.d.). https://www.hematology.org/education/patients/anemia/sickle-cell-diseaseSickle cell disease. (n.d.). https://www.hopkinsmedicine.org/health/conditions-and-diseases/sickle-cell-diseaseSickle cell disease (SCD). (2022). https://www.cdc.gov/ncbddd/sicklecell/index.htmlSickle cell disease: Treatment. (2022). https://www.nhlbi.nih.gov/health/sickle-cell-disease/treatmentUnderstanding haemoglobinopathies. (2018). https://www.gov.uk/government/publications/handbook-for-sickle-cell-and-thalassaemia-screening/understanding-haemoglobinopathiesWhat is inheritance? (2021). https://www.yourgenome.org/facts/what-is-inheritance/What is sickle cell disease? (n.d.). http://www.scdcoalition.org/pdfs/ASH_Infographic.pdfWhat is sickle cell disease (SCD)? (n.d.).https://www.sicklecelldisease.org/sickle-cell-health-and-disease/types/FEEDBACK:Medically reviewed by Angelica Balingit, MD — By Flynn Williams on August 26, 2022 Latest newsWhat sets 'SuperAgers' apart? Their unusually large neuronsOmega-3 may provide a brain boost for people in midlifeSeasonal affective disorder (SAD): How to beat it this fall and winterCDC: Monkeypox in the US 'unlikely to be eliminated in the near future'Why are more women prone to Alzheimer's? New clues arise Related CoverageIs gene therapy an option to treat sickle cell disease? What is gene therapy, and can it help treat sickle cell disease? 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