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Sickle cell disease (SCD) is a group of inherited red blood cell disorders. Red blood cells contain hemoglobin, a protein that carries oxygen. Healthy red blood cells are round, and they move through small blood vessels to carry oxygen to all parts of the body. In someone who has SCD, the hemoglobin is abnormal, which causes the red blood cells to become hard and sticky and look like a C-shaped farm tool called a “sickle.” The sickle cells die early, which causes a constant shortage of red blood cells. Also, when they travel through small blood vessels, they get stuck and clog the blood flow. This can cause pain and other serious complications (health problems) such as infection, acute chest syndrome and stroke. Types of SCDThere are several types of SCD. The specific type of SCD a person has depends on the genes they inherited from their parents. People with SCD inherit genes that contain instructions, or code, for abnormal hemoglobin. Below are the most common types of SCD:HbSSPeople who have this form of SCD inherit two genes, one from each parent, that code for hemoglobin “S.” Hemoglobin S is an abnormal form of hemoglobin that causes the red cells to become rigid, and sickle shaped. This is commonly called sickle cell anemia and is usually the most severe form of the disease. HbSCPeople who have this form of SCD inherit a hemoglobin “S” gene from one parent and a gene for a different type of abnormal hemoglobin called “C” from the other parent. This is usually a milder form of SCD. HbS beta thalassemiaPeople who have this form of SCD inherit a hemoglobin “S” gene from one parent and a gene for beta thalassemia, another type of hemoglobin abnormality, from the other parent. There are two types of beta thalassemia: “zero” (HbS beta0) and “plus” (HbS beta+). Those with HbS beta0-thalassemia usually have a severe form of SCD. People with HbS beta+-thalassemia tend to have a milder form of SCD. There also are a few rare types of SCD, such as the following:HbSD, HbSE, and HbSOPeople who have these forms of SCD inherit one hemoglobin “S” gene and one gene that codes for another abnormal type of hemoglobin (“D”, “E”, or “O”). The severity of these rarer types of SCD varies. Sickle Cell Trait (SCT)HbASPeople who have sickle cell trait (SCT) inherit a hemoglobin “S” gene from one parent and a normal gene (one that codes for hemoglobin “A”) from the other parent. People with SCT usually do not have any of the signs of the disease. However, in rare cases, a person with SCT may develop health problems; this occurs most often when there are other stresses on the body, such as when a person becomes dehydrated or exercises strenuously. Additionally, people who have SCT can pass the abnormal hemoglobin “S” gene on to their children. Learn more about sickle cell trait » Cause of SCDSCD is a genetic condition that is present at birth. It is inherited when a child receives two genes—one from each parent—that code for abnormal hemoglobin. DiagnosisSCD is diagnosed with a simple blood test. In children born in the United States, it most often is found at birth during routine newborn screening tests at the hospital. In addition, SCD can be diagnosed while the baby is in the womb. Diagnostic tests before the baby is born, such as chorionic villus sampling and amniocentesis, can check for chromosomal or genetic abnormalities in the baby. Chorionic villus sampling tests a tiny piece of the placenta, called chorionic villus. Amniocentesis tests a small sample of amniotic fluid surrounding the baby. Because children with SCD are at an increased risk of infection and other health problems, early diagnosis and treatment are important. Talk to your doctor to find out how to get tested and to explain the results after testing. ComplicationsPeople with SCD may start to have signs of the disease during the first year of life, usually around 5 months of age. Symptoms and complications of SCD are different for each person and can range from mild to severe. Learn about the complications. Prevention and Treatment of SCD ComplicationsGeneral Prevention Strategies Management of SCD is focused on preventing and treating pain episodes and other complications. Prevention strategies include lifestyle behaviors as well as medical screening and interventions to prevent SCD complications. Lifestyle Behaviors There are simple steps that people with SCD can take to help prevent and reduce the occurrence of pain crises, including the following:
Simple steps to prevent harmful infections include the following:
Medical Screenings & Interventions to Prevent SCD Complications Prevention of Infections
Prevention of Vision Loss
Prevention of Stroke
Prevention of Severe Anemia
Management of Pain Crises When pain crises do occur, clinical management may include the following:
Specific Treatments to Prevent SCD Complications SCD is a disease that worsens over time. Treatments are available that can prevent complications and lengthen the lives of those who have this condition. These treatment options and their effects can be different for each person, depending on the symptoms and severity of their disease. It is important to understand the benefits and risks of each treatment option. Currently, the FDA has approved four treatments for SCD[1].
Several other treatments and therapies for SCD have recently been developed that are still undergoing clinical trials and thus have not yet been approved by the FDA. CureThe only therapy approved by the FDA that may be able to cure SCD is a bone marrow or stem cell transplant. Bone marrow is a soft, fatty tissue inside the center of the bones, where blood cells are made. A bone marrow or stem cell transplant is a procedure that takes healthy cells that form blood from one person—the donor—and puts them into someone whose bone marrow is not working properly. Bone marrow or stem cell transplants are very risky and can have serious side effects, including death. For the transplant to work, the bone marrow must be a close match. Usually, the best donor is a brother or sister. Bone marrow or stem cell transplants are most common in cases of severe SCD for children who have minimal organ damage from the disease. Find clinical treatment guidelines for providers as well as patient and family resources derived from clinical treatment guidelines:For Healthcare Providers
For People with SCD and their Families
[1] CDC will periodically review and update this treatment list when new treatments are approved by the FDA. How does thalassemia differ from sickle cell anemia?The main difference between sickle cell anaemia and thalassemia is that thalassemia can affect both and globin chains, whereas sickle cell anaemia affects just the globin chains. Anaemia is a disorder in which your body lacks enough normal, healthy red blood cells to function properly.
What type of anemia is sickle cell and thalassemia?Sickle cell beta-thalassemia is a type of RBC disorder known as a hemoglobinopathy . These are conditions that cause abnormal hemoglobin production or a change in its structure. Hemoglobin is the protein in RBCs responsible for carrying oxygen around the body.
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