What is Sickle Cell Disease?
Sickle Cell Disease is a group of multiple inherited red blood cell disorders. Those who have Sickle Cell Disease or Sickle Cell Trait are at a higher risk of developing RMC then those without the disorder. In normal individuals, healthy red blood cells are round and move easily through the circulatory system to carry oxygen to all parts of the body. In people with Sickle Cell Disease, the red blood cells become hard and sticky. These sickled cells die prematurely, which causes a constant shortage of red blood cells. Also, when sickled red blood cells travel through extremely small blood vessels, they get stuck and cut off blood flow. This can cause pain and other serious problems such as infection and stroke.
Types of Sickle Cell Hemoglobinopathies
Sickle Cell Anemia
HbSS
A form of Sickle Cell Disease where a person inherits one substitution of the beta-globin gene (the sickle cell gene) from each parent. If this happens then the child has Sickle Cell Anemia (SS). Populations that have a high rate of Sickle Cell Anemia are those of African and Indian descent, as these sickled cells provide protection from Malaria.
Sickle Beta Thalassemia (SB)
People who have Sickle Beta Thalassemia (SB) disease also contain substitutions in both beta-globin genes. The severity of the disease varies according to the amount of normal beta-globin produced compared to the amount of deformed beta-globin. When no beta-globin is produced, the symptoms are almost identical to sickle cell anemia, with severe cases needing chronic blood transfusions. Populations that have a high frequency of Sickle Beta Thalassemia are those of Mediterranean and Caribbean descents.
Sickle Hemoglobin-C Disease (SC)
People with Sickle Hemoglobin-C Disease (SC) have a slightly different substitution in their beta- globin genes that produces both hemoglobin C and hemoglobin S. Sickle Hemoglobin-C disease may cause similar symptoms as sickle cell anemia but less anemia due to a higher blood count level. Populations that have a high frequency of Sickle Hemoglobin-C disease are those of West African, Mediterranean and Middle Eastern descents.
People who have SCT inherit one sickle cell gene (S) from one parent and one normal gene (A) from the other parent. This is known as Sickle Cell Trait (SCT). People with SCT usually do not have any of the signs of the disease and live a normal life, but they can pass the trait on to their children. Additionally there are a few rare health problems that may potentially be related to Sickle Cell Trait, such as RMC.
Sickle Cell Trait (SCT)
HbAS
Complications and Treatments
Common Complications Of Sickle Cell Disease
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Anemia: Sickle cells break apart easily and die, leaving you with very low levels of red blood cells. Red blood cells usually live for about 120 days before they need to be replaced, but sickle cells usually die in 10 to 20 days. This causes a shortage of red blood cells (anemia).Without enough red blood cells, your body can't get enough oxygen, causing fatigue.
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Episodes of pain: Periodic episodes of pain called sickle cell crises are a major symptom of sickle cell anemia. Pain develops when sickle-shaped red blood cells block blood flow through tiny blood vessels to your chest, abdomen, and joints. Pain can also occur in varius bones. The level of pain varies in intensity and can last for a few hours to a few weeks. Some people have only a few pain crises a year while others have 10 to 15 pain crises a year. Some adolescents and adults with sickle cell anemia also have chronic pain, which can result from bone and joint damage, ulcers, and various other secondary causes.
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Swelling of hands and feet: This swelling is caused by sickle-shaped red blood cells blocking blood flow to the hands and feet causing swelling of these areas.
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Frequent infections: Sickle cells can damage your spleen, leaving you more vulnerable to infections. Doctors often give infants and children with sickle cell anemia vaccinations and antibiotics to prevent potentially life-threatening infections.
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Vision problems: Tiny blood vessels that supply your eyes can become clogged up with sickled cells. This can damage the retina and lead to vision problems.
Medications Used To Treat Sickle Cell Disease
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Hydroxyurea (Droxia, Hydrea, Siklos). Daily hydroxyurea reduces the frequency of pain crises and might reduce the need for blood transfusions and hospitalizations. It can also increase your risk of infections.
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L-glutamine oral powder (Endari). The FDA recently approved this drug for treatment of sickle cell anemia. It helps to reduce the frequency of pain crises.
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Crizanlizumab (Adakveo). Given through a vein, it helps reduce the frequency of pain crises. Side effects can include nausea, joint pain, back pain and fever.
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Pain-relieving medications. Your doctor might prescribe narcotics to help relieve pain during sickle cell pain crises.
New Gene Therapy Treatments
What is Gene Therapy?
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Gene therapy aims to fix a faulty gene or replace it with a healthy gene to try to cure disease or make the body better able to fight disease.
How Does Casgevy Cure Sickle Cell Disease?
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Casgevy work by editing the patient’s blood stem cells in order to make them produce high levels of fetal hemoglobin, which is produced during fetal development and binds to oxygen more strongly than adult hemoglobin. The gene for fetal hemoglobin is deactivated after birth. Casgevy turns the fetal hemoglobin gene back on and fills the patients body with healthy hemoglobin cells. This dilutes the sickled hemoglobin in the body, effectively curing the patient of Sickle Cell Disease.
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Blood transfusions. In a red blood cell transfusion, red blood cells are removed from a supply of donated blood, then given through a vein to a person with sickle cell anemia. This increases the number of normal red blood cells, which helps reduce symptoms and complications.
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Stem cell transplant. Also known as bone marrow transplant, this procedure involves replacing bone marrow affected by sickle cell anemia with healthy bone marrow from a donor. The procedure usually uses a matched donor, such as a sibling, who doesn't have sickle cell anemia.