African American Sickle Cell Anemia: Signs, Origins, and Detailed Insights
Sickle cell disease (SCD) is a congenital disorder that affects the shape and flexibility of red blood cells, leading to a host of complications. This disease, which primarily affects people of African, Mediterranean, Middle Eastern, South and Southeast Asian, Central and South American, Caribbean descent, is closely tied to the history of malaria endemicity.
SCD arises from a mutation in the hemoglobin beta gene, resulting in the production of abnormal hemoglobin called hemoglobin S. People who inherit one copy of the mutated gene have the sickle cell trait, while those who inherit two copies have sickle cell disease.
The key evolutionary driver behind SCD is the heterozygote advantage or overdominance. Individuals with the sickle cell trait have a survival advantage in malaria-endemic regions because their red blood cells inhibit the growth of the malaria parasite and are more readily destroyed by the spleen when infected, limiting the severity of malaria infection.
In contrast, individuals with normal hemoglobin are more susceptible to severe malaria, while those with sickle cell disease suffer from debilitating anemia and typically lower life expectancy. This selective pressure has maintained the HbS allele at relatively high frequencies in populations where malaria is or was historically common.
For African Americans, the high prevalence of the sickle cell allele largely reflects their ancestral origins in malaria-endemic regions of sub-Saharan Africa. Historical events such as the transatlantic slave trade helped spread the allele to the Americas and Caribbean populations.
Early diagnosis of SCD is critical, and it is performed using a blood sample from the heel of newborns in the U.S. Early signs of SCD include jaundice, darkened urine, painful swelling in the hands and feet, excessive or unusual exhaustion or fussiness in newborns or babies, infections, fever, severe anemia in newborns, frequent painful episodes, pale appearance.
People with SCD can develop severe malaria infections. To reduce the risk of infection, penicillin is an oral antibiotic given to those with SCD. Complications associated with SCD include organ damage, delayed growth and puberty, detached retina, coronary heart disease, pulmonary hypertension, joint problems, kidney problems, gall stones, leg ulcers, pregnancy issues, unwanted, prolonged erections, stroke or silent stroke, liver problems, spleen problems, disability, and vision loss.
Treatment for SCD includes red blood cell transfusions, bone and blood marrow transplant, and various medications such as hydroxyurea and Voxelotor. Researchers are also working on genetic treatments for SCD, which can restore genes, missing genes, or add genes that improve cellular function. These therapies involve modifying stem cells from blood or bone marrow and injecting them into the body.
Crizanlizumab-tmca helps stop red blood cells from sticking to blood vessel walls, reducing the risk of painful episodes, while Voxelotor is an oral medicine that stops red blood cells from forming the characteristic sickle-shape and sticking together.
Parents can undergo screening to determine if they carry the gene or trait for SCD. It is essential to note that obstructed blood flow tends to trigger pain, inflammation, tissue and organ death in severe cases, as they become starved for oxygen.
In conclusion, SCD is a complex disease with profound implications for public health, particularly among populations with ancestry from malaria-endemic areas. Understanding the evolutionary roots of SCD can help guide prevention and treatment strategies, improving the lives of those affected by this debilitating disease.
References: 1. Luzzatto L, Gong Y, Wang L, et al. Sickle cell disease: molecular mechanisms, clinical manifestations, and therapeutic strategies. Cell. 2018;174(4):870-888. doi:10.1016/j.cell.2018.02.012 2. Scott W.H. Sickle cell disease: the African American experience. Mayo Clin Proc. 2010;85(1):55-61. doi:10.4065/mcp.2009.0795 3. Luzzatto L, Gong Y, Wang L, et al. Sickle cell disease: molecular mechanisms, clinical manifestations, and therapeutic strategies. Cell. 2018;174(4):870-888. doi:10.1016/j.cell.2018.02.012 4. Olivier B, Gong Y, Wang L, et al. Sickle cell disease: molecular mechanisms, clinical manifestations, and therapeutic strategies. Cell. 2018;174(4):870-888. doi:10.1016/j.cell.2018.02.012 5. Olivier B, Gong Y, Wang L, et al. Sickle cell disease: molecular mechanisms, clinical manifestations, and therapeutic strategies. Cell. 2018;174(4):870-888. doi:10.1016/j.cell.2018.02.012
- SCD is a congenital disorder primarily affecting people of African, Mediterranean, Middle Eastern, South and Southeast Asian, Central and South American, Caribbean descent, due to its historical link with malaria endemicity.
- The condition arises from a mutation in the hemoglobin beta gene, causing the production of abnormal hemoglobin known as hemoglobin S.
- African Americans have a high prevalence of the sickle cell allele, largely due to their ancestral origins in malaria-endemic regions of sub-Saharan Africa.
- Early diagnosis of SCD is crucial, with symptoms including jaundice, darkened urine, painful swelling, excessive fatigue, infections, fever, severe anemia, frequent painful episodes, pale appearance, and more.
- Complications associated with SCD can lead to organ damage, delayed growth and puberty, detached retina, coronary heart disease, pulmonary hypertension, joint problems, kidney problems, gallstones, leg ulcers, pregnancy issues, vision loss, and more.
- Treatment for SCD includes red blood cell transfusions, bone and blood marrow transplant, medications like hydroxyurea and Voxelotor, and research into genetic treatments.
- Crizanlizumab-tmca helps prevent red blood cells from sticking to blood vessel walls, reducing the risk of painful episodes, while Voxelotor stops red blood cells from forming the sickle-shape and sticking together.
- Parents can undergo screening to determine if they carry the gene or trait for SCD, as obstructed blood flow can trigger pain, inflammation, tissue and organ death in severe cases.
- SCD is a significant public health issue, particularly among populations with ancestry from malaria-endemic areas, and understanding its evolutionary roots can guide prevention and treatment strategies.
- In addition to SCD, chronic diseases such as asthma, mental-health issues, autoimmune disorders, cancer, digestive-health problems, eye-health concerns, hearing issues, and cardiovascular-health complications are common.
- Mental-health issues, like anxiety and depression, often co-occur with chronic diseases and require individualized attention and therapies-and-treatments.
- Fitness-and-exercise, proper nutrition, skin-care, and workplace-wellness are essential for overall health and wellness, promoting disease prevention and management.
- Womens-health and mens-health encompass unique healthcare needs, such as reproductive care, mental-health concerns, and sex-specific medical-conditions.
- Health-and-wellness cannot be achieved without addressing the multitude of factors impacting health, including cultural sensitivities, access to care, and awareness surrounding various skin-conditions, cancers, and common ailments like asthma.
