Overview of the DiseaseThe term sickle cell disease (SCD) is the general term for a group of red blood cell disorders. Patients with SCD have abnormal hemoglobin, commonly called hemoglobin S or sickle hemoglobin, in their red blood cells. Hemoglobin is a protein in red blood cells that carry oxygen throughout the body. It is an inherited disease, meaning that it is not contagious such as with the common cold. SCD is a life-long illness, but there are effective treatments that can reduce symptoms and prolong life. In high income countries such as the United States, the life expectancy of an individual with SCD is 40-60 years.
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Genetics and Pathophysiology |
Mutations in the HBB gene cause sickle cell disease. In order for one to be affected by SCD, an individual must inherit two abnormal hemoglobin genes (one from each parent). When a person has two hemoglobin S genes, Hemoglobin SS, the disease is called sickle cell anemia. This is the most common and often most severe kind of SCD. Sickle hemoglobin is different than normal hemoglobin because it can form stiff rods within the red blood cell, turning it into a sickle shape. Sickle shaped cells are not flexible and can stick to vessel walls, causing a blockage. When this occurs, oxygen can't reach nearby tissues. The lack of tissue oxygen can cause severe pain and organ damage.
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Symptoms |
The severity of the disease varies from person to person. If a person has sickle cell disease, it is present at birth. In the United States, it is required for all newborn babies to be screened for SCD, so parents generally know about the disease before symptoms are present. Symptoms for SCD can be quite severe, and may include the following:
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References
http://www.nhlbi.nih.gov/health/health-topics/topics/sca/signs
http://www.nhlbi.nih.gov/health/health-topics/topics/sca
http://ghr.nlm.nih.gov/condition/sickle-cell-disease
https://www.blackaids.org/news-2012/1459-sickle-cell-disease-cuts-hiv-risk-in-us-blacks-400000-person-review
http://www.nhlbi.nih.gov/health/health-topics/topics/sca
http://ghr.nlm.nih.gov/condition/sickle-cell-disease
https://www.blackaids.org/news-2012/1459-sickle-cell-disease-cuts-hiv-risk-in-us-blacks-400000-person-review