Sickle Cell Disease

Sickle Cell is a disorder that affects the red blood cells, which use a protein called hemoglobin to transport oxygen from the lungs to the rest of the body. Hemoglobin molecules don’t form properly causing red blood cells to be rigid and have a concave shape. These irregularly shaped cells get stuck in the blood vessels and are unable to transport oxygen effectively causing pain and damage to the organs.

Sickle Cell Disease is inherited in an autosomal recessive pattern. A child will not inherit the disease unless both parents pass down a defective copy of the gene. People who inherit one good copy of the gene and one mutated copy are carriers. Carriers are clinically normal but can still pass the gene to their children.

Sickle Cell disease prevents oxygen from reaching the kidneys, lungs, heart, or other organs, causing a lot of damage. When sickle-shaped red blood cells get stuck in blood vessels this can cause episodes of pain called crises. Other symptoms include: delayed growth, strokes, and jaundice (yellowish hue to the skin and eyes because of liver damage).

Daily Life:

Newborns are screened for sickle cell disease with a simple blood test. If the disorder is not detected at birth, a blood sample can be used in a test called hemoglobin electrophoresis. This test will determine whether a person has Sickle Cell disease, or whether he or she is a carrier of the gene.

Babies and young children with Sickle Cell disease must take a daily dose of penicillin to prevent potentially deadly infections. Parents also take folic acid, which helps build new red blood cells. Doctors advise people with Sickle Cell to get plenty of rest, drink lots of water, and avoid too much physical activity. Blood transfusions that provide a patient with healthy red blood cells are a common treatment. People with more severe cases of the disease can be treated with a bone marrow transplant. This procedure provides the patient with healthy red blood cells from a donor. Currently the only cure for sickle cell disease is bone marrow transplantation. In this procedure a sick patient is transplanted with bone marrow from healthy, genetically compatible sibling donors. However only about 18 percent of children with sickle cell disease have a healthy, matched sibling donor. Bone marrow transplantation is a risky procedure with many complications.

Researchers are experimenting with attempts to cure sickle cell disease by correcting the defective gene and inserting it into the bone marrow of those with sickle cell to stimulate production of normal hemoglobin. Researchers used bioengineering to create mice with a human gene that produces the defective hemoglobin causing sickle cell disease. Bone marrow containing the defective hemoglobin gene was removed from the mice and genetically "corrected" by the addition of the anti-sickling human beta-hemoglobin gene. The corrected marrow was then transplanted into other mice with sickle cell disease. The genetically corrected mice began producing high levels of normal red blood cells and showed a dramatic reduction in sickled cells. Scientists are hopeful that the techniques can be applied to human gene transplantation using autologous transplantation, in which some of the patient's own bone marrow cells would be removed and genetically corrected.

Additional Facts:
In the United States, the disease most commonly affects African-Americans. About 1 out of every 500 African-American babies born in the United States has sickle cell anemia.

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