Causes & Effects of Sickle Cell Anemia

Sickle cell anemia is a disorder of the red blood cells that is passed down through the genes. Affected individuals may have the full-blown disorder, which significantly affects quality of life and can cause severe disability or even death. Others may be carriers who show no symptoms but are able to pass the disease to their children.

Biological Cause

Sickle cell anemia occurs when the gene to make hemoglobin is defective. This causes the body to produce an abnormal type of hemoglobin called hemoglobin S instead of the normal hemoglobin A, according to the Mayo Clinic. Hemoglobin S causes the red blood cells that carry it to become deformed into a sickle shape instead of the normal doughnut shape. This occurs because the hemoglobin S sticks together, creating fibers that stretch the red blood cell into the characteristic sickle shape.

Genetic Cause

Sickle cell anemia is an autosomal recessive trait, meaning that it must be inherited from both parents to affect the child. If you inherit only one sickle cell gene, you will have the sickle cell trait and be a carrier of the disease, but it will not directly affect your health. There is a 50 percent chance that someone who is a sickle cell carrier will pass along the gene. Therefore, two asymptomatic carriers have a 25 percent chance of having children with sickle cell anemia, the result if they both pass along the gene. Such a couple has a 50 percent chance of having a child who is a carrier, the result of one parent passing on the sickle cell gene and the other passing on the normal gene for hemoglobin. The gene is most often found in people of African, Spanish, Mediterranean, Middle Eastern and Indian descent, notes Nemours Children’s Health System.

Biological Effects

The major effect of the disease is severe anemia–the lack of sufficient red blood cells and therefore oxygen in the body. The malformed red blood cells of sickle cell anemia are more fragile than normal blood cells, which causes them to die within 10 to 20 days instead of living 120 or so days as normal red blood cells do, according to the National Heart, Lung and Blood Institute. This leads to a lower than normal level of red blood cells in the body. Red blood cells carry oxygen to the tissues, so the brain and other organs do not get enough oxygen when there are not enough red blood cells. Sickle cells also bind together to form clumps and strings, leading to blocked blood vessels.

Practical Effects

Individuals with sickle cell anemia exhibit many symptoms that affect their daily lives. Anemia caused by sickle cell disease leads to extreme fatigue and sometimes other symptoms such as shortness of breath, dizziness, headaches and cold hands and feet. Another effect of sickle cell anemia is the occurrence of pain crises, episodes of severe pain resulting when the sickle cells clump in the body. Other effects can include delayed growth, eye problems, swollen hands and feet, spleen damage, gallstones and an increased susceptibility to infections.

About this Author

Bridget Coila has been writing professionally since 1998 and specializes in health, science and nutrition topics. Some of her articles have appeared in “Oxygen,” “American Fitness” and “Suite 101.” Coila has a B.S. in cell and molecular biology from the University of Cincinnati and 10 years of medical research experience.