About Sickle Cell Disease
Sickle cell disease is an inherited blood disorder that causes anemia, which means there aren’t enough healthy red blood cells to deliver sufficient oxygen throughout the body. Healthy red blood cells are round and glide easily through the circulatory system, delivering oxygen from the lungs to body tissue and taking carbon dioxide from body tissue to the lungs to be exhaled.
In sickle cell disease, the red blood cells are misshapen (curved like a sickle) and tend to be sticky and clump together. Normal red blood cells live for approximately 120 days, but sickle cells live only 10 to 20 days, leaving patients with a serious deficit of healthy cells to deliver oxygen throughout the body.
The primary symptoms of the disease are:
- anemia, resulting from insufficient oxygen in the body that causes fatigue and eventually organ damage
- chronic, sometimes severe, pain, resulting from the sticky, clumped sickle cells blocking blood flow in the smaller blood vessels
The disease is caused by a gene mutation inherited from both parents. Inheriting the gene from one parent causes someone to be a carrier of the disease, but not to have the disease. Therefore, a family history of the disease places a child at risk. Today, sickle cell disease mainly afflicts people whose families come from Africa, the Caribbean, Middle Eastern and Mediterranean countries, South and Central America, and India.
With very aggressive therapies, sickle cell disease can sometimes be cured. For all patients, treatment can prevent or help symptoms of the disease and associated pain. There are different types of the disease, determined by the specific genetic variant that is inherited. The most common, and most serious, form of the disease is sickle cell anemia. Hemoglobin SC disease and hemoglobin sickle beta thalassemia are two other common forms.
Diagnosing Sickle Cell Disease
Babies born in the United States are tested at birth for sickle cell disease. Hemoglobin is an iron-rich protein found in red blood cells, and gives blood its red color. A simple blood test is done to check for the presence of hemoglobin S, the type of hemoglobin found in sickle cell disease.
If hemoglobin S is present, further testing is done to determine whether there are one or two sickle cell genes involved. Two genes (one inherited from each parent) indicate that the baby has the disease; one gene (inherited from only one parent) indicates that the baby carries the trait, but does not have the disease. If sickle cell disease is present, additional testing for complications will be done, beginning with a test for anemia.