Hemoglobin (cont.)

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What is sickle cell disease?

Sickle cell disease is a genetic condition in which the quality of hemoglobin is defective. This condition can cause abnormal hemoglobin which, in turn, can result in abnormally shaped (sickled) red blood cells (see illustration). These abnormal red blood cells cannot easily pass through small blood vessels and, therefore, could deprive the body organs of adequate oxygen. Occasionally, sickle cells may block a blood vessel resulting in significant oxygen deprivation to the area depending on the blood supply.

Sickle cells also have a shorter life span than normal red blood cells (10 to 20 days compared to 120 days). This rapid turnover may result in inadequate time to replace the red blood cells and may result in anemia.

In order for a person to have sickle cell anemia, one defective hemoglobin gene must be inherited from each parent. If only one gene is inherited from one parent, then the condition is much milder and it is referred to as sickle cell trait.

Symptoms of sickle cell anemia vary depending on its severity. Patients with sickle cell trait may experience mild, if any, symptoms at all. In sickle cell disease, symptoms are more significant, especially in episodes of acute crisis. These symptoms can include:

Picture of Sickle Cell Red Blood Cell and Healthy Red Blood Cells
Picture of Sickle Cell Red Blood Cell and Healthy Red Blood Cells

What is thalassemia?

Thalassemia refers to a group of hereditary conditions with quantitative hemoglobin deficiency. The body's failure to make globulin molecules will lead to compensatory mechanism to make other less compatible globulin molecules. The different types of thalassemia are defined based on what type of globulin molecule is deficient. The severity of these conditions depends on the type of deficient globulin chain, the number of deficient globulins, and the severity of the underproduction. Mild disease may only present as mild anemia, whereas, severe deficiency may not be compatible with life.

Medically Reviewed by a Doctor on 4/11/2014

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