What is the Difference Between Normal Hemoglobin and Sickle Cell Hemoglobin?

The main difference between normal hemoglobin and sickle cell hemoglobin lies in their structure and function. Normal hemoglobin, also known as hemoglobin A (HbA), has a soft, round shape that allows red blood cells to pass easily through blood vessels and deliver oxygen effectively. On average, healthy red blood cells live for 120 days before being replaced by new ones.

In contrast, sickle cell hemoglobin, also known as hemoglobin S (HbS), is a defective type of hemoglobin that causes red blood cells to distort into a C-shape or the shape of a sickle. Unlike healthy red blood cells, sickle cells only live for 10–20 days. Sickle cell hemoglobin differs from normal hemoglobin by a single amino acid: valine replaces glutamate at position 6 on the surface of the beta chain. This structural difference can lead to a variety of symptoms and health complications, including blockage of small blood vessels and painful complications.

To summarize:

• Sickle cell hemoglobin causes red blood cells to become stiff, sticky, and sickle-shaped, which can block blood vessels and impede the movement of healthy oxygen-carrying blood.
• Normal hemoglobin has a smooth, disk-shaped, and flexible structure, allowing red blood cells to move through blood vessels easily.
• Sickle cell hemoglobin is defective due to a single amino acid difference compared to normal hemoglobin.
• Sickle cells only live for about 10 to 20 days, compared to normal red blood cells that can live up to 120 days.

Comparative Table: Normal Hemoglobin vs Sickle Cell Hemoglobin

The main difference between normal hemoglobin and sickle cell hemoglobin lies in the structure and function of the hemoglobin molecules. Normal hemoglobin, also known as Hemoglobin A (HbA), is found in healthy individuals and is responsible for transporting oxygen efficiently throughout the body. In contrast, sickle cell hemoglobin, also known as Hemoglobin S (HbS), is found in individuals with sickle cell anemia and is associated with abnormal, sickle-shaped red blood cells that can't transport oxygen effectively. Here is a comparison table highlighting the differences:

People with sickle cell trait carry one copy of HbA and one copy of HbS, while individuals with sickle cell anemia inherit two copies of the HbS gene.