OSCE Diagnostic Skills Practice Exam

Sickle cell disease is linked to a specific genetic defect that leads to the production of an abnormal type of hemoglobin known as Hemoglobin S (HbS). In individuals with sickle cell disease, the substitution of valine for glutamic acid at the sixth position of the beta-globin chain causes the red blood cells to deform into a sickle shape under low-oxygen conditions. This alteration affects the cells' ability to navigate the blood vessels properly, leading to various complications, such as pain crises and increased risk of infection.

Understanding this abnormal hemoglobin's structure highlights how it differs from other forms like Hemoglobin A (the normal adult hemoglobin), Hemoglobin C (which is associated with a different hemoglobinopathy), and Hemoglobin B (less commonly referenced). The identification of Hemoglobin S is crucial for diagnosing sickle cell disease and guiding further management of the condition.