Ace the NBEO Systemic Disease Challenge 2026 – Unlock Your Optometry Superpowers!

Sickle Cell Anemia is a genetic disorder primarily characterized by a defect in the hemoglobin molecule resulting from a specific mutation in the beta-globin gene. This condition leads to the production of abnormal hemoglobin known as hemoglobin S (HbS). A crucial aspect of this disorder is the increased destruction of red blood cells, resulting in their reduced lifespan, which typically is around 10-20 days, compared to the normal lifespan of 120 days.

Decreased bilirubin levels would not be consistent with Sickle Cell Anemia. Instead, patients with this condition often exhibit increased bilirubin levels due to the hemolysis (destruction) of red blood cells, resulting in the release of bilirubin into the bloodstream. This can lead to complications such as gallstones.

The other statements are accurate. The disease is indeed caused by a DNA substitution mutation where adenine is replaced with thymine, resulting in a change from glutamic acid to valine at the sixth position of the beta-globin chain. It predominantly affects individuals of African descent, as is evident from its higher prevalence among African Americans. Additionally, due to the chronic hemolysis associated with the disease, the bone marrow responds by increasing the production of new red blood cells,