Final answer:
Sickle cell disease or sickle cell anemia is caused by the production of hemoglobin S, leading to RBCs that cannot maintain their shape in low oxygen, causing severe health implications.
Step-by-step explanation:
The condition described, where the presence of an abnormal hemoglobin molecule prevents red blood cells (RBCs) from maintaining their shape when oxygen levels in the blood decrease, is known as sickle cell disease or sickle cell anemia. This is a genetic disorder that results from the production of an abnormal hemoglobin type, called hemoglobin S, which results in RBCs that are crescent or sickle-shaped, particularly at low oxygen concentrations. These misshapen cells are prone to getting lodged in narrow blood vessels, blocking blood flow and leading to serious health issues, including painful joints, delayed growth, blindness, and strokes, predominantly affecting individuals of African descent.