What is the primary cause of sickle cell disease?

Sickle cell disease is primarily caused by a genetic mutation that affects the structure of hemoglobin, the protein in red blood cells responsible for transporting oxygen throughout the body. This mutation leads to the production of an abnormal form of hemoglobin known as hemoglobin S (HbS). When oxygen levels are low, hemoglobin S causes red blood cells to deform into a sickle shape, which can obstruct blood flow and lead to various complications, such as pain crises and increased risk of infection.

Understanding the basis of sickle cell disease involves recognizing its inheritance pattern. It is an autosomal recessive disorder, meaning that a person must inherit two copies of the mutated gene (one from each parent) to express the disease. When only one copy is inherited, the individual is typically a carrier (sickle cell trait) but does not have the disease.

Other options such as infections, high altitudes, vitamin deficiencies, or exposure to toxins can influence the severity of sickle cell disease or cause related complications, but they are not the primary underlying cause of the condition itself.