Which of the following is an intrinsic (inherited) cause of hemolytic anemia?

Which of the following is an intrinsic (inherited) cause of hemolytic anemia?

• A. Autoimmune hemolytic anemia
• B. DIC
• C. G6PD deficiency
• D. TTP

Answer: (C)

Intrinsic hemolytic anemia comes from abnormalities within red blood cells that are inherited. G6PD deficiency is a classic example because it is a genetic enzymopathy of the pentose phosphate pathway. G6PD makes NADPH, which is needed to keep glutathione in the reduced form. Without sufficient NADPH, red cells are vulnerable to oxidative damage from certain drugs, infections, or fava beans, triggering hemolysis. On a blood smear you may see Heinz bodies and bite cells as macrophages remove the damaged portions of hemoglobin. It’s usually inherited in an X-linked recessive pattern, so affected males are more common, though some females can be symptomatic carriers. In contrast, autoimmune hemolytic anemia is caused by antibodies targeting red blood cells—an acquired, extrinsic process. DIC and thrombotic microangiopathy cause red cell destruction through systemic processes or mechanical fragmentation, not an inherent defect of the red blood cells themselves.

Intrinsic hemolytic anemia comes from abnormalities within red blood cells that are inherited. G6PD deficiency is a classic example because it is a genetic enzymopathy of the pentose phosphate pathway. G6PD makes NADPH, which is needed to keep glutathione in the reduced form. Without sufficient NADPH, red cells are vulnerable to oxidative damage from certain drugs, infections, or fava beans, triggering hemolysis. On a blood smear you may see Heinz bodies and bite cells as macrophages remove the damaged portions of hemoglobin. It’s usually inherited in an X-linked recessive pattern, so affected males are more common, though some females can be symptomatic carriers.

In contrast, autoimmune hemolytic anemia is caused by antibodies targeting red blood cells—an acquired, extrinsic process. DIC and thrombotic microangiopathy cause red cell destruction through systemic processes or mechanical fragmentation, not an inherent defect of the red blood cells themselves.