A patient with anemia is diagnosed with PNH (Paroxysmal Nocturnal Hemoglobinuria). What is the underlying defect that leads to this condition?

A Deficiency of glutathione peroxidase
B Mutation in the PIGA gene leading to a deficiency of GPI anchor proteins ✓
C Overproduction of hepcidin
D Defect in the ATP7A gene affecting copper transport

Explanation

PNH is characterized by the acquisition of a somatic mutation in the PIGA gene of hematopoietic stem cells, leading to a deficiency of glycosylphosphatidylinositol (GPI) anchor proteins. This deficiency makes red blood cells more susceptible to complement-mediated lysis.

Source

New England Journal of Medicine review on PNH
Hematology Hematology: Anemia Hematology: Anemia Hard MEDICAL Confidence: high