Acquired mutations in PIGA gene gives rise to:

Paroxysmal nocturnal hemoglobinuria (PNH) is a hemolytic anemia that stems from acquired mutations in PIGA, a gene required for the synthesis of phosphatidylinositol glycan (PIG), which serves as a membrane anchor for many proteins. Because PIGA is X-linked, normal cells have only one active PIGA gene, a mutation of which is sufficient to cause PIGA deficiency. Robin’s Textbook of pathology 10th ed Page 450