Patients present with anemia, hemoglobin in urine, jaundice, and an increased risk of thrombosis. PNH occurs due to the mutation of a gene (PIGA) which encodes for the protein GPI, in hematopoietic progenitor cells. This leads to the activation of complement system which further causes nocturnal haemolysis.5 The gene discussed is PIGA; the disease is paroxysmal nocturnal hemoglobinuria.