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 This evidence concerns the gene GPI and anemia (phenotype).