Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to paroxysmal nocturnal hemoglobinuria ?
    ### Response:
    Mutations in the PIGA gene cause paroxysmal nocturnal hemoglobinuria.  The PIGA gene provides instructions for making a protein called phosphatidylinositol glycan class A. This protein takes part in a series of steps that produce a molecule called GPI anchor.
    