Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Bartter syndrome ?
    ### Response:
    What causes Bartter syndrome? Bartter syndrome may be caused by mutations in any one of several genes; the genetic cause in each case corresponds to the type of Bartter syndrome each affected individual has. Types I, II and IV typically result in the antenatal forms of Bartter syndrome (beginning before birth) while type III results in classical Bartter syndrome (usually beginning in early childhood).
    