Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) renal tubular dysgenesis ?
    ### Response:
    Renal tubular dysgenesis is a severe kidney disorder characterized by abnormal development of the kidneys before birth. In particular, kidney structures called proximal tubules are absent or underdeveloped. These structures help to reabsorb needed nutrients, water, and other materials into the blood and excrete everything else into the urine.
    