Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) anencephaly ?
    ### Response:
    Anencephaly is a condition that prevents the normal development of the brain and the bones of the skull. This condition results when a structure called the neural tube fails to close during the first few weeks of embryonic development. The neural tube is a layer of cells that ultimately develops into the brain and spinal cord.
    