Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Allan-Herndon-Dudley syndrome ?
    ### Response:
    Allan-Herndon-Dudley syndrome is a rare disorder of brain development that causes moderate to severe intellectual disability and problems with movement. This condition, which occurs exclusively in males, disrupts development from before birth. Although affected males have impaired speech and a limited ability to communicate, they seem to enjoy interaction with other people.
    