Below is an instruction from Human. Write a response.
    ### Instruction:
    How many people are affected by 16p11.2 deletion syndrome ?
    ### Response:
    Most people tested for the 16p11.2 deletion have come to medical attention as a result of developmental delay or autistic behaviors. Other individuals with the 16p11.2 deletion have no associated health or behavioral problems, and so the deletion may never be detected.
    