Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) 22q13.3 deletion syndrome ?
    ### Response:
    22q13.3 deletion syndrome, also known as Phelan-McDermid syndrome, is a chromosome abnormality caused by the loss (deletion) of a small piece of chromosome 22. The deletion occurs near the end of the long arm (or q arm) at a location designated as q13.3. The signs and symptoms of this condition vary widely from person to person.
    