Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to 22q11.2 duplication ?
    ### Response:
    People with 22q11.2 duplication have an extra copy of some genetic material at position q11.2 on chromosome 22. In most cases, this extra genetic material consists of a sequence of about 3 million DNA building blocks (base pairs), also written as 3 megabases (Mb).
    