Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to Weaver syndrome ?
    ### Response:
    Weaver syndrome is usually caused by mutations in the EZH2 gene. The EZH2 gene provides instructions for making a type of enzyme called a histone methyltransferase. Histone methyltransferases modify proteins called histones, which are structural proteins that attach (bind) to DNA and give chromosomes their shape.
    