A de novo gene mutation that encodes a brain protein in a child with autism has been placed into the brains of mice. These mice then showed severe alterations of specific behaviors that closely resemble those seen in human autism spectrum disorder, or ASD.
source https://www.lifetechnology.com/blogs/life-technology-news-blog/brain-protein-mutation-from-child-with-autism-causes-autism-like-behavioral-change-in-mice