Monkeys with a human gene turned on in their brains displayed behaviors similar to those seen in some people with autism, researchers reported Monday in Nature. The monkeys avoided social interactions, were overly anxious, and performed repetitive movements, namely obsessively running in circles.

Source: http://arstechnica.com/science/2016/01/first-monkeys-engineered-to-have-autism-like-symptoms-raise-hope-caution/