Mutation of Homeobox B8 (Hoxb8, only expresses in the microglia in mice) in mice causes pathological grooming, hyperanxiety, and social impairment deficits, which are similar to the obsessive-compulsive disorder (OCD) and autism spectrum disorders (ASDs) observed in human [58, 59]. This evidence concerns the gene HOXB8 and autism spectrum disorder.