HTR5A and autism spectrum disorder: For example, patients with autism spectrum disorder (ASDs) have been known to show impaired social interactions (Wing and Gould, 1979), a disrupted 5HT system in the brain (Chugani et al., 1999; Makkonen et al., 2008; Nakamura et al., 2010), as well as under-connectivity between two cortical hemispheres (Just et al., 2004; Vidal et al., 2006; Courchesne et al., 2007; Damarla et al., 2010).