A more severe phenotype is observed in mice with global loss of function mutations in Ptchd1, including learning impairment, cognitive defects, hyperactivity, hyperaggression, and motor defects, mimicking symptoms of attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD), an umbrella term for a group of neurodevelopmental disabilities.12 Here, PTCHD1 is linked to autism spectrum disorder.