KIRREL3 and attention deficit-hyperactivity disorder: Although further characterisation of Kirrel3−/− mice for ADHD-like behaviours, such as inattention and impulsivity, will be required, Kirrel3−/− mice may be represented a mouse model of ASD comorbid with ADHD and could provide molecular and pathophysiological information, and insight into new treatments for ASD comorbid with ADHD.