KTN1 variants have also been associated with several other neuropsychiatric or neurodegenerative diseases/phenotypes before, including attention-deficit/hyperactivity disorder (ADHD) (Xu et al., 2017; Luo et al., 2020b), substance use disorder (SUD) (Li et al., 2016; Stringer et al., 2016; Luo et al., 2020a), and cognitive dysfunction in the elderly (Han et al., 2017). Here, KTN1 is linked to attention deficit-hyperactivity disorder.