Loss of function variants (LOF) affecting CTNND2, located on the short arm of chromosome 5, have been linked to various neurodevelopmental disorders (NDD) and psychiatric conditions such as intellectual disability (ID) with or without dyslexia-like learning difficulties (Belcaro et al., 2015; Hofmeister et al., 2015), autism spectrum disorder (ASD) (Miller et al., 2020; Turner et al., 2015), attention deficit hyperactivity disorder (ADHD) (Adegbola et al., 2020), and schizophrenia (Chen et al., 2023). This evidence concerns the gene CTNND2 and attention deficit-hyperactivity disorder.