In humans, mutations in the NMD factor gene, UPF3B, cause intellectual disability (ID) and are strongly associated with autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD) and schizophrenia (SCZ).
Loss-of-function mutations in UPF3B result in variable clinical presentations including intellectual disability (ID, syndromic and non-syndromic), autism, childhood onset schizophrenia and attention deficit hyperactivity disorder.