UPF2 and neurodevelopmental disorder: In line with this, a previous study identified significant enrichment of germline copy number variants of NMD genes in neurodevelopmental disorder patients [110], including UPF2, and also EJC genes including the chr 1q-located RMB8A. Interestingly, both copy-number gains and also losses of the same genes, for example, UPF2 and RMB8A, were linked to the phenotype, implying that NMD and EJC gene dosage disbalances impact NMD function and disease pathology.