CRISPR/Cas9 technology generated a C to G change in the 5'-UTR of the gene. This mutation is homologous to a single-nucleotide polymorphism identified in Chinese Han children with severe intellectual disability. Transcripts of isoforms 2 and 4 are not changed but protein levels of isoforms 2 and 4 in both cerebral cortex and hippocampus are decreased. (J:307501)