Among these genes, it is affirmative that TBR1 is a causative gene for intellectual disability; however, the pathogenic genes of other phenotypes remain unclear.
TBR1, a transcription factor involved in early cortical development, is a strong candidate for the intellectual disability phenotype seen in our patient and in patients with larger deletions in this region of the genome.
Because TBR1 is critical for glutamate receptor, ionotropic, <i>N</i>-methyl-D-aspartate receptor subunit 2B (<i>Grin2b</i>) expression and is a causative gene for autism and intellectual disability, we then generated CASK T740A (corresponding to rat CASK T724A) mutant mice using a gene-targeting approach.