In summary, our results of mutation analyses of CUX family genes in patients with epilepsies including TLE and the functional and mouse model analyses suggest that CUX family gene deficiency is one of the bases for TLE and that increase of cell number in the entorhinal cortex projection neurons and resultant increase of glutamatergic synaptic transmission to hippocampus is a possible pathological mechanism for TLE. This evidence concerns the gene CUX1 and epilepsy.