In contrast, the R1620L mutation associated with intellectual disability and autism-but not epilepsy-reduced Na+ current density in neuroblastoma cells and expectedly decreased neuronal firing.
We first studied the biophysical and neurophysiological consequences of four mutations in the human Na+ channel gene SCN8A causing either mild (E1483K) or severe epilepsy (R1872W), or intellectual disability and autism without epilepsy (R1620L, A1622D).