Patino et al. (2011) studied an epilepsy-related mutation that only affects the β1b subunit. Although their co-immunoprecipitation studies did not detect an association between β1b and NaV1.1 or NaV1.3 channels, they showed that β1b modulates the NaV1.3 sodium current in heterologous systems. Our study shows that the β1bWT subunit modulates voltage dependence of inactivation by shifting the curve to more negative potentials. Here, SCN1A is linked to epilepsy.