SCN1B and idiopathic generalized epilepsy: Another peculiarity that distinguishes SCN1B mutations linked either to CNS or to cardiac diseases is that, with the exception of the recently identified mutation G257R (Patiño et al., 2009) which is located in the β1B retained intronic region, all generalized epilepsy with febrile seizures plus (GEFS+) causing mutations are localized in the Ig-loop region (Figure 1), suggesting that the cell adhesion functions mediated by this region are clinically relevant (Brackenbury and Isom, 2011).