SCN1A and migraine, familial hemiplegic, 3: Moreover, the gene SCN1A, encoding for the voltage gated sodium channel Nav1.1 alpha subunit, which is the target of hundreds of epileptogenic mutations (Marini and Mantegazza, 2010; Meisler et al., 2010; Catterall, 2012; Guerrini et al., 2014), has also been identified as the target of mutations responsible for FHM-3 (Dichgans et al., 2005).