Figure 2. Tissue specificity and number of reported epilepsy mutations in the 9 functional voltage-gated sodium channel genes.

A, conserved domains of the sodium channel α-subunit protein. D, homologous domains; p, pore loops; L, inter-domain loops; +, positively charged transmembrane segments contributing to voltage sensing. B, major sites of expression of the sodium channel genes and numbers of mutations identified in patients with epilepsy.