Several mutations in Nav1.1 DIVS4 have been identified [11,45,46], including R1636Q (R1) [47,48], found in Lennox-Gastaut syndrome or Dravet syndrome (DS), R1639G (R2) [49], found in DS, R1642S (R3) [11], found in DS, R1642M (R3) [50], found in DS, and R1645Q (R4) [48], found in DS (Table 1). The gene discussed is SCN1A; the disease is Dravet syndrome.