Table 1

Epilepsy syndromes caused by inherited mutations in ion channel genes

Channel	Gene	Channel	Epilepsy syndrome(s)
Sodium	SCN1A	α subunit of Na_V1.1	Severe myoclonic epilepsy of infancy (SMEI) Intractable epilepsy with generalised tonic-clonic seizures (IEGTC) Migrating partial seizures of infancy (MPSI) Generalised epilepsy with febrile seizures (GEFS+)
	SCN1B	β subunit of Na_V1.1	SMEI GEFS+
	SCN2A	α2 subunit of Na_V1.2	SMEI Ohtahara syndrome Benign familial neonatal infantile seizures (BFNIS) West syndrome Infantile spasms GEFS+
	SCN3A	α3 of Na_V1.3	Partial epilepsy
	SCN8A	α8 subunit of Na_V1.6	Infantile epileptic encephalopathy
Potassium	KCNQ2	K_V7.2	Benign familial neonatal convulsions Infantile encephalopathy Myokymia associated with neonatal or early infantile epilepsy
	KCNQ3	K_V7.3	Benign familial neonatal convulsions
	KCNMA1	Calcium-activated potassium BK (Big Potassium) channel	Generalised epilepsy with paroxysmal movement disorder
	KCNA1	K_V1.1	Epilepsy with episodic ataxia
	KCNA2	K_V1.2	Myoclonic epilepsy and ataxia
	KCNJII	Kir6.2	Developmental delay, epilepsy and neonatal diabetes mellitus (DEND syndrome)
	KCNT1	Sodium-activated potassium channel	MPSI
Calcium	CACNA1H	α subunit of t-type calcium channels	Childhood absence epilepsy
Calcium	CACNA1A	Ca_V2.1 channel α subunit	Episodic ataxia and childhood absence epilepsy
Acetylcholine receptor (AChR)	CHRNA4, CHRNB2 CHRNA2	Subunits of nicotinic AChr receptor	Autosomal dominant familial nocturnal frontal lobe epilepsy
GABA	GABRA1	α subunit of GABA receptor	Childhood absence epilepsy Idiopathic generalised epilepsy (IGE) Juvenile myoclonic epilepsy (JME) Infantile spasms, Lennox-Gastaut
	GABRB2	B2 subunit of the GABA receptor	Infantile spasms, Lennox-Gastaut
	GABRB3	β3 subunit of GABA receptor	Absence epilepsy Infantile spasms, Lennox-Gastaut
	GABRD	δ subunit of GABA receptor	GEFS+ JME
	GABRG2	γ2 subunit of GABA receptor	GEFS+ SMEI Childhood absence epilepsy IGE