TABLE 1.
Inherited Epilepsy Syndromes Caused by Ion Channel Mutations
| Ion Channel (gene, locus) | Syndrome (OMIM Number)* |
|---|---|
| *Online Mendelian Inheritance in Man database (http://www.ncbi.nlm.nih.gov/Omim/) | |
| †Cytogenetic location defined by using http://genome.ucsc.edu | |
|
Voltage-Gated Ion Channels | |
| Voltage-gated potassium channel, α subunit (KCNQ2, 20q13.2) |
Benign familial neonatal convulsions type 1 (121200) |
| |
Benign familial neonatal convulsions with myokymia (606437) |
| Voltage-gated potassium channel, α subunit (KCNQ3, 8q24) |
Benign familial neonatal convulsions type 2 (121201) |
| Voltage-gated sodium channel, β1 subunit (SCN1B, 19q13.1) |
Generalized epilepsy with febrile seizures plus type 1 (604233) |
| Voltage-gated sodium channel, α subunit (SCN1A, 2q24) |
Generalized epilepsy with febrile seizures plus type 2 (604233) |
| |
Severe myoclonic epilepsy of infancy, Dravet syndrome (607208) |
| |
Intractable childhood epilepsy with frequent generalized tonic–clonic seizures |
| Voltage-gated sodium channel, α subunit (SCN2A, 2q24) |
Benign familial neonatal–infantile seizures (607745) |
| |
Febrile seizures associated with afebrile seizures (604233) |
| Voltage-gated chloride channel (CLCN2, 3q27.1)† |
Juvenile myoclonic epilepsy (606904) |
| |
Juvenile absence epilepsy (607631) |
| |
Childhood absence epilepsy type 3 (607682) |
| |
Epilepsy with grand mal seizures on awakening (607628) |
| Voltage-gated calcium channel β4 subunit (CACNB4, 2q22-2q23) |
Juvenile myoclonic epilepsy (606904) |
| Voltage-gated calcium channel α1A subunit (CACNA1A, 19p13) |
Generalized epilepsy with episodic ataxia |
|
Ligand-Gated Ion Channels | |
| Nicotinic acetylcholine receptor, α4 subunit (CHRNA4, 20q13.2-q13.3) |
Autosomal dominant nocturnal frontal lobe epilepsy type 1 (600513) |
| Nicotinic acetylcholine receptor, β2 subunit (CHRNB2, 1q21) |
Autosomal dominant nocturnal frontal lobe epilepsy type 3 (605375) |
| GABA-A receptor, α1 subunit (GABRA1, 5q34-q35) |
Autosomal dominant juvenile myoclonic epilepsy (606904) |
| GABA-A receptor, γ2 subunit (GABRG2, 5q31.1-q33.1) |
Generalized epilepsy with febrile seizures plus type 3 (604233) |
| Childhood absence epilepsy type 2 and febrile seizures (607681) | |