Autosomal-Dominant Nocturnal Frontal Lobe Epilepsy has its onset typically during childhood, and is characterized by clusters of brief frontal lobe motor seizures during sleep.
These seizures are characterized by hyperkinetic movements (e.g., bicycling, ballism, or pelvic thrusting), tonic stiffening, or clonic jerking movements, often preceded by gasping, grunting, or vocaliztion.
They may occur several times per night and may be preceded by an aura, which may be that of impending fear, shivering, vertigo, or a feeling of falling or of being pushed. Patients often have the impression of breathing difficulties, and they may hyperventilate. The secondary generalization of these seizures is unusual. T
The electroencephalogram is characteristically normal interictally, and indicates bifrontal epileptiform discharges during a seizure.
Etiology
Mutations of three genes are known to cause this condition:
CHRNA4 (causing autosomal-dominant nocturnal frontal lobe epilepsy type 1, OMIM 600513), encoding for the neuronal nicotinic acetylcholine receptor alpha-4 subunit, on chromosome 20q.
CHRNB2 (causing autosomal-dominant nocturnal frontal lobe epilepsy type 3, OMIM-605375), encoding for the beta-2 subunit of the same receptor on chromosome 1.
CHRNA2 (causing autosomal-dominant nocturnal frontal lobe epilepsy type 4, OMIM 610353), encoding for the alpha-2 subunit of the same receptor located on chromosome 8p.
Autosomal-dominant nocturnal frontal lobe epilepsy type 2 was linked to chromosome 15q24, and the mutation is thought to affect the neighboring genes CHRNA3, CHRNA5, or CHRNB4.
References
Bernard G, Shevell MI. Channelopathies: a review. Pediatr Neurol. 2008 Feb;38(2):73-85. ReviPMID: 18206787