Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE)
Incidence
No accurate data concerning the prevalence of Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) exist. It is likely that the disorder is under diagnosed or, in some cases, misdiagnosed. This condition has been reported in more than 100 families worldwide.
Clinical Characteristics
Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) is a rare seizure disorder characterized by clusters of nocturnal motor seizures, which are often stereotyped and brief (5 seconds to 5 minutes). They vary from simple arousals from sleep to dramatic, often bizarre, hyperkinetic events with tonic or dystonic features. The hyperkinetic manifestations may appear bizarre, sometimes with ambulation, bicycling movements, ballism (flinging or throwing arm movements), and pelvic thrusting movements. Affected individuals may experience aura which may consist of fear, a shiver, vertigo, or a feeling of falling or being pushed. Retained awareness during seizures is common. There may be vocalization, clonic features, urinary incontinence, and secondary generalization. Seizures may vary over time. A minority of individuals experience daytime seizures. Neurologic examination is normal and intellect is usually preserved. It is considered an epileptic syndrome. ADNFLE is lifelong but not progressive. As an individual reaches middle age, attacks may become milder and less frequent. The diagnosis of ADNFLE is made on clinical grounds along with an EEG, preferably a video EEG. Carbamazepine is associated with remission in about 70% of individuals, often in relatively low doses. Resistance to antiepileptic drugs (AEDs), present in about 30% of affected individuals, requires a trial of all appropriate AEDs.
Precipitants
They occur during sleep.
Provocation Tests
None reported.
Diagnostic Procedures
The diagnosis of ADNFLE is made on clinical grounds along with an EEG, preferably a video EEG. Clinically available molecular genetic testing reveals mutations in CHRNA4, CHRNB2, or CHRNA2 in approximately 10%-20% of individuals with a positive family history and fewer than 5% of individuals with a negative family history.