Autosomal dominant sleep-related hypermotor epilepsy

Sleep-related hypermotor epilepsy (SHE) is a form of epilepsy that is characterized by seizures that typically begin while a person is sleeping. The seizures often appear during childhood or adolescence and involve varying degrees of muscle (motor) activity, which can include large, complex, and repetitive movements (hyperkinetic seizures). Autosomal dominant sleep-related hypermotor epilepsy (ADSHE) is a form of SHE that runs in families. The specific features of ADSHE can vary, even among members of the same family.

People with ADSHE typically have seizures that start in a specific region of the brain (focal seizures). The seizures often occur in clusters during a phase of sleep called nonrapid eye movement (non-REM) sleep. They typically begin and end abruptly, with each seizure lasting no more than 2 minutes. Some seizures are characterized by minor motor activity that may simply wake a person from sleep, while others are more complex and include repetitive motor activity, such as flinging or throwing motions of the arms and bicycling movements of the legs. Seizures may also include muscle stiffness or abnormal body positions. Some affected individuals may get out of bed and wander around during a seizure, which can be mistaken for sleepwalking. Rapid breathing (hyperventilation); a sense of breathlessness; and vocalizations, such as moaning or crying, can also occur.

In some types of epilepsy, a pattern of unusual feelings or sensations (aura) occurs before the seizure. Upon waking from sleep, people with ADSHE may experience an aura that warns them of an oncoming seizure. Auras in people with ADSHE can be associated with a feeling of numbness, shivering, a sense of fear, dizziness (vertigo), and a feeling of falling or being pushed.

People with ADSHE typically develop seizures before the age of 20 years. The episodes tend to become milder and less frequent over time. Although many people with ADSHE have seizures that can be effectively managed with medication, approximately 30 percent of affected individuals have seizures that become resistant to medication.

Psychiatric disorders, behavioral problems, and intellectual disabilities have been reported in some individuals with ADSHE. It is unclear whether these additional features are directly related to the seizures or to the underlying genetic cause.