Seizures represent an important medical feature of dup15q syndrome. Over half of all people with dup15q will have at least one seizure. Seizures most often begin between ages six months and nine years usually involving multiple seizure types including infantile spasms and myoclonic, tonic-clonic, absence, and/or focal seizures. Seizure onset can occur up through puberty and young adulthood in this population.  Affected individuals may start with one seizure type, with other types emerging as the individual ages. Children with epilepsy have been found to have lower cognitive and adaptive functions than those without epilepsy.

Infantile Spasms (IS): Dup15q syndrome is one of the most common known causes of infantile spasms. Infantile spasms are repetitive, but often subtle movements—such as jerking of the mid-section, dropping of the head, raising of the arms or wide-eyed blinks. Infantile spasms can be misdiagnosed as colic, reflux, or a startle reflex.  As many as 40% of individuals with seizures present initially with infantile spasms; of this group, approximately 90% subsequently develop other seizure types.

Lennox Gastaut Syndrome (LGS): Infantile spasms in individuals with dup15q syndrome often progress to Lennox Gastaut syndrome and other complex seizure patterns that may be difficult to control.  LGS is characterized by recurrent seizures (epilepsy) that begin early in life. Affected individuals have multiple types of seizures, a particular pattern of brain activity (called slow spike-and-wave) measured by a test called an electroencephalogram (EEG).

Developmental  Epileptic Encephalopathy (DEE): Some individuals with dup15q syndrome may also be considered to have a Developmental Epileptic Encephalopathy. Developmental and Epileptic Encephalopathy (DEE) refers to a group of severe epilepsies that are characterized both by seizures, which are often drug-resistant, as well as encephalopathy, which is a term used to describe significant developmental delay or even loss of developmental skills.


Suggested Evaluations

Physicians may order the following evaluations to help better diagnose and treat the individual.

Since seizures are so common in dup15q syndrome and can often go undetected, it is the recommendation that as soon as a family receives a diagnosis of dup15q syndrome they reach out to receive the care of a neurologist.

  • Establish care with a Neuro regardless of seizure presence
  • Baseline EEG, ideally an overnight 24-hour EEG
  • Annual 24-hour EEG as needed

Patients with dup15q syndrome feature a distinctive electroencephalography (EEG) signature or biomarker in the form of high amplitude spontaneous beta frequency (12–30 Hz) oscillations.

Patients with dup15q syndrome have shown abnormal sleep physiology with elevated beta power, reduced spindle density, and reduced or absent SWS compared to age-matched neurotypical controls.

Both of these EEG disturbances are in the absence of seizures.


Treatment Considerations

Response to treatment is variable. Some seizures are easily controlled with the first medication, other seizures are controlled for a while and then become more complex, and some affected individuals experience intractable seizures that have never been controlled with medication. Intractable epilepsy in individuals with dup15q may result in disabling secondary effects, including falls or developmental regression. This occurs in more than half of individuals with frequent, uncontrolled seizures or nonconvulsive status epilepticus. Some anti-seizure medications have side effects that may contribute to cognitive, behavioral, psychiatric, and sleep impairments

Children with dup15q syndrome who have epilepsy, particularly those with infantile spasms are likely to have a greater level of impairment in terms of cognitive and adaptive functioning relative to those without epilepsy. Identifying and controlling seizures early could be extremely beneficial for children with dup15q syndrome.

Identifying Infantile Spasms

PCP Infantile Spasm Advisory

Types of Seizures

Seizure/Epilepsy Treatment

Seizure Action Plan

Seizure First Aid Training

Seizure Support Resources