What is it like?

Here's a parent's view: "At first the doctors just thought Avi had a seizure because he was growing so fast. He had more grand mal seizures, and they started him on medication. Each drug seemed to work for a while and then it was as if his body became immune to it. They tried more and more drugs, two or three at a time, and the seizures just became more frequent. The worst part was that Avi was slipping—he was changing. He was not as sharp and quick as he had been. We blamed it on the drugs, but it just got worse and worse. Over a 3-year period, after the seizures began, Avi's mind seemed to get slower and slower. Then came the little seizures that would cause his speech to sputter and hesitate and his mind to turn on and off, like someone was taking a light switch and flicking it up and down."

Progressive myoclonic epilepsies feature a combination of myoclonic and tonic-clonic seizures. Unsteadiness, muscle rigidity, and mental deterioration are often also present.

Who gets it?

This is a group of rare disorders. Hereditary metabolic disorders are often responsible, but sometimes metabolic test results are normal and the cause remains unknown.

The disorders affect both sexes. The age of onset can vary from infancy to adulthood, depending upon the specific type of myoclonic epilepsy.

Tell me more

Progressive myoclonic epilepsy is not a single disorder but includes a group of syndromes with various names. Some of them are:

• severe myoclonic epilepsy of infancy (Dravet syndrome)
• Unverricht-Lundborg disease (also called Baltic myoclonus)
• Lafora disease
• mitochondrial encephalopathies

Genetic testing is available to identify most of the disorders.

How is it treated?

The medical treatment of progressive myoclonic epilepsy is often successful only for a few months or years. These patients may require more than one seizure medicine. As the disorder progresses, the medications become less effective, and side effects may be more severe as more of them are used at higher doses. In such cases, it is often worthwhile to try lower doses.

Depakote (valproate)is most commonly used. Other seizure medicines used include Keppra (levetiracetam), Topamax (topiramate), Klonopin (clonazepam), and Zonegran (zonisamide). While Lamictal (lamotrigine)can be used, in rare patients the drug can make seizures worse. Neurontin (gabapentin), Tegretol/Carbatrol (carbamazepine), Trileptal(oxcarbazepine, and Dilantin (phenytoin) usually do not help and can worse the condition).

What's the outlook?

The outlook is generally unfavorable. Seizures are difficult to control and patients often lose abilities involving thinking and movement. However, the course of the various syndromes varies considerably from individual to individual.

Topic Editor: Gregory L. Holmes, M.D.
Last Reviewed: 10/21/06