Progressive myoclonic epilepsy type 1

Progressive myoclonic epilepsy type 1 (also called Unverricht-Lundborg disease or ULD) is a rare inherited form of epilepsy. Early development is normal in affected individuals. Signs and symptoms of the disorder typically begin between 6 and 15 years of age.

People with progressive myoclonic epilepsy type 1 experience episodes of involuntary muscle jerking or twitching (myoclonus) that increase in frequency and severity over time. Episodes of myoclonus may be brought on by physical exertion, stress, light, or other stimuli. Within 5 to 10 years, the myoclonic episodes may become severe enough to interfere with walking and other everyday activities.

Affected individuals also usually have seizures that involve loss of consciousness, muscle rigidity, and convulsions (tonic-clonic or grand mal seizures). Like the myoclonic episodes, these may increase in frequency over several years. However, the seizures may be controlled with treatment. After several years of progression, the frequency of seizures may stabilize or decrease.

Eventually, people with progressive myoclonic epilepsy type 1 may develop problems with balance and coordination (ataxia) and speaking (dysarthria). They may also experience depression. Another feature of this condition is involuntary rhythmic shaking. This shaking is called intentional tremor because it worsens during intentional movements.

People with progressive myoclonic epilepsy type 1 may live into adulthood. Life expectancy depends on the severity of the condition and a person's response to treatment. The severity of the condition can vary, even among members of the same family.