Epilepsy with myoclonic-atonic seizures

Alternate names

Myoclonic astatic epilepsy; Doose syndrome; Epilepsy with myoclonic-astatic seizures; Epilepsy with myoclono-astatic crisis

Definition

Epilepsy with myoclonic-atonic seizures is a rare epilepsy syndrome of early childhood. It is characterized by seizures of many different types, most often myoclonic-atonic, astatic, or generalized tonic-clonic seizures.

Cause

Changes in the SCN1A, SCN1B, GABRG2, CHD2, and SLC6A1 genes can cause or contribute to epilepsy with myoclonic-atonic seizures. However, in many cases the cause remains unknown.

Inheritance

Epilepsy with myoclonic-atonic seizures can be inherited from an affected parent or occur for the first time in a family as a sporadic disease.

Signs and symptoms

• It is characterized by seizures of many different types, most often myoclonic-atonic, astatic, or generalized tonic-clonic seizures.
• Seizures can be followed by drop attacks, which can lead to falls and injuries.
• Absence seizures may occur.
• People with the condition may experience several seizures each day.
• The epilepsy may result in a delay or regression of skills.
• Autistic features and ataxic (poorly controlled) movements have been reported in some cases.

Clinical presentation

For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed.

80%-99% of people have these symptoms

• Ataxia
• Atonic seizure
• EEG with spike-wave complexes (>3.5 Hz)
• Generalized myoclonic seizure
• Generalized myoclonic-atonic seizure

30%-79% of people have these symptoms

• Abnormal brain FDG positron emission tomography
• Developmental regression(Loss of developmental milestones)
• Dysarthria(Difficulty articulating speech)
• EEG with abnormally slow frequencies
• Epileptic encephalopathy
• Mental deterioration(Cognitive decline)
• Status epilepticus(Repeated seizures without recovery between them)

5%-29% of people have these symptoms

• Aggressive behavior(Aggression)
• Autistic behavior
• Febrile seizure (within the age range of 3 months to 6 years)(Fever induced seizures)
• Generalized non-motor (absence) seizure(Brief seizures with staring spells)
• Global developmental delay
• Impulsivity(Impulsive)
• Myoclonus
• Photosensitive tonic-clonic seizure
• Scoliosis
• Tremor

Diagnosis

• The EEG is usually abnormal.
• It shows epileptic discharges from both sides of the brain at the same time, and sometimes from all over the brain.
• The type of abnormal activity is called ‘spike and wave’ or ‘polyspike and wave’ activity.
• Children with this condition are not usually photosensitive.
• Brain scans and blood tests are usually normal.
• There is no genetic blood tests till now to find a mutation for this syndrome.

Treatment

• Treatment may include valproic acid alone or with other antiepileptic drugs.
• Ketogenic (high fat, low carb) diet has been successful in some.

Prognosis

Long term outlook ranges from persistent seizures that do not respond to treatment and intellectual disability, to complete seizure remission after several years and normal outcome.

NIH genetic and rare disease info

• NIH info on Epilepsy with myoclonic-atonic seizures

Epilepsy with myoclonic-atonic seizures is a rare disease.