Seizure onset occurs within the first year of life in an otherwise normally developing infant. All seizure types can occur and are often resistant to antiepileptic drugs. The course of epilepsy tends to follow a pattern of febrile seizures at initial diagnosis, followed by a "catastrophic" phase of multiple seizure types that are poorly responsive to medication, followed by relative stabilization after about 5 years. Developmental delay becomes apparent within the second year of life and behavioral problems can be prominent. Other neurologic signs include hypotonia, ataxia, and myoclonus. A later-onset gait deterioration and a characteristic "crouch gait" stance have been described. Patients may have a family history of epilepsy or febrile seizures.
For more information, see OMIM.
G40.311 – Generalized idiopathic epilepsy and epileptic syndromes, intractable, with status epilepticus
G40.319 – Generalized idiopathic epilepsy and epileptic syndromes, intractable, without status epilepticus
230437002 – Severe myoclonic epilepsy in infancy
- Benign myoclonic epilepsy of infancy
- Epilepsy with myoclonic-astatic seizures – Doose syndrome
- Progressive myoclonic epilepsy syndromes – Unverricht-Lundborg disease, Lafora body disease, neuronal ceroid lipofuscinoses
- Lennox-Gastaut syndrome
- Ohtahara syndrome
- Infantile spasms – West syndrome
- Other genetic epilepsy syndromes – PCDH19, ARX, KCNQ2, KCNT1, CDKL5, etc