Early-childhood progressive myoclonus epilepsy presenting as partial seizures in dentatorubral-pallidoluysian atrophy.

PURPOSE

We explored the characteristics of epileptic seizures of progressive myoclonus epilepsy (PME) in 2 brothers with dentatorubral-pallidoluysian atrophy (DRPLA).

METHODS

We obtained the case history of the siblings and ictal and interictal EEGs. Postmortem examination or demonstration of elongated CAG repeat in the gene for DRPLA was used to confirm the diagnosis.

RESULTS

Two Japanese siblings developed PME characterized by versive or himiclonic seizures with or without secondarily generalized tonic-clonic convulsions. The elder brother regressed mentally and exhibited increasing spasticity after age 1 year. Myoclonus and seizures developed at age 4 years. The younger brother had shown psychomotor retardation before age 4 years, when he began to deteriorate further neurologically as the elder brother had. He also developed myoclonus and seizures at that age. Seizures in both patients remained partial until their deaths at ages 19 and 15 years, respectively. Ictal EEG verified partial onset of seizure evolving to generalized tonic-clonic seizure (GTCS). Interictal EEGs showed multifocal paroxysmal discharges with little or no diffuse paroxysms. Postmortem examination or genetic study confirmed the diagnosis of DRPLA.

CONCLUSIONS

Seizures of patients with DRPLA may present as partial seizures in children with early-onset PME.