Epileptic-dyskinetic
encephalopathies are rare
epilepsies characterized by early-onset epileptic
encephalopathies (EOEEs) with
involuntary movement. Herein, we investigated the impact of gene variants in epileptic-dyskinetic
encephalopathies. Four independent patients from four families who exhibited
involuntary movements were recruited from Tokyo Metropolitan Neurological Hospital. The inclusion criteria were as follows: onset within 1 year after birth, frequent
seizures, severe developmental delay and accompanying
involuntary movements. We detected four genetic mutations, including STXBP1, GNAO1, CYFIP2, and SCN8A variants. The
involuntary movements were drug-resistant. However, pallidal
electrocoagulation followed by
gabapentin were partially effective in treating
chorea and
ballismus of the extremities in patients with GNAO1 variants, and
perampanel partially suppressed
seizures and
involuntary movements in one patient with a SCN8A variant.
Movement disorders are common to many
neurodevelopmental disorders, including a variety of EOEEs. Although we could not establish a definitive correlation using genetic variants in patients with EOEE and
movement disorders,
involuntary movements in patients with EOEEs may be a key diagnostic finding. The usage of genetic variants could prove beneficial in the future as more patients are investigated with epileptic-dyskinetic
encephalopathies.