INTRODUCTION: Alternating Hemiplegia of Childhood (AHC) is a rare but severe syndrome caused by mutations in the ATP1A3 gene. Onset of symptoms is frequently in the neonatal period. Characteristic features include transient episodes of palsy affecting alternate sides of the body, oculomotor abnormalities, seizures, choreoathetosis and dysautonomia. We describe clinical features in an Ecuadorian girl with a de novo mutation in ATP1A3.

METHODS: Description of medical history and sanger sequencing of ATP1A3.

CASE DESCRIPTION: Refractory partial seizures began at the age of only two months. Alternating episodes of hemiplegia lasting minutes to 3-4 days become increasingly evident over the next months. She often suffered from asymmetric status dystonicus and partial status epilepticus partially responsive to epilepsy therapies (levetiracetam and benzodiacepines).  Motor milestones were severely delayed. She was able to walk with support at the age of three years. Initiation of an antioxidant cocktail therapy and flunarizine appeared to result in ~ 50% reduction in episodes. EEG´s showed focal slowing during partial seizure episodes. MRI, MRA, MR Spect, CT scan were unremarkable. She ultimately asphyxiated during a choking episode at four years old. A de novo mutation was identified in the ATP1A3 gene in exon 17; c.2401 G to A; D801N. CONCLUSIONS: The complex nature of symptoms in AHC makes early diagnosis a challenge. Additional research is needed to understand the role of ATP1A3 and the full phenotypic spectrum of this disorder.