Alternating Hemiplegia of Childhood With a de Novo Mutation in ATP1A3 and Changes in SLC2A1 Responsive to a Ketogenic Diet

BackgroundAlternating hemiplegia of childhood (AHC) is a rare condition characterized by an early onset of hemiplegic episodes and other paroxysmal or permanent neurological dysfunctions. Recently, mutations in the ATP1A3 gene have been identified as the causal mechanism of AHC. Regarding the differential diagnosis of AHC, glucose transporter 1 deficiency syndrome may be considered because these two disorders share some paroxystic and nonparoxystic features.Patient and resultsWe report a typical case of AHC harboring a de novo mutation in the ATP1A3 gene, together with a duplication and insertion in the SLC2A1 gene who exhibited marked clinical improvement following ketogenic diet.ConclusionBecause the contribution of the SLC2A1 mutation to the clinical phenotype cannot be definitely demonstrated, the remarkable clinical response after ketogenic diet led us to the hypothesis that ketogenic diet might be effective in AHC as it provides an alternative energy source for the brain.