Progressive Brain Atrophy in Alternating Hemiplegia of Childhood

Background Alternating hemiplegia of childhood (AHC) is a rare neurodevelopmental disorder that includes involuntary movements, paroxysmal symptoms, and various severities of nonparoxysmal symptoms. Objective To investigate the occurrence of structural brain abnormalities in patients with AHC during clinical courses. Methods Conventional brain magnetic resonance imaging findings and clinical courses were retrospectively investigated in 14 patients with AHC confirmed by ATP1A3 mutations. Results Progressive frontal dominant cerebral, diffuse cerebellar cortical, and severe hippocampal atrophy were observed in seven patients with irreversible severe motor and intellectual deterioration. All of these seven patients exhibited status epilepticus and required transient respiratory care. Isolated diffuse cerebellar cortical atrophy was observed in two adult patients with mild motor regression. Five patients without apparent deterioration displayed almost normal brain findings. Conclusions The areas of atrophy were consistent with the areas of increased expression of the Na+/K+‐ATPase α3 subunit encoded by ATP1A3. Some of paroxysmal and nonparoxysmal neurological symptoms are considered as related to the areas of brain atrophy.