<p>This case report describes a unique case of hemiconvulsion-hemiplegia-epilepsy syndrome in a paediatric patient with an underlying hypomyelinating leukodystrophy. We present the clinical, neuroimaging and genetic findings of a 3-year-old girl with a myelin deposition disorder who presented with a prolonged febrile status epilepticus, followed by persistent left hemiplegia. Brain magnetic resonance imaging (MRI) revealed a pattern consistent with hemiconvulsion-hemiplegia-epilepsy syndrome, with unilateral cytotoxic oedema and increased cerebral blood flow in the right cerebral hemisphere cortex. The girl was treated with corticosteroid therapy and levetiracetam. Follow-up imaging showed cerebral atrophy ipsilateral to the seizure focus. Incomplete myelination pattern remained unchanged. No prior cases associating hypomyelinating leukodystrophy with hemiconvulsion-hemiplegia-epilepsy syndrome have been reported. This case expands the phenotypic spectrum of hypomyelinating disorders and raises the hypothesis that an underlying white matter vulnerability may predispose to or modify the course of hemiconvulsion-hemiplegia-epilepsy syndrome. Recognition of such associations may have implications for prognosis and management, including seizure control strategies and neurorehabilitation. Further reports are needed to determine the role of myelination in the development of epileptic syndromes.</p> Graphical Abstract <p></p>