Teaching NeuroImage: Human Polymerase Gamma Gene (POLG) Disorder Presenting as Refractory Status Epilepticus

A 31-year-old woman with severe childhood-onset dysmotility syndrome was admitted for encephalopathy and seizures. Video EEG demonstrated electrographic seizures of multifocal onset refractory to multiple antiseizure medications (figure 1, A and C). MRI of the brain revealed multiple hyperintensities (figure 1B) that progressed (figure 1D). Infectious, immunologic, and neoplastic workup was unremarkable. A comprehensive epilepsy panel demonstrated a human polymerase gamma gene (POLG) likely pathogenic variant, c.3401 (c.3401A>G), previously reported as recessive, and a novel variant of unknown significance, c.2725 (c.2725 G>A). We hypothesize both variants are predicted to act in a compound heterozygous fashion. POLG disorders present with a discrete phenotype in adults; diagnosis is critical as valproate can precipitate liver failure1,2 (figure 2).