Polymicrogyria‐associated epilepsy: A multicenter phenotypic study from the Epilepsy Phenome/Genome Project

<jats:title>Summary</jats:title><jats:sec><jats:title>Purpose</jats:title><jats:p>Polymicrogyria (<jats:styled-content style="fixed-case">PMG</jats:styled-content>) is an epileptogenic malformation of cortical development. We describe the clinical epilepsy and imaging features of a large cohort with <jats:styled-content style="fixed-case">PMG</jats:styled-content>‐related epilepsy.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>Participants were recruited through the Epilepsy Phenome/Genome Project, a multicenter collaborative effort to collect detailed phenotypic data on individuals with epilepsy. We reviewed phenotypic data from participants with epilepsy and <jats:styled-content style="fixed-case">PMG</jats:styled-content>.</jats:p></jats:sec><jats:sec><jats:title>Key Findings</jats:title><jats:p>We identified 87 participants, 43 female and 44 male, with <jats:styled-content style="fixed-case">PMG</jats:styled-content> and epilepsy. Median age of seizure onset was 3 years (range <1 month to 37 years). Most presented with focal epilepsy (87.4%), some in combination with seizures generalized from onset (23.0%). Focal seizures with dyscognitive features were most common (54.3%). Of those presenting with generalized seizure types, infantile spasms were most prevalent (45.2%). The most common topographic pattern was perisylvian <jats:styled-content style="fixed-case">PMG</jats:styled-content> (77.0%), of which the majority was bilateral (56.7%). Generalized <jats:styled-content style="fixed-case">PMG</jats:styled-content> presented with an earlier age of seizure onset (median age of 8 months) and an increased prevalence of developmental delay prior to seizure onset (57.1%). Of the unilateral, and asymmetric bilateral groups where <jats:styled-content style="fixed-case">PMG</jats:styled-content> was more involved in one hemisphere, the majority (71.4%) of participants had seizures that lateralized to the same hemisphere as the <jats:styled-content style="fixed-case">PMG</jats:styled-content> or the hemisphere with greater involvement.</jats:p></jats:sec><jats:sec><jats:title>Significance</jats:title><jats:p>Participants with <jats:styled-content style="fixed-case">PMG</jats:styled-content> had both focal and generalized onset of seizures. Our data confirm the involvement of known topographic patterns of <jats:styled-content style="fixed-case">PMG</jats:styled-content> and suggest that more extensive distributions of <jats:styled-content style="fixed-case">PMG</jats:styled-content> present with an earlier age of seizure onset and increased prevalence of developmental delay prior to seizure onset.</jats:p></jats:sec>