Citation for final published version:Thomas, Rhys 2017. Ultra-rare genetic variation in common epilepsies: a case-control sequencing study. Please note: Changes made as a result of publishing processes such as copy-editing, formatting and page numbers may not be reflected in this version. For the definitive version of this publication, please refer to the published source. You are advised to consult the publisher's version if you wish to cite this paper.This version is being made available in accordance with publisher policies. See http://orca.cf.ac.uk/policies.html for usage policies. Copyright and moral rights for publications made available in ORCA are retained by the copyright holders.

We report the presence of major cerebral migrational defects in five severely, multiply handicapped children with congenital cytomegalovirus (CMV) infection. These patients had both computed tomographic (CT) scan and magnetic resonance imaging (MRI) evidence of marked migrational central nervous system defects consistent anatomically with the spectrum of lissencephaly-pachygyria, a disorder commonly idiopathic or associated with chromosomal abnormalities or with unknown early gestational insults. Neuroradiologic features included broad, flat gyri, shallow sulci, incomplete opercularization, ventriculomegaly, periventricular calcifications, and white-matter hypodensity on CT scans or increased signal intensity on long-TR MRI scans. Evidence for congenital CMV infection included prenatal onset of microcephaly, periventricular calcifications, neonatal jaundice, hepatomegaly, elevated CMV-specific immunoglobulin M, or viral isolation from urine. Previous reports of the neurologic sequelae of CMV have emphasized varying degrees of psychomotor retardation, cerebral palsy and epilepsy due to polymicrogyria, periventricular calcification, microcephaly, or rarely, hydrocephalus. Our patients appear to represent extremely severe examples of the effects of CMV on neurologic growth, maturation, and development. Recognition of these severe migrational abnormalities was improved by use of MRI, a technique that affords superior definition of the nature and extent of gyral and white-matter abnormalities. We suggest that these abnormalities may be more common than has previously been recognized.

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