Hemispheric cortical dysplasia secondary to a mosaic somatic mutation in MTOR

Abstract

To define causative somatic mutations in resected brain tissue from an infant with intractable epilepsy secondary to hemispheric cortical dysplasia. Methods: Whole-exome sequencing was conducted on genomic DNA derived from both resected brain tissue and peripheral blood leukocytes. Comparison of the brain vs blood sequencing results was performed using bioinformatic methods designed to detect low-frequency genetic variation between tissue pairs. Results: Histopathology of the resected tissue showed dyslamination and dysmorphic neurons, but no balloon cells, consistent with focal cortical dysplasia type IIa. mTOR activation was observed by immunohistochemistry in the dysplasia. A missense mut..