Epilepsy and malformations of cortical development: new developments.

PURPOSE OF REVIEW Malformations of cortical development (MCD) are increasingly recognized as causes of epilepsy and neurodevelopmental disorders. This review summarizes recent developments in the classification, specifically focusing on how genetic and cellular pathway advances are changing our understanding of MCD and how this applies to clinical care. RECENT FINDINGS Recent studies have shown that mutations can have variable impact on not only the pattern of MCD but also the location of cortical involvement. Regulatory G protein GPR56 mutations can selectively cause polymicrogyria in the Sylvian fissure bilaterally. In addition, recent data suggest that somatic mutations can be detected in about 30% of patients with diffuse and focal MCD but the majority are not detectable with common sequencing. Similarly, MRI at higher field is able to detect abnormalities not seen on clinical scanners. The classification scheme and pathogenesis of MCD converge by common genes affecting similar pathways, which, in turn, modify the classification of these disorders. These advances are impacting treatment and genetic management. SUMMARY The classification of MCD in epilepsy has progressed from simple correlations with syndromes and imaging data to molecular pathways underscoring the significance of common mechanism in brain maldevelopment and epilepsy.

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