The Role of KRAS Mutations in Cortical Malformation and Epilepsy Surgery: A Novel Report of Nevus Sebaceous Syndrome and Review of the Literature

• Published in: Brain sciences Vol. 11; no. 6; p. 793
• Main Authors: Pepi, Chiara, de Palma, Luca, Trivisano, Marina, Pietrafusa, Nicola, Lepri, Francesca Romana, Diociaiuti, Andrea, Camassei, Francesca Diomedi, Carfi-Pavia, Giusy, De Benedictis, Alessandro, Rossi-Espagnet, Camilla, Vigevano, Federico, Marras, Carlo Efisio, Novelli, Antonio, Bluemcke, Ingmar, Specchio, Nicola
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 16.06.2021; MDPI
• Subjects: Age; Cognitive ability; Convulsions & seizures; Drug resistance; Dysplasia; EEG; Electroencephalography; Epilepsy; focal cortical dysplasia; Genetic diversity; hippocampal sclerosis; Hippocampus; Intellectual disabilities; KRAS genetic variants; Literature reviews; Magnetic resonance imaging; Missense mutation; Mutation; Nevus; nevus sebaceous syndrome; Patients; pediatric epilepsy surgery; RAS pathway; Review; Sclerosis; Seizures; Semiotics; Skin diseases; Skin lesions; Surgery; Temporal cortex
• ISSN: 2076-3425; 2076-3425
• DOI: 10.3390/brainsci11060793

The rare nevus sebaceous (NS) syndrome (NSS) includes cortical malformations and drug-resistant epilepsy. Somatic RAS-pathway genetic variants are pathogenetic in NS, but not yet described within the brain of patients with NSS. We report on a 5-year-old boy with mild psychomotor delay. A brown-yellow linear skin lesion suggestive of NS in the left temporo-occipital area was evident at birth. Epileptic spasms presented at aged six months. EEG showed continuous left temporo-occipital epileptiform abnormalities. Brain MRI revealed a similarly located diffuse cortical malformation with temporal pole volume reduction and a small hippocampus. We performed a left temporo-occipital resection with histopathological diagnosis of focal cortical dysplasia type Ia in the occipital region and hippocampal sclerosis type 1. Three years after surgery, he is seizure-and drug-free (Engel class Ia) and showed cognitive improvement. Genetic examination of brain and skin specimens revealed the c.35G > T (p.Gly12Val) KRAS somatic missense mutation. Literature review suggests epilepsy surgery in patients with NSS is highly efficacious, with 73% probability of seizure freedom. The few histological analyses reported evidenced disorganized cortex, occasionally with cytomegalic neurons. This is the first reported association of a KRAS genetic variant with cortical malformations associated with epilepsy, and suggests a possible genetic substrate for hippocampal sclerosis.