Subcortical Band Heterotopia Presented With Refractory Epilepsy and Reversible Aphasia

Double Cortex Syndrome: An Unusual Cause of Seizures

Gray matter heterotopia (GMH) is caused by abnormal neuronal migration during brain development. Subcortical band heterotopia (SBH), or double cortex, is a rare variant of GMH that mainly affects female patients with epilepsy (PWE) with different degrees of mental retardation. We present the case of a 25-year-old woman who was admitted to the neurology department of our tertiary hospital with generalized tonic-clonic seizures. Her mother had a normal antenatal period and a history of labor. There was a history of immediate crying and normal appearance, pulse, grimace, activity, and respiration (APGAR) scores. She had delayed milestones, which affected various categories of child development. Physical examination revealed a global developmental delay. Laboratory values, including complete blood count, serum calcium, and arterial blood gas tests, were all within normal limits. An EEG showed significant abnormalities suggestive of epilepsy. An MRI of the brain showed a continuous band of gray matter located deep and parallel to the cortex in both cerebral hemispheres, suggesting double cortex syndrome (DCS).

DCX variants in two unrelated Chinese families with subcortical band heterotopia: Two case reports and review of literature

Introduction

Subcortical band heterotopia (SBH) is a rare brain developmental malformation caused by deficient neuronal migration during embryogenesis. Published literature on pediatric SBH cases caused by DCX mutations is limited.

Methods

The detailed clinical and genetic features of two pediatric SBH with DCX mutations were analyzed. The available literature on DCX mutations was reviewed.

Results

Both patients were girls with varying degrees of developmental delay. Patient 1 was short in stature with peculiar facial features. Patient 2 had an early seizure onset and developed drug-resistant epilepsy. Whole-exome sequencing (WES) revealed two de novo heterozygous variants of DCX (NM_178153.3), including a novel missense variant of c.568A > G (p.K190E) in P1 and a reported nonsense variant of c.814C > T (p.R272*) in P2. We reviewed all the available literature regarding DCX mutations. A total of 153 different mutations have been reported, with the majority of 99 (64.7 %) being missense mutations.

Conclusion

Our study expanded the mutational spectrum of DCX, which has important implications for the study of genotype-phenotype correlations. Furthermore, it provided insights to better understand SBH and genetic counseling.

[Neuroradiological and pathohistological markers of the main epileptogenic substrates in children.Cortical malformations]

High-resolution MRI is an important tool in the diagnosis of structural epilepsy in determining the seizure initiation zones, identification of the mechanisms of epileptogenesis in predicting outcomes and preventing postoperative complications in patients. In this article we demonstrate the neuroradiological and pathohistological characteristics of the main epileptogenic substrates in children using modern classification. The first part of the article is devoted to cortical malformations as the most common epileptogenic cerebral disorders.