Focal Cortical Dysplasia (FCD) is a malformation of cortical development (Kabat and Król, 2012). It is increasingly known as one of the most common causes of pharmaco-resistant epilepsies in both adults and children (Kabat and Król, 2012) (Najm et al, 2014). Due to their resistance to pharmaco-intervention, FCD’s are one of the leading conditions requiring epilepsy surgery (Isaa, M.V et al, 2014).

Type II cortical dysplasia is the result of extensive alterations outside the temporal lobe. It is typically seen in children and exhibits more severe clinical symptoms (Kabat and Król, 2012). Recent developments have been made with regards to the cellular and molecular biology of FCD type II, however, the pathogenic mechanism remains mostly unidentified (Isaa, M.V et al, 2014).


The aim of this study was to “investigate whether abnormal gene regulation, mediated by microRNA, could be involved in FCD type II”.


Total RNA was used from brain tissue of patients with and without FCD type II. A variety of methods were implemented on genes involved in the mTOR pathway to validate their role. One of these techniques was quantitative polymerase chain reaction.

Current literature indicates that the mTOR pathway is involved in the pathogenesis of FCD type II. However, the exact biochemistry leading to this form of cortical malformation remains undetermined. The study therefore analysed the expression of microRNAs as a shortcut to gain a better understanding of the mechanisms involved in the pathogenesis of FCD type II.


NEUROG2, a transcription faction implicated in neuronal and glial fate specification, was found to be upregulated in FCD. A NEUROG2-target, called RND2, was also found to upregulated. In addition to this, strong nuclear expression of NEUROG2 was observed in balloon cells and dysmorphic neurons.


This presents a potential new molecular mechanism, in which NEUROG2 has an essential and dominant role in the pathogenesis of FCD type II.


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  1. Kabat, J., & Król, P. (2012). Focal cortical dysplasia – review. Polish Journal of Radiology77(2), 35–43.
  2. Najm, I.M., Tassi, L., Sarnat, H.B. et al. (2014). Epilepsies associated with focal cortical dysplasias (FCDs). Acta Neuropathol, 128: 5.
  3. Marin-Valencia, I., Guerrini, R., & Gleeson, J. G. (2014). Pathogenetic Mechanisms of Focal Cortical Dysplasia. Epilepsia, 55(7), 970–978.
  4. Avansini, S., Torres, F., Vieira, A. et al. (2018). Dysregulation of NEUROG2 plays a key role in focal cortical dysplasia. Annals of Neurology.