Common microRNAs in Epilepsy and Migraine: Their Possibility as Candidates for Biomarkers and Therapeutic Targets during Comorbid Onset of Both Conditions.

Epilepsy and migraine are chronic neurological disorders with shared clinical as well as pathophysiological mechanisms. Epileptic patients are at a higher risk of developing migraine compared to normal individuals and vice versa. Several genetic and environmental risk factors have been reported to be associated with the development of both diseases. Previous studies have already established standard genetic markers involved in various pathways implicated in the pathogenesis of both these comorbid conditions. In addition to genetic markers, epigenetic markers have also been found to be involved in the pathogenesis of epilepsy and migraine. Among the epigenetic markers, miRNAs have been explored at length and have emerged as significant players in regulating the expression of their target genes. miRNAs like miR-22, miR-34a, miR-155, miR-211, and Let-7b play a significant role in neuronal differentiation and seem to be associated with epilepsy and migraine as comorbid conditions. However, the exact shared mechanisms underlying the role of these miRNAs in these comorbid conditions are still unclear. The current review has been compiled with an aim to explore common microRNAs targeting the genes involved in shared molecular pathways leading to epilepsy and migraine as comorbid conditions. The new class of ncRNAs, i.e., tRNA transfer fragments, are also discussed. In addition, their role as potential biomarkers and therapeutic targets has also been evaluated. However, limitations exist, and based on the current literature available, only a few microRNAs seem to be involved in the pathogenesis of both these disorders.