Peripheral blood gene expression signatures associated with epilepsy and its etiologic classification.

Heterogeneity in epilepsy often interferes with its diagnosis as well as treatment. To examine this heterogeneity at transcriptomic level, we performed whole-genome mRNA expression profiling in whole blood samples from 34 patients with epilepsy (PWE) (idiopathic, n = 13; cryptogenic, n = 9; and symptomatic, n = 12) and 41 healthy controls (HC) using Illumina HT-12 Expression Beadchip v4 microarray. In silico analysis using R software identified 165 genes to be significantly differentially expressed in PWE compared to HC (fold change>1.3, p < 0.05). Hierarchical clustering of resultant DEGs segregated idiopathic epilepsy from the rest of the epilepsy classes as well as HC. The class also displayed the most differential expression pattern with the highest number of DEGs among the three epilepsy classes. Gene ontology analysis revealed several biologically relevant inflammatory and other immune-related pathways. Our study provides insight into the relevance of altered blood gene expression patterns in understanding epilepsy and its etiologic classes.