Abstracts

Rationale: Determine if blood mRNA expression patterns in children with newly diagnosed untreated epilepsy are different than those in healthy controls. Determine the differential expression patterns between epilepsy subjects with generalized onset or partial onset seizures compared to healthy controls. Methods: Blood was obtained from otherwise healthy pediatric subjects with newly diagnosed untreated epilepsy along with healthy pediatric controls. mRNA was isolated and hybridized to Affymetrix HGU 133 2.0+ microarrays. Analysis was performed using Genespring. Differentially expressed gene lists resulted from comparison of i) epilepsy and control groups and ii) seizure type subgroups with controls. Tissue expression and gene ontology analysis was performed using DAVID. Results: Thirty-seven epilepsy patients and 28 controls were included. Overall, 575 genes were differentially expressed in subjects with epilepsy compared to controls. The generalized seizure subgroup versus control (GvC) gene list and the partial seizure subgroup versus control (PvC) gene list were different (p < 0.05). Tissue expression analysis identified almost half of the genes in GvC and PvC as brain based. Functional group analysis identified several biologically relevant pathways. In GvC, these included mitochondria and lymphocyte activation. In PvC, apoptosis, inflammatory defense and cell motion pathways were identified. Conclusions: A unique, biologically meaningful mRNA expression pattern is detectable in the blood of pediatric subjects with new onset and untreated epilepsy. This analysis finds many similar pathways to those identified in brain studies examining lesional intractable epilepsy. Blood mRNA expression patterns show promise as a target for biomarker development in pediatric epilepsy.