PERIPHERAL BLOOD SCN1A MRNA EXPRESSION AND ITS ASSOCIATION WITH DEMOGRAPHIC AND CLINICAL CHARACTERISTICS IN IRAQI CHILDREN WITH EPILEPSY: A CASE–CONTROL STUDY

Background: Epilepsy is a very common childhood neurological disorder with varying clinical presentations, partly due to genetic factors. Although the SCN1A gene codes for a subunit of the voltage-gated sodium channel, which is crucial in neuronal excitability, associations between SCN1A mRNA levels in the peripheral blood and childhood epilepsy have been poorly understood. Objective: The current study aimed to evaluate peripheral blood SCN1A mRNA expression in children with epilepsy in Iraq and its relationship to the demographic and clinical data of the studied children. Methods: Children with epilepsy (n = 70) and apparently healthy controls (n = 30) were selected by convenience sampling from the population of children aged 6 months to 6 years attending the Ibn Sina Teaching Hospital, Mosul, Iraq during November and December, 2025. The expression of SCN1A mRNA was determined in peripheral blood by reverse-transcription quantitative real-time PCR, GAPDH was used as a reference gene and relative expression was calculated by 2-ΔΔCt method. Data were not normally distributed and as such results were reported as medians and interquartile ranges, and groups compared using the Mann–Whitney U test. Results: Peripheral blood SCN1A mRNA expression was significantly higher in children with epilepsy than in controls (Mann–Whitney U test, P < 0.001). The median relative expression was 33.66 (interquartile range 23.84–46.50) in the epilepsy group and 1.08 (interquartile range 0.37–3.99) in the control group, and the fold change by the 2⁻ΔΔCt method was 35.02. The sex distribution did not differ significantly between the groups (P = 0.79). Among children with epilepsy, 56 (80%) had seizure onset at or before one year of age, and relative SCN1A expression was negatively correlated with age at seizure onset (Spearman’s ρ = −0.58, P < 0.001). Conclusion: Children with epilepsy in this study showed significantly higher peripheral blood SCN1A mRNA expression than healthy controls, and expression was inversely associated with age at seizure onset. These findings do not establish diagnostic accuracy or clinical utility; independent validation is required before peripheral SCN1A expression can be considered a candidate biomarker.