The strongest association with epilepsy was rs3812718, or SCN1A IVS5N+5G>A: odds ratio (OR) = 0.85 for allele G (p = 0.0009) and 0.73 for genotype GG versus AA (p = 0.003).
A common SCN1A IVS5-91G>A (rs3812718) allele has been attributed to be a possible modifying factor for epilepsy susceptibility and therapeutic response.