Persons with DS who were A+/T‐ had significantly elevated plasma GFAP compared to A‐/T‐ (64.343, 95% CI: 32.394, 96.181 pg/mL) and sibling controls (61.780, 95% CI: 23.434, 99.126 pg/mL, p = 0.001). Here, GFAP is linked to Dravet syndrome.