NEFL and Dravet syndrome: Specifically, NfL levels were significantly increased in individuals with DS compared to controls at ages 40 and older (41–50 years, 15.9 vs. 8.3 pg/mL, p = 0.001; > 50 years, 31.0 vs. 11.7, p = 0.023) (Fig. 2f, Table 3).