NEFL and proximal spinal muscular atrophy: Baseline levels of NFL (4598 ± 981 vs 148 ± 39, P = 0.001), tau (939 ± 159 vs 404 ± 86, P = 0.02), and GFAP (236 ± 44 vs 108 ± 26, P = 0.02) were significantly higher in SMA children than controls.