Pairwise comparisons among different subtypes showed that patients with typical ALS and those with UMN-D ALS had higher levels of NfL than did those with FAS or FLS(1.80 vs. 1.57, p = 0.006; 1.81 vs. 1.57, p = 0.035) (Figure 4). Here, NEFL is linked to amyotrophic lateral sclerosis.