Recent work that investigated survival with respect to miRNA biomarkers identified high serum levels of miR-206, miR-133a and miR-151a-5p to be associated with a slower rate of clinical decline in ALS.43 Another study showed that increased miR-181 expression (miR-181a-5p and miR-181b-5p) in cell-free plasma was associated with a greater risk of death and when combined with measurement of NfL as a dual miRNA–protein biomarker provided a prognostic indicator for the disease course in ALS.40 There are four main mature products of miR-181 (miR-181a, -181b, -181c and -181d). The gene discussed is NEFL; the disease is amyotrophic lateral sclerosis.