Elevated IL-6 levels have also been proposed as a potential biomarker for severe course in ALS patients, akin to urinary p75NTR ECD, though this finding has so far only been demonstrated in carriers of the IL6R 358 Ala variant (Casault et al., 2019; Wosiski-Kuhn et al., 2021). Here, IL6R is linked to amyotrophic lateral sclerosis.