In this regard, studies have demonstrated increased levels of TGF-β1 in both the serum and cerebrospinal fluid (CSF) of ALS patients (Houi et al., 2002; Iłz̈ecka et al., 2002) and in an ALS mouse model (Zubiri et al., 2018). Here, TGFB1 is linked to amyotrophic lateral sclerosis.