TGFB1 and amyotrophic lateral sclerosis: More recently, a study showed that R-loops, structures formed of three-stranded nucleic acid, are depleted in ALS patients carrying a mutation in the senataxin (SETX) gene, affecting gene expression including the expression of BAMBI, a negative regulator of TGF-β and ultimately, leading to TGF-β signaling pathway activation (Grunseich et al., 2018).