Guanine-rich repetitions can form G-quadruplexes or hairpins with internal loops, with GGGGCC hexanucleotide repeat expansions sequestering proteins from the cellular pool (for example, TDP-43 [65]) or leading to R-loops, which subsequently cause amyotrophic lateral sclerosis [57]. This evidence concerns the gene TARDBP and amyotrophic lateral sclerosis.