Poly (ADP-ribose)-polymerase-1 (PARP1) is another secreted protein that is differentially expressed in XIST-silenced tissues and is activated in MS and different neurodegenerative diseases, including Huntington’s disease and amyotrophic lateral sclerosis (Figure 7, Tables S5 and S6) [85]. Here, PARP1 is linked to neurodegenerative disease.