FUS and amyotrophic lateral sclerosis: Next, we examined the in vitro condensation of FUS, an RNA binding protein implicated in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) (Kwiatkowski et al, 2009; Vance et al, 2009), and one of the most-studied proteins in condensation research (Fig. 5C,D; Appendix Fig. S7A,B).