VEGFA and amyotrophic lateral sclerosis: Several findings showed that the delivery of viral vectors encoding growth factors, such as IGF-1, glial-derived neurotrophic factor, vascular endothelial growth factor (VEGF) extends lifespan and slows the progression of the disease in ALS animal models (Acsadi et al., 2002; Kaspar et al., 2003; Azzouz et al., 2004; Dodge et al., 2010; Wang et al., 2016).