ALS2 and amyotrophic lateral sclerosis: A multitude of genes associated with ALS reveals shared contribution to endocytosis and vesicle transport such as alsin 2 (ALS2), vesicle membrane protein-associated protein B (VAPB), optineurin (OPTN), and valosin-containing protein (VCP), along with axonal transport and organelle traffickings such as spatacsin (SPG11) and OPTN [20, 22].