As previously mentioned, VEGF-A's role in ALS has been extensively studied, compared to VEGF-B, and the mechanism of motor neuron protection by VEGF-A primarily involves VEGFR-2 and Akt/PI3 K activation downstream of VEGFR-2 [54], or suppression of cell death pathways mediated by caspases [55]. This evidence concerns the gene KDR and amyotrophic lateral sclerosis.