APOE and amyotrophic lateral sclerosis: Several other gene mutations have been identified in sporadic cases which may increase susceptibility to ALS, such as mutations in the KSP repeat region in the NEFH gene (encoding neurofilament heavy subunit) [94,95], apolipoprotein E ∑4 genotype (APOE) [96], decreased expression of EAAT2 protein [97,98] and alterations in the Vascular endothelial growth factor (VEGF) gene [99] to name a few (See Table 2).