Although many identified SNPs reside outside of exons, we were able to analyze fourteen SNPs located within exons in ten genes (ALAD, ANG, APEX1, APOE, HFE, OGG1, PON1, PON2, PVR and SOD2) and, with the exception of APOE, which is discussed further below, we were unable to find an association between any of these SNPs and ALS in our cohort [54]–[86] (Table 3). Here, SOD2 is linked to amyotrophic lateral sclerosis.