NAIP and amyotrophic lateral sclerosis: On the other hand, our analysis identified a number of CNV genes, including known ALS-related genes (i.e., NIPA1, NAIP, VPS54 and GRIN3B), which do not appear to exert any apparent influence on expression levels, suggesting that the expression of these genes may be not gene-dose dependent and that they are likely to represent secondary ‘passenger’ events in ALS pathogenesis.