Third, in ALS patient-specific induced-pluripotent stem cells, including ALS patient-derived VCP(R155C and R191Q), SOD1(A4V), and FUS(R521G) mutations, increased intron retention is a dominant feature during early neural differentiation22,23, which is in contrast to the most frequent exon skipping type detected in our study. This evidence concerns the gene VCP and amyotrophic lateral sclerosis.