In C9-ALS iPSCs, a mean of 138 versus 13 identifiable intron 1 reads were derived from the Rd and the normal allele, respectively, while for the rest of the gene, a mean of 96 reads derived from the Rd allele compared with 51 from the normal allele (Fig 3B; n = 3). Here, C9 is linked to amyotrophic lateral sclerosis.