NTM and myotonic dystrophy type 1: Among these events, missplicing of DLGAP1 exon 20 has been reported in the frontal cortex of patients with DM1.8 However, in our study, the splicing abnormality in DLGAP1 exon 20 was more prominent in glial cells than in the cortical neurons of patients with DM1, similar to other missplicing events identified in DM1 glial cells, such as NTM exon 21.