NF1 and plexiform neurofibroma: However, there were no NF1 microdeletions in the DISC and REP1 cohorts [58], nor did we detect the 3-basepair in-frame deletion (NM_000267.3:c.2970_2972delAAT) of exon 22 (legacy exon 17), an NF1 genotype know to affect neurofibroma number [3], [58].