(A) Reverse transcriptase (RT)-PCRs reactions are shown for three selected alternative splicing events investigated for the following transcripts: MBNL1, MBNL2, and NUMA1. Samples are grouped in the following categories; controls (lanes 1–4), FECD CTG18.1 expansion positive (lanes 5–8), and FECD CTG18.1 expansion negative (lanes 9–11).