Mis-splicing of FMR1 transcripts with an expanded CGG tract has recently been proposed as a potential mechanism underlying the absence of FMRP in FXS tissues despite the presence of gene transcripts.<h4>Methods</h4>We used human neural progenitors and neurons differentiated from FXS human pluripotent stem cells and RNA-seq to examine splicing patterns of expanded FMR1 transcripts. The gene discussed is FMR1; the disease is fragile X syndrome.