Fig. 1

DYNC1I1 exonic enhancers (eExons) regulate DLX5 and DLX6. a The DYNC1I1-DLX5/6 locus has two known eExons, DYNC1I1 exons 15 and 17 (colored in blue), that are functional limb enhancers and were shown to interact with DLX5 and DLX6 [4]. A 106 kb deletion (red line) that contains these eExons was found in an individual with split hand and foot malformation (SHFM) [10]. b A fictional example of a mutation in an eExon that could be overlooked in exome or genome sequencing studies. The chromatogram shows a synonymous mutation in an eExon that could leave the protein sequence unchanged but could affect a transcription factor binding site (logo plot below) leading to changes in the enhancer function of this eExon. DLX5 Distal-less homeobox 5, DLX6 Distal-less homeobox 6, DYNC1I1 Dynein cytoplasmic 1 intermediate chain 1