DUX4 and facioscapulohumeral muscular dystrophy: Using the full Yao et al. (2014) (30) 114 gene DUX4 target biomarker, we found 19.7% of FSHD single cells and 7.8% of control cells had some detectable level of DUX4 target gene expression, again emphasizing the importance of using the full validated biomarkers.