Validation studies typically identify a gene associated with FSHD and determine if it is a DUX4 target gene, as with PITX1 (Dixit et al, 2007), FRG1 (Ferri et al, 2015), FRG2 (Thijssen et al, 2014) and CRYM (Vanderplanck et al, 2011). This evidence concerns the gene DUX4 and facioscapulohumeral muscular dystrophy.