Three regions within the 3.3-kb monomer were selected for bisulfite genomic sequencing (Figure 1): the 5' region (Sq-1); the middle region (Sq-2) around the DUX-4 transcriptional start site that was described for a single copy cloned from the 4q35 D4Z4 array of an FSHD patient [12]; and the 3' region (Sq-3), which was shown to be hypomethylated in glioblastomas [24]. Here, DUX4 is linked to glioblastoma.