Figure 6.

Model of 4q-D4Z4–mediated regulation of atrophic genes transcription. (A) 4q-D4Z4 array is interacting with a subset of atrophic genes, organizing their chromatin structure and keeping on hold their transcription in healthy donor muscle cells. (B) In FSHD1 patients’ muscle cells, the deleted and hypomethylated 4q-D4Z4 array causes an impairment of D4Z4 interactome, leading to a chromatin switch toward an active state (mainly enhancer and promoter regions), which in turn results in the transcriptional up-regulation of the atrophic genes.