DUX4 and facioscapulohumeral muscular dystrophy: We have previously shown that myoblasts expressing DUX4 overexpressed CXCL12 and secreted CXCL12 both in vivo and in vitro (Dmitriev, Kiseleva et al., 2016; p. 4 and Figure 2), which may attract MSCs that express the CXCR4 receptor to the FSHD muscles.