FRG1 and facioscapulohumeral muscular dystrophy: Reduced levels of expression of RBFOX1 and misregulated splicing of RBFOX1-dependent muscle exons have been observed in patients affected by FSHD, as well as in a mouse model that overexpresses FRG1 (FSHD region gene 1), a candidate gene for this disease [127,128,129].