In this study, we analyzed DUX4 and PAX7 signature expression in 39 FSHD and 24 control vastus lateralis (VL) or tibialis anterior (TA) muscle biopsies and studied their correlation with MRI-based biomarkers Turbo Inversion Recovery Magnitude (TIRM) hyperintensity and quantitative fat fraction. Here, DUX4 is linked to Facioscapulohumeral dystrophy.