DUX4L9 and facioscapulohumeral muscular dystrophy: An increased DUX4c level was shown in all FSHD samples with the highest ones detected in the samples derived from patients with low D4Z4 copy numbers (5 or 6; Fig. 4B), except for the F7 sample corresponding to the affected trapezius muscle that presented important necrosis and fat accumulation (data not shown).