FLT3LG and facioscapulohumeral muscular dystrophy: Overall, the mild FSHD-like model exhibited very low numbers of DUX4-FL-positive myonuclei, with the moderate model exhibiting a significant increase (> 5-fold) in DUX4-FL-positive myonuclei, and the severe model had the highest numbers of DUX4-FL-positive myonuclei, with a > 10-fold increase compared with the mild model (Figure S5).