DUX4 and facioscapulohumeral muscular dystrophy: Several DUX4-suppressing small molecules have been identified in 2D cell cultures, including pamapimod,67 an analogue of losmapimod, a small molecule that was recently tested in clinical trials as a potential treatment for FSHD,68,69 CK1 inhibitor (PF-670462)70 and rebastinib (DCC-2036).71 Initially, we tested these compounds in affected MPs of Patient 2 (F2.1), because this cell line had the highest DUX4 expression.