DUX4L9 and facioscapulohumeral muscular dystrophy: Crucial evidence that DUX4 was the culprit in FSHD was generated by Michael Kyba’s group who directly compared the effects of each of the then 6 proposed FSHD candidate genes (FRG1, FRG2, TUBB4q, ANT1, DUX4 and DUX4c).