MEF2A and facioscapulohumeral muscular dystrophy: At the myotube stage, the increase in the number of genes that were dysregulated in FSHD cells may be partly due to the FSHD-associated decreases in expression of the transcription regulatory MYF6 and MEF2A genes and abnormal increases in expression of MEIS2 after induction of differentiation to myotubes.