SMCHD1 and Facioscapulohumeral dystrophy: In order to identify pathways involved in FSHD which are specific to the muscle, we took advantage of our collection of induced pluripotent stem cells13 and our procedure for production of innervated and contractile skeletal Muscle Fibres (MFs)14 to analyse gene expression in cells from FSHD1 or FSHD2 patients compared to healthy donors (Figure1A,B).