RYR1 and facioscapulohumeral muscular dystrophy: These cell lines have contributed to the development of therapeutic approaches such as oligonucleotide-mediated exon skipping [5], read-through of non-sense mutations [6], and gene correction [7, 8] for DMD, to the study of ryanodine receptor 1 (RyR1) deficiency in congenital myopathies [14], cell senescence in myotonic dystrophy type I [15], the involvement of IL-6 and Akt in the pathogenesis of myasthenia gravis [16], the dysregulation of DUX4c [11] and the role of FAT1 [12] in FSHD, and the shutdown of quiescence pathways in ageing [17].