MYOD1 and muscular dystrophy: To establish a human in vitro model of LAP1B-associated muscular dystrophy, we immortalized primary fibroblast cells derived from two healthy individuals and patient-derived fibroblasts carrying a biallelic LAP1B-specific loss-of-function mutation (c.186delG) in TOR1AIP1 [17] (Figure 1a), and transduced them with a doxycycline-inducible MYOD1 for myoconversion [32].