FRG1 and muscular dystrophy: In this study, we demonstrate decreased proliferation rates of myoblasts expressing FRG1, an attribute that could contribute to the long term reduction in muscle regenerative potential and muscular dystrophy observed in transgenic mice overexpressing FRG1. We have verified expression and muscular dystrophy in the H-FRG1TG mouse and seen that thigh-derived myoblasts, but not diaphragm-derived myoblasts, from these animals demonstrate a proliferative defect by clonal analysis.