Indeed, even small in-frame deletions may have a severe pathophysiological consequence; for example, those affecting the amino-terminal actin-binding domain 1 (ABD1), encoded by exons 2–8, or the beta-dystroglycan binding region, encoded by exons 63–70, often result in a severe DMD phenotype [51, 53]. The gene discussed is DAG1; the disease is Duchenne muscular dystrophy.