The identification of 50 DMD patients with in-frame deletions or duplications in the DMD gene of which 30 (60%) had mutations originating in the proximal hotspot region of the DMD gene was surprising, because a recent study reporting 24 in-frame DMD patients showed a preference for mutations in the distal hotspot region of the DMD gene [39]. Here, DMD is linked to Duchenne muscular dystrophy.