More recently, a retrospective, single institution, long-term (>10 years) study was done in 75 DMD patients with a complete lack of dystrophin (determined by western blot) and genotyping, showed that DMD can be divided into 4 sub-phenotypes with different cognitive and motor outcomes [16], showing the complexity and heterogeneity of DMD. Here, DMD is linked to Duchenne muscular dystrophy.