DMD and Duchenne muscular dystrophy: While the presence of mental retardation in one third of DMD patients is closely related to distal mutations affecting expression of C-terminal forms of dystrophin (e.g., [13]), no clear genotype–phenotype relationship was reported for the comorbid diagnosis of ASD, and patients with altered social behavior and communicative skills do not necessarily display mental retardation [6, 10, 11, 14].