However, using adeno-associated viral (AAV) vectors, investigators have succeeded in transducing both skeletal and cardiac muscle with modified forms of dystrophin (mini-dystrophins) in animal models of DMD.61–62 A phase I gene therapy trial using AAV 2.5 delivery of a mini-dystrophin gene supports the safety and tolerability of intramuscular delivery; however, dystrophin expression was limited.63,64 Since this first gene therapy trial in DMD, advances have been made in vector design, muscle-specific promoters, and mini-dystrophin constructs. Here, DMD is linked to Duchenne muscular dystrophy.