The invention provides gene therapy vectors, such as adeno-associated virus (AAV) vectors, expressing a miniaturized human micro-dystrophin gene and method of using these vectors to express micro-dystrophin in skeletal muscle s including diaphragm and cardiac muscle and to protect muscle fibers from injury, increase muscle strength and reduce and/or prevent fibrosis in subjects suffering from muscular dystrophy.本發明提供表現小型化人微小肌縮蛋白基因之基因療法載體，諸如腺相關病毒（AAV）載體，以及在患有肌肉萎縮症之個體中使用此等載體在包含隔膜及心臟肌肉之骨胳肌肉中表現微小肌縮蛋白，並防止肌纖維損傷，增加肌肉力量以及減少及/或預防纖維化的方法。
