Progress in Treating DMD

Credit: University of Pittsburgh Medical Center

Cross sections of muscle cells from a mouse treated with an adeno-associated virus vector carrying a mini-dystrophin gene (green area). Blue stains indicate cell nuclei.

Gene therapy for Duchenne muscular dystrophy (DMD) has been particularly challenging because of the enormity of the dystrophin gene. Fitting the 3 million base pair behemoth into a viral vector is not unlike Prince Charming trying to shove large feet into Cinderella's tiny glass slipper. Trimming the gene is one approach, but determining which parts to snip has taken time. Assistant professor of molecular genetics and biochemistry at the University of Pittsburgh Xiao Xiao, research associate Bing Wang, and senior research associate Juan Li whittled the gene down to three "mini genes" of less than 4,000 bases each--small enough to fit adeno- associated virus (AAV) and enter enough skeletal muscle cells to prevent degeneration in a mouse...