Further research has shown that the viral genome of AAV can be modified to transport modified DNA into target cells, making it a target for gene therapy research. In particular, it can transport DNA or RNA into cells that are missing a specific sequence. For example, in Duchenne muscular dystrophy, the mutations in the DMD gene cause a deficiency of the dystrophin protein. AAV can be used to transport an exogenous dystrophin into the cells of the body. This research is particularly useful for single-gene diseases that are missing a singular protein. Currently, AAV serotype 2 is also being studied for use in ovarian cancer treatments, hemophilia B, blindness, and spinal muscular atrophy.