- A transgene carrying an A2G missense mutation in the SMN gene modulates phenotypic severity in mice with severe (type I) spinal muscular atrophy. Monani, U.R., Pastore, M.T., Gavrilina, T.O., Jablonka, S., Le, T.T., Andreassi, C., DiCocco, J.M., Lorson, C., Androphy, E.J., Sendtner, M., Podell, M., Burghes, A.H. J. Cell Biol. (2003)