[1] Univ Penn, Sch Vet Med, Dept Pathobiol, Philadelphia, PA 19104 USA
[2] Univ Penn, Sch Vet Med, Ctr Comparat Med Genet, Philadelphia, PA 19104 USA
[3] Childrens Hosp Philadelphia, Dept Neurol & Neurosci Res, Philadelphia, PA 19104 USA
[4] Univ Penn, Sch Med, Inst Human Gene Therapy, Philadelphia, PA 19104 USA
[5] Univ Penn, Sch Med, Dept Mol & Cellular Engn, Philadelphia, PA 19104 USA