Gene transfer to skeletal muscle, as demonstrated by an 8-year study in hemophilic dogs and a detailed analysis in hemophilia B mice (Cao et al., 2009; Niemeyer et al., 2009). The divergent outcomes between muscle and liver gene transfer do not appear to be related to differences in innate responses due to TLR3 signaling (Cao and Herzog, 2008). Despite this, skeletal muscle gene transfer remains a