DMD and Duchenne muscular dystrophy: This challenge is further compounded by the very low and variable expression of induced dystrophin that has been observed in recent trials involving antisense oligonucleotides [13, 14, 17, 25, 26, 46] coupled with the observation that most DMD patient samples also have low level residual dystrophin expression at baseline, highlighting the necessity for a highly sensitive detection method capable of detecting dystrophin signal over a wide dynamic range to resolve even subtle differences between pre- and post-treatment biopsies [3].