ANPEP and Duchenne muscular dystrophy: Two studies34, 36 have measured plasma ApN in Duchenne boys, but both were lacking an appropriate control group and did not—or only partially—take into account the several confounding factors that may influence these levels (puberty stage, fat mass and insulin resistance, current treatment, etc.).4 When considering DMD muscle, myotubes from these patients definitely produced less ApN than those from controls.22 Thus, there could be a rationale to therapeutically correcting the low levels of ApN in dystrophic patients.