Immunohistochemical stains on most of the muscle samples from patients with XLMTM demonstrated a persistence of fetal-specific muscle isoforms or proteins such as desmin, vimentin, and fetal myosin heavy chain, in agreement with previous observations (Sarnat 1990; Soussi-Yanicostas et al. 1991; Sewry 1998; Romero and Bitoun 2011). Here, DES is linked to X-linked myotubular myopathy.