In this respect, we recently examined COPD patient limb skeletal muscle to address the potential involvement of denervation and found numerous indications of ongoing denervation-reinnervation (fibers of the same type grouped together), along with evidence for persistent denervation of muscle fibers (accumulation of small fibers with angular shape, expression of the denervation-inducible glycoprotein neural cell adhesion molecule). The gene discussed is CHL1; the disease is chronic obstructive pulmonary disease.