For example, Puig-Vilanova et al. (Puig-Vilanova et al., 2014) found that in the diaphragm of COPD patients, compared to control subjects, muscle-specific microRNA expression was downregulated, while histone acetyltransferases (HATs) and deacetylases and myocyte enhancer factor 2C protein levels were higher; by contrast, DNA methylation levels, muscle fiber types and sizes did not differ between patients and controls. Here, MEF2C is linked to chronic obstructive pulmonary disease.