A Mitochondrial encephalomyopathy is a form of encephalomyopathy that is associated with a mitochondrial disease. A Mitochondrial encephalomyopathy is a form of encephalomyopathy that is associated with a mitochondrial disease. Examples include MELAS and MERRF. These conditions can sometimes present together. KSS is sometimes included in this category, but it is not included in this category in MeSH.