Myopathies and Cerebral Dysfunction

Mitochondrial dysfunction accounts for an ever-increasing number of ophthalmologic and neurologic disorders that frequently affect the central nervous system and skeletal muscle (encephalomyopathies). Of relevance to neuro-ophthalmologists, these disorders often present with optic neuropathy, pigmentary retinopathy, macular pathology, ptosis, and chronic progressive external ophthalmoplegia, which can be clinical red-flags that may lead clinicians to suspect a mitochondrial disorder. Many mitochondrial disease patients present with classical mitochondrial disease syndromes such as Kearns-Sayre syndrome, Leber hereditary optic neuropathy (LHON), mitochondrial encephalomyopathy lactic acidosis, and stroke-like episodes (MELAS), myoclonic epilepsy with ragged-red fibers (MERRF), and mitochondrial neurogastrointestinal encephalomyopathy (MNGIE). Nevertheless, many patients do not manifest a classical syndrome, but rather present with other disorders that range from monosymptomatic to multisystemic disorders.