Melas syndrome consists of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke. Three familial cases are described by members of the Departments of Neurology and Pediatrics, University of Texas Health Science Center, San Antonio, TX. In these 3 cases, the onset was in adulthood whereas the majority of previously described patients developed symptoms at 4 to 11 years of age. Early development is usually normal except for short stature. Other features include sensorineural hearing loss, headache, nausea and vomiting, seizures and basal ganglia calcifications by CT. The absence of ophthalmoplegia, heart block, retinal pigmentation, myoclonus, and cerebellar ataxia, seen in other mitochondrial myopathies, is noteworthy. The pathologic findings of MELAS are ragged red fibers, and lactic acidosis. Some have increased carnitine acetyl transferase activity in skeletal muscle.
The assessment of proposed treatments such as methylprednisolone and chlorpromazine is difficult because the course of MELAS is variable. The proband with the full syndrome in this report improved spontaneously and had remained stable for 16 months without therapy. 
COMMENT: MELAS is familial and inheritance is almost exclusively by maternal transmission. Egger J and Wilson J at the Hospital for Sick Children, Great Ormond Street, London, report a high ratio of affected to unaffected siblings with mitochondrial cytopathy, making Mendelian inheritance unlikely . Two other disorders associated with mitochondrial myopathy and cerebral disease are Kearns-Sayre syndrome and MERRF (myoclonus epilepsy and ragged red fibers). All 3 syndromes are characterized also by dementia, seizures, short stature, hearing loss and a positive family history. K-S syndrome includes ophthalmoplegia, retinal degeneration and cerebellar ataxia. MERRF includes myoclonus and ataxia. MELAS has cortical blindness and hemiparesis as distinctive features.