[Unexceptional symptoms as expression of MELAS]

An 11-year-old girl and a 25-year-old woman were both initially referred to a neurologist with 'common' neurological problems: The girl suffered from tics, and later epilepsy, and her serum lactate concentration was elevated. She had unilateral hyperintensity of the left cerebral cortex and later developed diabetes mellitus. The woman had muscle weakness, diabetes mellitus and ptosis. In both patients, the problems turned out to be an expression of MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes). The first patient died at 18 years of age during an epileptic seizure with severe metabolic disturbances. The second patient developed bilateral perceptive hearing loss, epilepsy and cardiomyopathy and she was repeatedly admitted to hospital with stroke-like episodes. She died at 46 years of age. Both patients had the MELAS A3243G point mutation. MELAS is a maternally inherited mitochondrial disorder. The age of onset and symptoms are highly variable, even within one family. To date there are no curative treatment options for the disease. Diagnosing MELAS is important though, for optimising the treatment of the individual symptoms and genetic counselling.