mitochondrial encephalomyopathy, lactic acidosis and strokes

Last reviewed 02/2023

MELAS is maternally inherited neurodegenerative disorder. The clinical features become more severe with age.

The features of MELAS are:

  • myopathy
  • lactic acidosis
  • stroke-like episodes
  • occasionally, cardiomyopathy

Investigations should include a muscle biopsy to demonstrate fibres with abnormal mitochondria. The cerebrospinal fluid lactate level is elevated.

This neurological disease is caused by a maternally- inherited mutation at position 3243 in the mitochondrial genome. This point mutation disrupts one of the mitochondrial genes for tRNA-Leu and so disrupts synthesis of proteins essential for oxidative phosphorylation.