Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes with deterioration during pregnancy.

We report a 31-year-old woman who developed myopathy and neuropathy during pregnancy. She was diagnosed as having mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). A T-to-C transition mutation at nucleotide position 3271 was detected in the mitochondrial gene. Her symptoms subsided spontaneously and she delivered a male infant at 38 weeks of gestation. Prior reports on mitochondrial diseases with pregnancy are very rare, probably because of the early onset of the disease. The metabolic changes during pregnancy increase the stress on the mitochondrial function, particularly in patients with impaired mitochondrial function. Therefore pregnancy can aggravate mitochondrial diseases.