Oct 16, 2019 MELAS: Dietary supplement approved for rare mitochondrial disease

The naturally occurring amino acid helps ward off stroke-like episodes

The readily available nutrient taurine, when administered in high doses,
has been shown to relieve symptoms of a rare genetic disorder

© Imagepocket / Shutterstock

Japanese authorities have approved the first-ever therapeutic for MELAS syndrome, a rare genetic disorder that affects the nervous system and muscles.

MELAS, or ‘mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes’, typically begins in childhood with seizures, headaches, loss of appetite and recurrent vomiting. The symptoms gradually worsen to the point of stroke-like attacks, with temporary muscle weakness on one side of the body that can lead to altered consciousness, loss of motor skills, intellectual disability, and problems with vision and hearing.

Clinicians who specialise in treating MELAS have evaluated antioxidants, vitamin derivatives and numerous other therapies over the past 30 years with little success.

A nutrient called taurine is now the first to show definitive signs of efficacy.

In February 2019, Japan’s Pharmaceutical Safety and Environmental Health Bureau granted marketing authorisation to taurine for the prevention of stroke-like seizures in MELAS. Taurine, a naturally occurring amino acid abundant in fish and meat, is also approved in Japan for treating congestive heart failure.

The MELAS decision followed a year-long trial in which researchers across Japan administered high daily doses of the therapy to 10 patients with disease-causing mutations in their mitochondrial genomes. Before the study, all the patients had been experiencing multiple stroke-like episodes per year. During the study period, six participants had no episodes and the other four had only one each.

The investigators, led by neurologist, Yoshihide Sunada, from Kawasaki Medical School, also studied the molecular effects of taurine supplementation on blood cells from treated patients. Reporting in the May 2019 issue of Journal of Neurology, Neurosurgery and Psychiatry, they found that five of the 10 patients showed significant improvements in a taurine-related change linked to enhanced mitochondrial function.

Brain scans of MELAS patients with stroke-like episodes.

© 2018 Yoshihide Sunada

“Our study concludes that high-dose taurine supplementation can prevent stroke-like episodes in patients with MELAS,” Sunada says. He and his colleagues have continued monitoring the health of their patients for several more years and suggest that “the therapeutic effect persists for a long period, with no safety problems.”

To date, however, the researchers have only tracked the incidence of stroke-like episodes, and it is not known if taurine therapy helps with the other serious complications of MELAS such as heart failure and diabetes. Sunada’s team is planning a clinical trial to test for those effects.

Others who study the physiological effects of taurine expect to see a lessening of those other serious symptoms as well. Stephen Schaffer, a professor of pharmacology at the University of South Alabama, explains that “taurine should be an effective therapy against all the symptoms of MELAS, not just the symptoms of stroke-like episodes.”

The program-affiliated researchers contributing to this research are from the Kawasaki Medical School, Japan.


  1. Ohsawa, Y., Hagiwara, H., Nishimatsu, S., Hirakawa, A., Kamimura, N. et al. Taurine supplementation for prevention of stroke-like episodes in MELAS: a multicentre, open-label, 52-week phase III trial. Journal of Neurology, Neurosurgery and Psychiatry 90, 529–536 (2019). | Article
  2. Decision on marketing authorisation.| Article

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