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Leigh Syndrome, French-Canadian Type

What is Leigh Syndrome, French-Canadian Type?

Though multiple forms of Leigh syndrome exist with more than 30 causative genes identified, Leigh syndrome, French-Canadian type (LSFC) is exclusively caused by mutations in the LRPPRC gene. Individuals with LSFC often appear normal at birth, but begin to lose basic skills such as head control, sucking, walking, and talking in infancy or early childhood. They may also present with intellectual disabilities, dysmorphic features, irritability, vomiting, and seizures.

Intellectual and neurological symptoms associated with this condition are the result of lesions that develop in the midbrain and/or brainstem. The cells in these regions of the brain also begin to lose their protective coating (myelin sheath) which decreases the ability to process and respond to stimuli and initiate movement in voluntary muscles. In addition, LSFC often causes periods of metabolic crisis wherein symptoms may rapidly worsen, ultimately leading to significant breathing difficulties, heart problems, and vision loss.

How common is Leigh Syndrome, French-Canadian Type?

LSFC has never been reported outside of the French-Canadian population. Among those from the Saguenay-Lac Saint Jean of Quebec, the disorder is observed in approximately 1 in 2000 births.

How is Leigh Syndrome, French-Canadian Type treated?

Currently, there is no cure for LSFC and treatment is only supportive with the goal of alleviating symptoms as they arise. Medications may be provided for treatment of seizures, cardiac, metabolic, and respiratory issues, and muscle/movement disorders as they develop.

What is the prognosis for a person with Leigh Syndrome, French-Canadian Type?

Typically, symptoms of Leigh syndrome present during the first year of life and progress rapidly. The average life expectancy for children with LSFC is approximately five to six years. However, some individuals do not develop symptoms until adulthood and/or have a slowly progressing course of the disorder.


Association De L'acidose Lactique Du Saguenay-Lac-St-Jean

An organization formed to provide information and support to families living with Leigh syndrome, French-Canadian type. (Please note that the site is entirely in French.)

Genetics Home Reference

Explanations of an extensive number of genetic diseases written for the public by the U.S. government's National Institutes of Health.

National Organization for Rare Disorders (NORD)

Every day in America, 30 million people wake up to fight the battle with a rare disease. The vast majority are children. For most, there are no cures and few, if any, proven and effective treatments. NORD provides a unified voice for those courageous individuals, and the parents and other caregivers seeking to help them, so that they won’t have to fight that battle alone.

55 Kenosia Avenue
Danbury, CT 06810
Phone: 203-744-0100

The United Mitochondrial Disease Foundation

A non-profit offering support to all sufferers of mitochondrial disorders, UMDF also promotes research and education on these diseases.

8085 Saltsburg Rd., Suite 201
Pittsburgh, PA 15239
Phone: (412) 793-8077
Secondary Phone: (888) 317-UMDF

Other names for Leigh Syndrome, French-Canadian Type

  • Leigh syndrome due to mtDNA mutations
  • mtDNA-Associated Leigh syndrome and NARP
  • Cytochrome C oxidase deficiency
  • Respiratory complex chain deficiency type IV
  • Leigh syndrome, Saguenay-Lac Saint Jean type
  • LSFC
  • Cox deficiency, Saguenay-Lac Saint Jean type
  • Cox deficiency, French-Canadian type