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.