Leigh Syndrome, French Canadian Type (LSFC)
Summary
LSFC is a mitochondrial disorder caused by deficiency of LRPPRC, a protein required for proper assembly of cytochrome c oxidase (complex IV of the mitochondrial respiratory chain). This impairs cellular energy production, particularly in the brain and liver.
Practical takeaway
This is primarily relevant if your partner is of French Canadian (Saguenay-Lac-Saint-Jean) descent. Carrier testing is available. Realised does not calculate reproductive risk or advise on reproductive decisions.
Evidence detail
What Carrier Status Means For You
You are not affected. One working copy of LRPPRC is sufficient. Standard 25/50/25 recessive inheritance applies.
Population Context
The A354V founder mutation is concentrated in the Saguenay-Lac-Saint-Jean region of Quebec, where carrier frequency reaches ~1 in 23. This remarkable frequency reflects the founder effect in this geographically isolated population. Outside French Canada, LRPPRC-related Leigh syndrome is extremely rare.
Limitations
23andMe tests 1 LRPPRC variant. Coverage is limited to the French Canadian founder mutation. Classic Leigh syndrome involves 75+ different genes — this entry covers only the LRPPRC-specific French Canadian form.