Agenesis of the Corpus Callosum with Peripheral Neuropathy (Andermann Syndrome)
Summary
Andermann syndrome is a neurological condition combining two features: absence or underdevelopment of the corpus callosum (the major connection between the brain's two hemispheres) and progressive sensorimotor peripheral neuropathy. The SLC12A6 gene encodes a potassium-chloride cotransporter important for neuronal development and function.
Practical takeaway
Relevant primarily if your partner is of French Canadian descent. A carrier test can determine partner status. 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 SLC12A6 is sufficient. Standard 25/50/25 recessive inheritance applies.
Population Context
The T813fsX founder mutation gives the Charlevoix-Saguenay region of Quebec a carrier frequency of ~1 in 23 — remarkably high. Named after neurologist Frederick Andermann who described it. Outside French Canada, the condition is extremely rare.
Limitations
23andMe tests 1 SLC12A6 variant. Coverage is limited to the French Canadian founder mutation. Comprehensive sequencing is needed for non-French-Canadian individuals.