Diplopia Due to Congenital Myasthenic Syndrome Mimics Divergence Insufficiency

Congenital myasthenic syndromes (CMS) are a genotypically and phenotypically heterogeneous group of neuromuscular disorders from the impaired neuromuscular transmission. Mutations in the AGRN gene manifest phenotypically as either early-onset or late-onset CMS. The late-onset type is characterized by ptosis, ophthalmoparesis, and mild facial and bulbar weakness. We reported a rare case of diplopia due to CMS mimicking divergence insufficiency.