Congenital total external ophthalmoplegia associated with infantile spinal muscular atrophy. Fine structure of extraocular muscle.

A case of total congenital external ophthalmoplegia associated with infantile spinal muscular atrophy is presented. In the first 29 months of life, ophthalmoplegia has remained complete. Ultrastructure of lateral rectus extraocular muscle indicates a neurogenic process as the basis of the ophthalmoplegia. Light microscopy alone is insufficient to distinguish primary "myopathic" from "neurogenic" disease in external eye muscles.