Brain atrophy in congenital neuromuscular disease with uniform type 1 fibers.

We report a patient with congenital neuromuscular disease with uniform type 1 fibers. The patient had manifested muscle weakness and running difficulty since early childhood. Ptosis and ophthalmoplegia were evident, in addition to facial and distal weakness. Her serum creatine kinase level was normal, and electromyography revealed low-amplitude and short duration of motor unit potentials. A muscle biopsy specimen demonstrated absolute predominance of type 1 fibers (> 98%) with no diagnostic structures. Her intelligence was borderline (IQ 80), and dilatation of the lateral ventricles was demonstrated by cranial CT. This is the first report of an abnormality in the central nervous system in congenital neuromuscular disease with uniform type 1 fibers.