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Letters to the Editor
December 1983

Nonprogressive Congenital Neuromuscular Disease With Uniform Type 1 Fiber

Author Affiliations

Department of Neurology
Department of Pediatrics University Hospital 87031 Limoges, France

Arch Neurol. 1983;40(13):828-829. doi:10.1001/archneur.1983.04050120078017

To the Editor.  —We read with interest the article by Oh and Danon (Archives 1983;40:147-150). We also think that uniform type 1 fiber typing is an extreme form of type 1 predominance. Brooke1 considers that type 1 fiber predominance can be implicated when these fibers make up more than 60% of the fibers in the biopsy sample. Moreover, it seems that some of these cases are familial.We examined two brothers and a sister, all less than 11 years old, who had the following features in common: delayed motor developmental milestones, mild proximal muscle weakness, hyporeflexia, normal serum muscle enzyme levels, substantial reduction in mean duration of motor unit potentials, and nonprogression of the disease. Deltoid muscle biopsy specimens showed only a clear predominance of type 1 fibers (78%, 74%, and 67% ). The distribution of type 1 fibers was thus nonuniform, although no other morphologic abnormalities were detected under