title: Clinical and histologic changes in the follow-up of a congenital myopathy.
abstract: A 19-year-old woman was born with congenital hypotonia, generalized weakness, and dysmorphic features. A muscle biopsy performed at age 18 months found that type I fibers were smaller and more numerous than type II fibers, and she was diagnosed with congenital fiber type disproportion. She grew up with moderate motor impairment, but after a stationary period her weakness progressed gradually and she developed a severe ophthalmoplegia. When she was 18 years old a second muscle biopsy still indicated the predominance of type I fibers but also the presence of central nuclei and strong oxidative enzyme activity in the center of most of the fibers; this was compatible with centronuclear myopathy. The diagnostic reconsideration raises questions about the pathogenesis of these diseases and the recognition of congenital fiber type disproportion as a distinct nosologic entity.
authors.affiliation: Department of Pediatric Neurology, Hospital Doce de Octubre, Madrid, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Camacho
authors.forename: Alberto
authors.initials: A
authors.lastname: Villarejo
authors.forename: Rogelio
authors.initials: R
authors.lastname: Simón
authors.forename: Fernando
authors.initials: F
authors.lastname: Mateos
authors.forename: Ana
authors.initials: A
authors.lastname: Cabello
mesh_terms: D000293:Adolescent; D000328:Adult; D001706:Biopsy; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D018656:Muscle Fibers, Fast-Twitch / Q000473:pathology; D018657:Muscle Fibers, Slow-Twitch / Q000473:pathology; D009123:Muscle Hypotonia / Q000151:congenital / Q000473:pathology*; D018482:Muscle, Skeletal / Q000473:pathology*