A myasthenic syndrome with congenital paucity of secondary synaptic clefts: CPSC Syndrome
Corresponding Author
Dr. L. M. E. Smit MD
Laboratory for Neuromuscular Diseases and the Department of Child Neurology, State University Utrecht, Utrecht, The Netherlands
Department of Child Neurology, University Hospital, Free University, Amsterdam, The Netherlands
Department of Neurology, Laboratory for Neuromuscular Diseases, State University, Ultrecht, P.O. Box 16250, 3500 CG Utrecht, The NetherlandsSearch for more papers by this authorDr. G. Hageman MD
Laboratory for Neuromuscular Diseases and the Department of Child Neurology, State University Utrecht, Utrecht, The Netherlands
Search for more papers by this authorDr. H. Veldman MD
Laboratory for Neuromuscular Diseases and the Department of Child Neurology, State University Utrecht, Utrecht, The Netherlands
Search for more papers by this authorP. C. Molenaar PhD
Department of Pharmacology, Sylvius Laboratories, Leiden University Medical Centre, Leiden, The Netherlands
Search for more papers by this authorB. S. Oen PhD
Department of Pharmacology, Sylvius Laboratories, Leiden University Medical Centre, Leiden, The Netherlands
Search for more papers by this authorDr. F. G. I. Jennekens MD
Laboratory for Neuromuscular Diseases and the Department of Child Neurology, State University Utrecht, Utrecht, The Netherlands
Search for more papers by this authorCorresponding Author
Dr. L. M. E. Smit MD
Laboratory for Neuromuscular Diseases and the Department of Child Neurology, State University Utrecht, Utrecht, The Netherlands
Department of Child Neurology, University Hospital, Free University, Amsterdam, The Netherlands
Department of Neurology, Laboratory for Neuromuscular Diseases, State University, Ultrecht, P.O. Box 16250, 3500 CG Utrecht, The NetherlandsSearch for more papers by this authorDr. G. Hageman MD
Laboratory for Neuromuscular Diseases and the Department of Child Neurology, State University Utrecht, Utrecht, The Netherlands
Search for more papers by this authorDr. H. Veldman MD
Laboratory for Neuromuscular Diseases and the Department of Child Neurology, State University Utrecht, Utrecht, The Netherlands
Search for more papers by this authorP. C. Molenaar PhD
Department of Pharmacology, Sylvius Laboratories, Leiden University Medical Centre, Leiden, The Netherlands
Search for more papers by this authorB. S. Oen PhD
Department of Pharmacology, Sylvius Laboratories, Leiden University Medical Centre, Leiden, The Netherlands
Search for more papers by this authorDr. F. G. I. Jennekens MD
Laboratory for Neuromuscular Diseases and the Department of Child Neurology, State University Utrecht, Utrecht, The Netherlands
Search for more papers by this authorAbstract
Two cases of a newly recognized myasthenic syndrome were investigated (CPSC syndrome). The course of the disease was observed for periods of 6 and 3 years. In infancy, exacerbations of the symptoms occurred during febrile illness, but thereafter the clinical course was stable and the children appeared to be only slightly handicapped. Biopsies were taken from the intercostal muscle in both patients. Microelectrode studies revealed small Mepp amplitudes. Light microscopy demonstrated predominance of type I fibers and focal type-grouping. There was a lowered cholinesterase activity and frequent branching of preterminal axons. Electron microscopy revealed that there were few, if any, folds of the postsynaptic membrane and that there were no signs of degeneration. Methods for localization of acetylcholine receptors (AChR) revealed a deficiency and altered distribution of AChRs at these postsynaptic membranes and the occurrence of extrajunctional AChRs in some muscle fibers. It is concluded that the syndrome is a clinicopathological entity, characterized morphologically by a congenital paucity of secondary synaptic clefts (CPSC syndrome).
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