title: Rapsyn mutations in hereditary myasthenia: distinct early- and late-onset phenotypes.
abstract: Rapsyn mutations in 16 unrelated patients with a congenital/hereditary myasthenic syndrome were identified, and a mutation (N88K) common to each of them was found. Two distinct phenotypes were noted: early and late onset. The former is frequently associated with arthrogryposis multiplex congenita and life-threatening crises. The late-onset phenotype developed in adolescence or adulthood and was initially mistaken for seronegative myasthenia gravis. Recognition of this late-onset phenotype should prevent inappropriate immunotherapy.
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D019943:Amino Acid Substitution; D001176:Arthrogryposis / Q000235:genetics; D001208:Asia / Q000208:ethnology; D002648:Child; D002675:Child, Preschool; D003062:Codon / Q000235:genetics; D003241:Consanguinity; D004252:DNA Mutational Analysis; D005060:Europe / Q000208:ethnology; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D009124:Muscle Proteins / Q000235:genetics*; D020125:Mutation, Missense; D009157:Myasthenia Gravis / Q000145:classification / Q000453:epidemiology / Q000235:genetics*; D020294:Myasthenic Syndromes, Congenital / Q000453:epidemiology / Q000235:genetics; D010641:Phenotype; D017354:Point Mutation
chemical_list: D003062:Codon; D009124:Muscle Proteins; C051609:peripheral membrane protein 43K