Journal of Genetic Medicine

Korean Society of Medical Genetics and Genomics (대한의학유전학회)
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Wide heterogeneity of congenital myasthenic syndromes: analysis of clinical experience in a tertiary center

  • Cho, Anna (Department of Pediatrics, Seoul National University Bundang Hospital) ;
  • Kim, Soo Yeon (Department of Pediatrics, Seoul National University Children's Hospital, Seoul National University College of Medicine) ;
  • Lee, Jin Sook (Department of Pediatrics, Gachon University Gil Medical Center, Gachon University College of Medicine) ;
  • Lim, Byung Chan (Department of Pediatrics, Seoul National University Children's Hospital, Seoul National University College of Medicine) ;
  • Kim, Hunmin (Department of Pediatrics, Seoul National University Bundang Hospital) ;
  • Hwang, Hee (Department of Pediatrics, Seoul National University Bundang Hospital) ;
  • Chae, Jong-Hee (Department of Pediatrics, Seoul National University Children's Hospital, Seoul National University College of Medicine)
  • Received : 2020.10.14
  • Accepted : 2020.10.28
  • Published : 2020.12.31
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Abstract

Purpose: Congenital myasthenic syndrome (CMS) is a clinically and genetically heterogeneous group of disorders characterized by impaired neuromuscular transmission. This study aims to provide the clue for early diagnosis and improved therapeutic strategies in CMS. Materials and Methods: Through the targeted panel sequencing including twenty CMS causative genes, eleven patients were genetically confirmed and enrolled in this study. A retrospective medical record review was carried out for the clinical and laboratory data analysis. Results: The age of patients ranged from 5 to 23 years, with the median age of 16 years. The peak age at onset of symptoms was the neonatal period. Seven out of the eleven patients were symptomatic at birth. The most commonly reported initial finding was generalized hypotonia with poor sucking and crying. Mean time to accurate diagnosis was 9.3±5.0 years. Total fifteen different variants in seven genes associated with CMS (DOK7, AGRN, RAPSN, CHRNE, COLQ, SLC5A7, and GFPT1) were identified. Conclusion: We describe the clinical and genetic characteristics of CMS patients and treatment outcome in a single tertiary center. High clinical suspicion and timely molecular diagnosis is particularly important for the tailored therapy to maximize clinical improvement in CMS.

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