SCN1A Variants in Patients with Dravet Syndrome.

Cho,  Min Jung; Kwon,  Soon Sung; Lee,  Seung Tae; Kim,  Heung Dong; Chung,  Hee Jung; Lee,  Joon Soo; Lee,  Young Mock; Kim,  Se Hee; Kang,  Hoon Chul

doi:2017.25.1.9

Ann Child Neurol > Volume 25(1); 2017 > Article

Original Article

Journal of the Korean Child Neurology Society 2017;25(1):9-12.
DOI: https://doi.org/10.26815/jkcns.2017.25.1.9 Published online March 30, 2017.

SCN1A Variants in Patients with Dravet Syndrome.

Min Jung Cho, Soon Sung Kwon, Seung Tae Lee, Heung Dong Kim, Hee Jung Chung, Joon Soo Lee, Young Mock Lee, Se Hee Kim, Hoon Chul Kang

¹Divison of Pediatric Neurology, Department of Pediatrics, Severance Children's Hospital, Yonsei University College of Medicine, Epilepsy Research Institute, Seoul, Korea. hipo0207@yuhs.ac
²Department of Laboratory Medicine, Yonsei University College of Medicine, Seoul, Korea.
³Department Pediatrics of National Health Insurance Service Ilsan Hospital, Goyang, Korea.
⁴Department of Pediatrics, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.

Abstract

PURPOSE
The aim of this study is to examine the SCN1A variants in Korean patients with Dravet syndrome. METHODS: We conducted a retrospective study of clinically confirmed thirty-nine patients with Dravet syndrome who visit our hospital from January 2007 to May 2015. We analyzed the SCN1A variants by direct sequencing. We analyzed and classified SCN1A variants according to ACMG/AMP (American College of Medical Genetics and Genomics and the Association for Molecular Pathology) guideline. RESULTS: A total thirty-nine patients (female 22, male 17) were included. Among them, twenty patients (51.2%) with Dravet syndrome had pathogenic or likely pathogenic SCN1A mutations including fifteen truncating mutations (12 nonsense and 3 splice region mutations), 5 missense mutations. The remained variants in nineteen patients with Dravet syndrome classified into ten variants of unknown significances, and 9 benign variants. In our study, truncation mutations are located whole span of SCN1A protein, while half of missense mutations are located at higher density on pore loop (S5-S6) regions. CONCLUSION: Unlike previous known study, lower positive rate of SCN1A mutation of Dravet syndrome was revealed in our study. The importance of parental test (trio test) and other additional tests have been emphasized.

Key Words: Dravet syndrome, SCN1A mutation