Long-term course of early onset developmental and epileptic encephalopathy associated with 2q24.3 microduplication

Takuya Masuda, Hitoshi Osaka, Naomi Tsuchida, Satoko Miyatake, Kou Nishimura, Toshiki Takenouchi, Takao Takahashi, Naomichi Matsumoto, Takanori Yamagata

Research output: Contribution to journalArticlepeer-review


Copy number variations (CNVs) have been related to developmental and epileptic encephalopathy (DEE). The 2q24.3 region includes a cluster of genes for voltage-gated sodium channels (SCN) and CNVs in this region cause DEE. However, the long-term course of DEE with a 2q24.3 duplication has not been described. A 20-year-old female developed epileptic encephalopathy in early infancy that was resistant to various antiseizure medications. Her seizures disappeared after starting vitamin B6 therapy. Therefore, her epilepsy was considered pyridoxine-dependent epilepsy. At 16 years old, whole exome sequencing revealed a 2q24.3 microduplication including SCN1A, SCN2A, SCN3A, SCN7A, and SCN9A. Quantitative PCR detected an increased copy number of 1.3 Mb on 2q24.3 involving these genes, but no gene mutation accounting for pyridoxine-dependent epilepsy. Considering that with this duplication she was reported to be seizure-free after infancy, she was able to be off antiseizure medications including vitamin B6. Our case involvingdrug-resistant epilepsy in early infancy had no recurrent seizures during long-term follow up. Detecting CNVs using whole exome sequencing data was useful to identify a 2q24.3 duplication unassociated with pyridoxine-dependent epilepsy, leading to cessation of unnecessary medications.

Original languageEnglish
Article number100547
JournalEpilepsy and Behavior Reports
Publication statusPublished - 2022 Jan


  • 2q24.3 microduplication
  • Copy number variations
  • Developmental and epileptic encephalopathy
  • Voltage-gated sodium channel

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology
  • Behavioral Neuroscience


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