De Novo Mutations in the Gene Encoding STXBP1 (MUNC18-1) Cause Early Infantile Epileptic Encephalopathy

Nat Genet. 2008 Jun;40(6):782-8. doi: 10.1038/ng.150. Epub 2008 May 11.

Abstract

Early infantile epileptic encephalopathy with suppression-burst (EIEE), also known as Ohtahara syndrome, is one of the most severe and earliest forms of epilepsy. Using array-based comparative genomic hybridization, we found a de novo 2.0-Mb microdeletion at 9q33.3-q34.11 in a girl with EIEE. Mutation analysis of candidate genes mapped to the deletion revealed that four unrelated individuals with EIEE had heterozygous missense mutations in the gene encoding syntaxin binding protein 1 (STXBP1). STXBP1 (also known as MUNC18-1) is an evolutionally conserved neuronal Sec1/Munc-18 (SM) protein that is essential in synaptic vesicle release in several species. Circular dichroism melting experiments revealed that a mutant form of the protein was significantly thermolabile compared to wild type. Furthermore, binding of the mutant protein to syntaxin was impaired. These findings suggest that haploinsufficiency of STXBP1 causes EIEE.

Publication types

  • Case Reports
  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Amino Acid Sequence
  • Brain / diagnostic imaging
  • Chromosome Deletion
  • Chromosomes, Human, Pair 9 / genetics
  • Circular Dichroism
  • Electroencephalography
  • Epilepsies, Myoclonic / genetics*
  • Epilepsies, Myoclonic / pathology
  • Female
  • Genome, Human
  • Heterozygote
  • Humans
  • In Situ Hybridization, Fluorescence
  • Infant
  • Infant, Newborn
  • Magnetic Resonance Imaging
  • Male
  • Microarray Analysis
  • Molecular Sequence Data
  • Munc18 Proteins / chemistry
  • Munc18 Proteins / genetics*
  • Munc18 Proteins / metabolism
  • Mutation, Missense / genetics*
  • Neuroblastoma / genetics
  • Neuroblastoma / metabolism
  • Neuroblastoma / pathology
  • Nucleic Acid Hybridization
  • Protein Conformation
  • Qa-SNARE Proteins / metabolism
  • Radiography
  • Sequence Homology, Amino Acid
  • Tumor Cells, Cultured

Substances

  • Munc18 Proteins
  • Qa-SNARE Proteins
  • STXBP1 protein, human

Associated data

  • GEO/GSE10077