Affiliations 

  • 1 Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
  • 2 Department of Biochemistry, Yokohama City University Graduate School of medicine, Yokohama, Japan
  • 3 Department of Pediatrics, Yamagata University Faculty of Medicine, Yamagata, Japan
  • 4 Department of Child Neurology, Nishi-Niigata Chuo National Hospital, Japan
  • 5 Segawa Memorial Neurological Clinic for Children, Tokyo, Japan
  • 6 Department of Pediatrics, Hospital Pulau Pinang, Pulau Pinang, Malaysia
  • 7 Genetic Department, Hospital Kuala Lumpur, Kuala Lumpur, Malaysia
  • 8 Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
Clin Genet, 2018 12;94(6):538-547.
PMID: 30280376 DOI: 10.1111/cge.13454

Abstract

N-methyl-d-aspartate (NMDA) receptors are glutamate-activated ion channels that are widely distributed in the central nervous system and essential for brain development and function. Dysfunction of NMDA receptors has been associated with various neurodevelopmental disorders. Recently, a de novo recurrent GRIN2D missense variant was found in two unrelated patients with developmental and epileptic encephalopathy. In this study, we identified by whole exome sequencing novel heterozygous GRIN2D missense variants in three unrelated patients with severe developmental delay and intractable epilepsy. All altered residues were highly conserved across vertebrates and among the four GluN2 subunits. Structural consideration indicated that all three variants are probably to impair GluN2D function, either by affecting intersubunit interaction or altering channel gating activity. We assessed the clinical features of our three cases and compared them to those of the two previously reported GRIN2D variant cases, and found that they all show similar clinical features. This study provides further evidence of GRIN2D variants being causal for epilepsy. Genetic diagnosis for GluN2-related disorders may be clinically useful when considering drug therapy targeting NMDA receptors.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.