학술논문
Mutations in GRIN2A and GRIN2B encoding regulatory subunits of NMDA receptors cause variable neurodevelopmental phenotypes.
Document Type
Article
Author
Endele, Sabine; Rosenberger, Georg; Geider, Kirsten; Popp, Bernt; Tamer, Ceyhun; Stefanova, Irina; Milh, Mathieu; Kortüm, Fanny; Fritsch, Angela; Pientka, Friederike K.; Hellenbroich, Yorck; Kalscheuer, Vera M.; Kohlhase, Jürgen; Moog, Ute; Rappold, Gudrun; Rauch, Anita; Ropers, Hans-Hilger; von Spiczak, Sarah; Tönnies, Holger; Villeneuve, Nathalie
Source
Subject
*METHYL aspartate
*MAMMALOGICAL research
*GENETIC mutation
*PHENOTYPES
*INTELLECTUAL disabilities
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Language
ISSN
1061-4036
Abstract
N-methyl-D-aspartate (NMDA) receptors mediate excitatory neurotransmission in the mammalian brain. Two glycine-binding NR1 subunits and two glutamate-binding NR2 subunits each form highly Ca2+-permeable cation channels which are blocked by extracellular Mg2+ in a voltage-dependent manner. Either GRIN2B or GRIN2A, encoding the NMDA receptor subunits NR2B and NR2A, was found to be disrupted by chromosome translocation breakpoints in individuals with mental retardation and/or epilepsy. Sequencing of GRIN2B in 468 individuals with mental retardation revealed four de novo mutations: a frameshift, a missense and two splice-site mutations. In another cohort of 127 individuals with idiopathic epilepsy and/or mental retardation, we discovered a GRIN2A nonsense mutation in a three-generation family. In a girl with early-onset epileptic encephalopathy, we identified the de novo GRIN2A mutation c.1845C>A predicting the amino acid substitution p.N615K. Analysis of NR1-NR2AN615K (NR2A subunit with the p.N615K alteration) receptor currents revealed a loss of the Mg2+ block and a decrease in Ca2+ permeability. Our findings suggest that disturbances in the neuronal electrophysiological balance during development result in variable neurological phenotypes depending on which NR2 subunit of NMDA receptors is affected. [ABSTRACT FROM AUTHOR]