chr16-9768993-G-T

Variant names:

• chr16-9768993-G-T
• rs751455326
• NM_001134407.3:c.2453C>A

Variant summary

Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PM1 PM2 PM5 PP3_Moderate PP5_Very_Strong

The NM_001134407.3(GRIN2A):​c.2453C>A​(p.Ala818Glu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A818T) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: GRIN2A NM_001134407.3 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 9.88
• Publications: 5 publications found

Genes affected

GRIN2A (HGNC:4585): (glutamate ionotropic receptor NMDA type subunit 2A) This gene encodes a member of the glutamate-gated ion channel protein family. The encoded protein is an N-methyl-D-aspartate (NMDA) receptor subunit. NMDA receptors are both ligand-gated and voltage-dependent, and are involved in long-term potentiation, an activity-dependent increase in the efficiency of synaptic transmission thought to underlie certain kinds of memory and learning. These receptors are permeable to calcium ions, and activation results in a calcium influx into post-synaptic cells, which results in the activation of several signaling cascades. Disruption of this gene is associated with focal epilepsy and speech disorder with or without cognitive disability. Alternative splicing results in multiple transcript variants. [provided by RefSeq, May 2014]

GRIN2A Gene-Disease associations (from GenCC):

• complex neurodevelopmental disorder

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• Landau-Kleffner syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
• continuous spikes and waves during sleep

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• early-onset epileptic encephalopathy and intellectual disability due to GRIN2A mutation

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• rolandic epilepsy-speech dyspraxia syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• self-limited epilepsy with centrotemporal spikes

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• neurodevelopmental disorder

  Inheritance: AR Classification: LIMITED Submitted by: G2P

ACMG classification

Our verdict: Pathogenic. The variant received 16 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 8 uncertain in NM_001134407.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr16-9768994-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 522855.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.851
• PP5: Variant 16-9768993-G-T is Pathogenic according to our data. Variant chr16-9768993-G-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 495226.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001134407.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GRIN2A	NM_001134407.3	MANE Select	c.2453C>A	p.Ala818Glu	missense	Exon 12 of 13	NP_001127879.1
	GRIN2A	NM_000833.5		c.2453C>A	p.Ala818Glu	missense	Exon 13 of 14	NP_000824.1
	GRIN2A	NM_001134408.2		c.2453C>A	p.Ala818Glu	missense	Exon 12 of 14	NP_001127880.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GRIN2A	ENST00000330684.4	TSL:1 MANE Select	c.2453C>A	p.Ala818Glu	missense	Exon 12 of 13	ENSP00000332549.3
	GRIN2A	ENST00000396573.6	TSL:1	c.2453C>A	p.Ala818Glu	missense	Exon 13 of 14	ENSP00000379818.2
	GRIN2A	ENST00000562109.5	TSL:1	c.2453C>A	p.Ala818Glu	missense	Exon 12 of 14	ENSP00000454998.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Landau-Kleffner syndrome Pathogenic:4

Dec 20, 2017

Ambulatório de Genética Médica, Hospital Escola da Universidade Federal de Pelotas

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Patient with this de novo variant (parents tested) shows the compatible clinical phenotype, including epilepsy and developmental delay.

May 28, 2019

Mendelics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Jan 15, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with glutamic acid, which is acidic and polar, at codon 818 of the GRIN2A protein (p.Ala818Glu). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with GRIN2A-related disorders (PMID: 30544257). In at least one individual the variant was observed to be de novo. ClinVar contains an entry for this variant (Variation ID: 495226). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt GRIN2A protein function with a positive predictive value of 95%. For these reasons, this variant has been classified as Pathogenic.

Jan 01, 2019

Institute of Human Genetics, University of Leipzig Medical Center

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.28	D
BayesDel_noAF	Pathogenic	0.17
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.89	D
Eigen	Pathogenic	0.77
Eigen_PC	Pathogenic	0.72
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	1.0	D
M_CAP	Pathogenic	0.73	D
MetaRNN	Pathogenic	0.85	D
MetaSVM	Benign	-0.43	T
MutationAssessor	Uncertain	2.8	M
PhyloP100		9.9
PrimateAI	Pathogenic	0.85	D
PROVEAN	Pathogenic	-4.5	D
REVEL	Uncertain	0.62
Sift	Uncertain	0.0020	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.96
MutPred		0.62		Loss of catalytic residue at A818 (P = 0.0643)
MVP		0.88
MPC		0.97
ClinPred		1.0	D
GERP RS		4.5
Varity_R		0.92
gMVP		0.99
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs751455326; hg19: chr16-9862850;